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Android tablet disconnects from wifi every ten minutes
I have a Galaxy Tab A Wifi only version (SM-T580), running Android 8.1.0. It is unrooted.
Every ten or fifteen minutes or so, the wifi drops out. After about 30 seconds or so, it reconnects. No other device on my network has this issue.
Less frequently, the Bluetooth connection drops out, which I suspect might be an associated issue. I usually have the tablet connected to Bluetooth speakers, and every now and the sound will cut out for about twenty seconds, then return.
I have searched online for solutions, and the general advice is to switch from DHCP to static, which I have done. Beyond that I can't get any more specific information.
Is there any kind of test I can run to determine why this is happening?

Logs should help find information about whats going on. Through a command prompt throw the command: (linux) adb logcat -v long > ~/Desktop/logcat.txt (windows) adb logcat -v long > %userprofile%\desktop\logcat.txt thats a standard verbose logcat. Radio logs might also show some insight witht he command: adb logcat -b radio -v time -d > logcat_radio.log along with adb shell dumpsys wifi those commands should put a file on your desktop if not just copy the terminal and paste it to any pasting site such as pastebin, hastebin, or whatever then edit and attach them to your post for feedback.

@BoLawson, thanks for these commands, but I'm unsure where to run them. I no longer have a Linux computer, only Windows. Is there a way I can connect my Android to my Windows computer to run these commands?

Ye yo can, i included the windoes commands too. You just have to install adb through the Android SDK-Platform-tools onto your pc. Then you can open a cmd prompt to throw the above mentioned commands. https://developer.android.com/studio/releases/platform-tools

Windows commands: (windows) adb logcat -v long > %userprofile%\desktop\logcat.txt  thats a verbose logcat. adb logcat -b radio -v time -d > logcat_radio.log radio logcat. adb shell dumpsys wifi thats a dump of wifi stuff.

@BoLawson, Thank you for your help. I've downloaded the Android SDK and connected my tablet by USB, but when I run any of the commands, I get error: no devices/emulators found. Is there something else I need to do to create the conditions to run a test that will reveal some answers?

You need to enable USB Debugging if you have not done so yet. You so by going into Settings --> About Phone --> scroll to the bottom --> tap Build number seven (7) times. A short pop-up in the lower area of your display saying that you're now a developer. 2. Go back and now access the Developer options menu, check USB Debuggingand click OK. The when you connect to your computer and an RSA pop-you should appear. Now just press OK ad you should be good to Go.

@BoLawson, thank you for your instructions, and sorry that I'm going slowly on this, but I just can't seem to get any kind of connection. I've enabled USB debugging as you described. Then at the command line I start one of the adb commands, and it says waiting for device. I've tried connecting and reconnecting my tablet a few times, and turning USB debugging on and off, but nothing seems to happen anywhere. Is there some driver or something I need to install or some other missing step?

Just a stab in the dark, but according to one site, you can try turning off the "disconnect on sleep" option.

Check your Keep WiFi on during sleep options. These allow you to specify when to disconnect from WiFi.
Go to Home > Apps > Settings > WiFi > more >Keep WiFi on during sleep. Hopefully you can stop it from disconnecting at all by choosing an option .

https://www.ifixit.com/Answers/View/280849/Tablet+loses+wifi+connection
There are other models that lose connectivity based on how you hold it or due to an old update, but these are significantly different models that shouldn't anything to do with your model.

Thanks for the suggestion. Unfortunately, on my tablet's interface there is no option for controlling "sleep" mode.

Hope this helps!
Settings>Connections>Data Usage>Restrict Networks
Select your wifi connection
Select not metered
Done


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Google Podcast App and Expired Episodes
With the "Google Podcasts" app, I have been downloading episodes of several podcasts that I listen to, but am months behind and the podcasts only leave a month's worth up.
I thought that downloading them to my phone would keep them around even after they expired from the Podcast's stream, but apparently it doesn't, because the old, unlistened to, downloaded ones are not there.
What the heck?  How do I keep old episodes until I am ready to listen to them?

This is not a new problem, and is mainly a part of the underlying XML that controls the feed. The "current" XML feed is the one the owner defines how many episodes to backlog, and is what most podcatchers rely on to synchronize. If it is defined to maintain X weeks history, that's all they keep until the next synchdate. I have used up to a dozen podcatchers and found all will do the same. I have accelerated my podcast listening periodically to catch up with the oldest files, just because I know a flush is coming. I also use some variable speed; spoken audio does not require high integrity.

I just switched to android from iPhone this year, and the Apple Podcast app would hold them indefinitely, as long as I downloaded the episodes to the phone.

Good for Apple. Maybe their app only synchronizes forward, without enforcing the defined backlog. I have not encountered an app that does it this way.

I'm surprised that Apple is doing it better than Google.  It is good to know, though disappointing, that you've tried a bunch of Android podcasts apps and haven't found one that will hold on to expired episodes.

This is definitely something under the control of the podcast app.  I have found "Castbox" which keeps all of the old episodes, as well as allowing you to download and listen to expired episodes.
I'll be switching from Google Podcast app to this one.  I'm sure there are others that do the same thing, but I got tired of looking for something that should be basic and built into the Google Podcast app.

The current reviews to this app show a severe dropoff from its former height. Random pauses or shutoffs, ad intrusion, podcasts that fail to play, etc. Uncontrollable to the user ; they all outweigh a known controllable issue.

Assuming the "known controllable issue" that you mention is that the stock Google Podcast app deletes expired episodes even if you have downloaded them to save them, please tell me, how do you control this issue?

This may be a feature to ensure continued payment, many Pay-Per-View services will block viewing after a certain period, DMR or Digital Media Rights licensing is applied to the files, these are only licensed for a certain period of time and usually as soon as the license has expired, you'll need to download a new licensed file.
Sometimes DMR is not the case, sometimes this is a programming limit set by the developers.
Usually the correct way to update the XML List View, would be to increment an array by each addition and display the total items in the array.
However, some developers take in to consideration -  the time it takes to select each item for removal..
If you saved 500 items, the list would take hours to navigate and also take forever to clean up/remove items,  it is easier to limit the list length than to have search functions alongside multi-select items.
Some ROOT Access applications will let you stream your system audio into an mp3 file, this would let you Back them Up.

While this answer attempt provides some good background information about why podcast owners may want to limit the number of back episodes available, it does not answer the question "How do I keep old episodes until I am ready to listen to them?"

I am outlining the fact that it is not possible.

source: Stack Exchange

license: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/

sort: votes


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Chrome Remote Desktop with external mouse?
I've been googling for hours and all I can find are a few years old pages saying the only way to do a right click is double touch on the screen...
Has anyone found any better solution since? Maybe with External Keyboard Helper or some similar app??
Also, there seems to be no way to scroll. I've tried the browser version on Android tablet, and it works faster and you can scroll, but there is absolutely no way to press a right click.
It seems imposible that google would not adress this issue for years, since it's really frustrating.

I found an acceptable solution on my Huawei tablet... if I switch to "desktop mode", right mouse click starts working like on PC, so I then connect throug browser client. I don't know if that is possible on other tablets.
Hope this helps anyone.

all_licenses: Creative Commons - Attribution Share-Alike - https://creativecommons.org/licenses/by-sa/4.0/


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android x86 - play AgeOfZ - app exits on launch
I'm running android x86, in kvm (virtual machine manager) VM, installed from the iso. It loads great, and i have the playstore.
When i install a game "Age of Z" it exits everytime when i launch it ?
How can i debug this further, or is there things that i could try to resolve this.
I am not sure if it requires the screen to be portrait, as that is how the game normally runs on a mobile phone.

Goto "Settings" > "Android-x86 Options" and enable "Enable native Bridge"

I have the issue, that I can't click anything inside "Age Of Z" on Android_x86. As well after disabling Mouse Integration in VMware.

Hello. How does this help in debugging?


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Android won't turn on at all
Basically the phone won't turn on at all, not normal boot, not recovery mode, not even the battery percentage show up while charging (just the battery icon with lightning, that's it). it stucks on one screen (battery icon/logo) and stucks there until it ran out of battery again.
But strangely, download mode is accessible, and when i tried to boot from that, the screen is stuck at the logo
my phone is Samsung Galaxy Tab S2 8.0 Inch
Help

Are you rooted or have an unlocked bootloader?

It seems that you have bricked your phone. Download and unzip Odin on your computer. Then download the Stock firmware:
https://forum.xda-developers.com/tab-s2/help/tab-s2-stock-rom-t3199363
Then flash it using Odin. You can easily find a guide to flashing using Odin online.


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Launcher preference not persistent between reboots
I recently purchased the BLU Vivo One Plus 2019, which runs Android Oreo (8.1). After installing kiss launcher and setting as my default launcher, I rebooted my device and the launcher reset back to the pre-installed Launcher3. Note that my other default applications remain, for example I also changed the default messaging app to Signal.
Are there any workarounds for this? How can I retain my preference for the default launcher?

Based on this answer,
adb shell cmd package set-home-activity "fr.neamar.kiss/.MainActivity"

However, this only works from an external device.


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How to get rid of "Device is not Certified"?
I wanted to ask that is there any solution for getting rid of this "Device is not Certified" without/with root? I have flashed Phusson's GSI and then GApps Micro but the first error j get is that on Setup screen, it sticks on Checking for Update no matter how much time I give it to check(Problem 1). The second problem is that I have sent the Android device ID (or whatever) used to certify the device but if no avail. It's still saying not Certified. I can spoof it by Magisk, that it is Certified by a module ummm... I forgot it's name(but it's not PlayStore Visa for sure) but still I can't use Google Play services in my device. Whenever I use an app that requires so, it gives an error that "Google Play Services is having trouble .....". What can I do to resolve this issue and use Google Play Services? (I have Redmi S2 but the issue seems to be on all devices)

Read an article somewhere that stated when you register with google it will still say not certified. However, Google white list your device so you can download and use Google apps. Your device will still say it is uncertified in the Google Play Store settings. This is normal. All this fix does is white-list your uncertified device so you can still use Google apps and services. https://www.xda-developers.com/how-to-fix-device-not-certified-by-google-error/

@Bo Lawson but still, the Google services aren't working properly as I have specified the error in the question.

Google Apps ( GAPPS ) is a proprietary software bundle that requires a licence to distribute... However you can use Open GAPPS ( OGAPPS ) for devices that require the Open Software... https://opengapps.org/

@Gadget Guru I have flashed Open Google Apps on which this is the problem.

Apparently you can get an Xposed module for it, however i personally do not like installing a system level hack called xposed of all things.


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How to run a mouse on android 7.1 (TV Box)?
I got gifted a nice wireless mouse this morning.
I've seen android work with a mouse before so I figured it can handle it as a plug an play, given that this one doesn't have fancy buttons that can be configured - hence needing special software.
Well that wasn't the case, and the manufacturer of the mouse doesn't have android drivers.
Is there such a thing as a general mouse driver I could find. If windows while offline can give basic functions to a new mouse, can we give a helping hand to android to jump the gap?
Normally I'd just go to the store and swap it for a Bluetooth mouse but its a friendly gift and I don't want to do that unless i have to.
The tech is "96 pro plus" tv box (has two usb ports) runs a cable mouse with no problem.
(Just returned it and got a bluetooth replacement in the end)

please provide more information. are you talking about amazon fire tv stick? Is it a bluetooth mouse or a WiFi mouse with/without usb dongle?

h96 pro plus tv box (has a usb port) and wifi mouse. The mouse mouse is named in the fifth word of the original post come on  :)

according to the specification the H96 Pro Plus Smart TV Box has USB-OTG support. just plug in the usb dongle which comes with your mouse

Did you seriously think that I didn't try and came asking for a driver before I even tried the mouse? It has enough usb capability to use a thumb drive, but apparently not enough for a mouse.

you would not believe what questions asked here daily. for android there are no such things like drivers (not at consumer level, at least). Newer android devices usually come with usb-otg support. for mobiles a usb-otg adapter is required. the adapter requests the device to interact in host mode (by short-circuiting pins 4+5). Assuming your Smart TV Box already has this inside, no adapter is required in your case. Try cable mouse instead for testing purposes

A cable mouse is working fine.

please check if the WiFi mouse is working on PC. Maybe there is a switch you missed, or batteries are empty. There is nothing you can do from android side. for mobiles there is sometimes external power supply required, which should not the case for TV box (for mobiles use this charging hub: https://www.amazon.com/dp/B07JZND95Z )

I did, before posting the thread. Its was operational on pc. I guess im trading it in for a Bluetooth one after all. Still the box was worth the money. I would have spent 5 times that for a smart tv that would have been dumber in the end.


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How to install TWRP?
I'm a very beginner and I read some info about ADB tool and other articles about flashing ROM, rooting and things like that. I would like to install TWRP recovery on my phone using ADB tool.
I did the steps in this web page. It showed on the mobile screen that some data or files are successfully transferred (As far as I remember).
Now, when I enter the recovery mood, it's the same screen (same software) that appears before installing TWRP.
Why doesn't the  TWRP interface open? The link said "Done!!! Now you should have TWRP on your device" but I don't know how to open it on my phone.
Phone type: Techno W4

Did you boot immediately into TWRP afyer flashong or did you go to the system first?

first of all, you can not install a twrp.img on "any device" - you must find and download TWRP recovery for Tecno W4 (which is not official supported!) after fastboot flash recovery twrp.img type fastboot boot twrp.img then swipe to modify system (this will rename recovery-from-boot.p and make the twrp install permanent). second, you need to install "dm-verity disabler zip" to make your phone bootable again

https://mega.nz/#!oDIAyYzD!FwF0J3uLjjFfxETu6ylPwko82bUWE79Ex8uWG0-JeDk

@BoLawson Thank you so much for your suggestion. I used the file provided by After I wrote "Fastboot reboot", the phone restarted. I pressed the "Volume Up" button while restarting to boot into recovery mode. It works!

@alecxs Thank you so much for giving me this useful link. It works :) I also did what BoLawson said and I booted immediately into recovery mode after installation.


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Is there anything like live CD for android phones?
We can go into recovery mode in android phones, which is usually home+volume up+power for samsung phones
This answer says that the recovery mode is like a simple OS that the device boots into. This OS then is not restricted by protections and folder permissions implemented by android, so it can see root folders and write to it if needed. I have also once seen (not sure of all the steps I did but I remember doing it) that a zip file in the sdcard root can be used to temporarily change this recovery screen software to something else (I think it was CWM recovery zip file, but it was the type where once you restarted the phone and went to recovery mode again, you would have to run the zip file again to get back to CWN recovery screen. There was a way to permanently replace the recovery screen with a CWM recovery but I didn't try it)
If that is the case, is there anything like a live CD for android? preferably also with a touch screen gui, and able to install and run apps from the phone's internal memory or sdcard? Has this been done or is it technically unfeasible? Would it have to be separately made for different phones?

Unlikely. There's no such thing like a "generic Android version" that fits all devices, see Can I install a ROM made for a different device? – so that "Live CD" must be made for each brand/model specifically. Which is more effort than the results are worth.

i know what cwm you mean - it was a flashable zip signed with leaked samsung oem key which booted into temporary cwm session from "apply sdcard update.zip" in stock recovery. But this worked only for older Samsung devices like Samsung Galaxy Y Duos GT-S6102 with Android 2.3.6 and the zip files were always device specific, because each device requires his own kernel. a common standard for installing apps is a flashable zip. but the user need a custom recovery for this


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Can someone say how can I get to this network management window in my android device
My device is vivo 1718 android 8.1. I have found this Network Management window when I didn't turn on mobile data access for one app. That app pops up an alert to change the network access and when I press to change it, I am directed to this window:

network management window (click to enlarge)
But after that I can't find it anywhere in my settings.

I don't have your device, but do you have an "iManager" app? The Data Monitor in that might have it.

Xiaomi devices has a security app, in which you can set which applications should use data or wifi, under data usage. Vivo is also a custom android device, which also may have such app in its applications.

As in @dewey's comment that is located inside iManager App 'Network management' section. Here is the path.
iManager -> Data Monitor -> Network Management


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Install Python to run speedtest-cli on Android phone with no access to device - via adb
I want to install Python on an Android phone (the phone is connected to a Raspberry Pi so I don't have any GUI or physical access to the device). I can connect to the phone via adb shell and run/install packages via APK files easily. I want to install Python on the device to run speedtest-cli remotely via adb shell. https://github.com/sivel/speedtest-cli
speedtest-cli requires Python. So far I have tried the following based on online articles.

Installed Termux app via APK. I can access the underlying files remotely. I tried to install python using pkg command but could not. Error below.
1|:/data/data/com.termux/files/usr/bin # ./pkg install python
This must NOT be run as root as it will break your environment (root will be required for nearly everything due to changed file permissions)
1|marlin:/data/data/com.termux/files/usr/bin # whoami
root

Installed Qpython on the device using adb. However, the issue is that when I launch adb command to launch Qpython, I see a prompt on the device - "Allow Qpython to access media Options - Accept or Deny". Since I don't have access to the device, I can't select either of the options. Is there a way to send a command via ADB to select - Accept?

I would appreciate any other ideas as well. My end goal is to run the speedtest-cli utility via adb shell on a device that is not physically accessible.

Solved this eventually. Here is what I did -

Installed Termux via downloading the APK and performing adb install com.termux.apk

Remotely launched the Termux app via ADB (monkey) (this is needed to complete the installation on the device) monkey -p com.termux -c android.intent.category.LAUNCHER

Once Termux is installed, I installed python and speedtest-cli on the device using adb input text and keyevents -
adb input text "pkg install python"
adb input keyevent "66"
adb input text "pip install speedtest-cli"

Then navigate to /data/data/com.termux/files/usr/bin. Here you should have the speedtest-cli script that you can invoke from adb shell
/data/data/com.termux/files/usr/bin # ./speedtest-cli
Retrieving speedtest.net configuration...
Testing from XXXXX
Testing download speed................................................................................
Download: 20.18 Mbit/s
Testing upload speed......................................................................................................
Upload: 3.98 Mbit/s

I had to add a COUNT param to the monkey command, i.e. monkey -p com.termux -c android.intent.category.LAUNCHER 1

And you can alternatively do am start -n com.termux/.HomeActivity to open Termux (though you may have to close the soft keyboard, e.g. input keyevent 4)

I basically followed the solution given by rfguy.
But I had this error:

could not find a version that satisfies the requirement speedtest-cli
(from versions: none)
pip is configured with locations that require tls/ssl

I solved installing openssl too on Termux, as follows:
# uninstall Termux
adb uninstall com.termux
sleep 2

# install the apk
adb install -r ~/Desktop/Termux.apk
sleep 2

# open the app
adb shell monkey --pct-syskeys 0 -p com.termux 1
sleep 8

# install python
adb shell input text 'pkg%sinstall%spython'
sleep 2

# enter
adb shell input keyevent 66
sleep 15

# yes
adb shell input text 'Y'
sleep 2

# enter
adb shell input keyevent 66
sleep 60

# install openssl
adb shell input text 'pkg%sinstall%sopenssl'
sleep 2

# enter
adb shell input keyevent 66
sleep 10

# yes
adb shell input text 'Y'
sleep 2

# enter
adb shell input keyevent 66
sleep 15

# install speedtest-cli
adb shell input text 'pip%sinstall%sspeedtest-cli'
sleep 2

# enter
adb shell input keyevent 66
sleep 30

# run speedtest-cli
adb shell /data/data/com.termux/files/usr/bin/speedtest-cli

# hide termux
adb shell pm hide com.termux

You can run this script with a sh .\this_script.sh if you are already connected to the device with an adb connect your_device_ip


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Does Android 8 has journaling enabled in its ext4 files sytem?
Android 8 uses stackable file sytem called sdcardfs, which emulates FAT32 on ext4 on the data partition. Does sdcardfs recognize the ext4 file system and journaling?
In other words, files written using sdcardfs has journal history information created?
On Android 8 it's not clear how the journaling works e.g. can it be used to recover data? Is the new data written to empty fresh areas or first the deleted areas are used?

Does Android 8 has journaling enabled in its ext4 files system?

It depends on a few factors. OEMs can possibly disable journaling e.g. on system partition as it's always supposed to be used R/O. These days ext4 and f2fs are commonly used filesystems on Android, so first make sure you have ext4 on userdata partition. f2fs is by-origin a log-structured filesystem which is a circular buffer, that's what a journal is but the functionality differs.
Filesystems are part of Linux kernel, not Android (AOSP) itself. ext4 by default is created with journal, though it depends on mke2fs.conf, and can be disabled with mke2fs or tune2fs option -O ^has_journal.  Journaling support can be checked from filesystem features by executing tune2fs -l /dev/block/bootdevice/by-name/userdata | grep has_journal (or use dm-0 block device if userdata has FDE) but it requires root. As alternate if mount | grep 'on /data' shows data={journal|ordered|writeback} option then journal is enabled for sure.

Does sdcardfs recognize the ext4 file system and journaling?

sdcardfs itself doesn't have a journal, but since emulated filesystem is stacked over /data/media (which is ext4), the files created through sdcardfs are recorded in underlying filesystem's journal.

On Android 8 it's not clear how the journaling works e.g. can it be used to recover data?

Yes definitely, if you have root already and the data isn't overwritten. We have tools like extundelete which are very effective. But do consider factors like TRIM and others described below and in given links.

Is the new data written to empty fresh areas or first the deleted areas are used?

Well that's a different question, again it has nothing to do with Android. The question is how often a filesystem overwrites deleted data blocks and it's not simple to answer. Create a new ext4 filesystem, create a file foo inside it and delete it. Create new file bar and it will take the inode block and data blocks freed by foo. Delete bar and create file baz, it will occupy the same space. However in actual things are complicated. Will the data blocks of deleted file be immediately overwritten or not depends on whats the size of new file is, how much fragmented your filesystem is, how much free LBAs you have before the logical location of deleted file etc.
PS:
Things are different on f2fs, it's the Flash Friendly FileSystem, so as a wear-leveling strategy it preferably writes data to new empty blocks (free segments), so that FTL doesn't have to Erase cells, trying to reduce the E/P counts on flash memory. Later it does background garbage collection (GC) synchronized with FTL to release LBAs corresponding to deleted data. But the tools like debugfs aren't readily available for f2fs to explore deleted inodes and to lookup corresponding data blocks from journal. So from data recovery's view, f2fs isn't very friendly (AFAIK and experienced).
RELATED: What Makes Recovery of Deleted Data Difficult / Impossible?

Where would I find the journal file itself? I'm actually looking for the journal file of the 2nd partition (ext4 partition) of a micro SD card that is inserted in the device.

@Sruly journal is stored in an invisible file usually located at inode 8. See https://ext4.wiki.kernel.org/index.php/Ext4_Disk_Layout#Journal_.28jbd2.29 or any other EXT4 resource. It's not specifically about Android.


text:
In Android 8, during video recording, how the data is saved to disk?
In Android 8, during long video recording,
1) how often does the recorded video data is written to internal storage?
2) What is the size of each piece of data written?
3) Is the data stored contiguously in the internal storage or each piece of data is stored independent of each other?

Question 1 and 2 depend on the app you are using to record video. An app developer can better tell about this. Question 3 depends on the filesystem you are writing to.

What would be the answer for a typical app such as the default app in a Samsung phone. The filesystem is sdcardfs stacked on  ext4.

I have no idea at all, but I'd use inotify to see live changes made by an app to filesystem.


text:
Deleted my stock phone application from android phone after rooting as a result can't call for now
I recently rooted my HTC desire 728 and by mistake deleted the stock phone app and as a result, now I can't make calls ... the phone is not showing any sim signals too and when I go to sim settings it shows  process.com.android.phone stopped  ... what can I do now? I had factory reset the phone already a couple of times but the after root deleted apps are not showing up ... please help me out

It seems you have taken no backup, which implies that you have to flash the stock firmware. Since you have rooted your phone, I believe you already have a custom recovery like TWRP installed (if not, go ahead and flash one. Search google for the exact instructions for your phone). Then search Google for the stock firmware, and you should be able to find a version of the stock ROM. Download and move this to the phone storage, and flash it with the custom recovery. You might have to clear all internal storage data and/or Dalvik cache and system partitions before/after the flash. Check Google and XDA Developers for the exact instructions.
Note that this will delete all the data of your internal storage, so make sure to take a backup before proceeding. You will lose root access as well, and the custom recovery might be overwritten with the stock recovery.


text:
Why isn't the OnePlus 7 Pro compatible with Google Daydream?
Is there any shortcoming in the hardware offering of the One Plus 7 Pro that makes it ineligible to run Daydream? I can't see anything that specifies what exactly makes a Daydream phone special.
I see the YouTube VR page in the Play Store says that my hardware isn't compatible. But it doesn't tell me why it isn't compatible,


text:
Detail information on running scripts on the recovery screen
I am looking for more detail information regarding the process mentioned here:
1 https://forum.xda-developers.com/showthread.php?t=2058944
2 https://forum.xda-developers.com/showthread.php?t=2307355
(1) says that selecting "apply zip from sdcard" in the recovery screen will run the script and perform the mentioned commands. I suppose at this point there is no concept of  android OS's root user? Is this correct? Am I allowed full access to all the files and folders in the sdcard and phone memory at this point?
The script in (1) also mentions BusyBox. I know there is an app called busybox which provides some tools, but since the android OS has not loaded up to this point, I guess the busybox in the script represents something else? Wikipedia says busybox is an old set of linux tools, so does this mean it is present by default in all android phone firmware?
The zip file containing the script in (2) contains a file called "busybox" in the zip file root (no extension, binary file) and the one in (1) doesn't. What does this mean? (1) and (2) seem to be for different phone models, but shouldn't all phones have the run_program() and delete() commands mentioned in those scripts? Would these scripts work on a different phone model? How much chance is there of the phone getting bricked? (I have stock firmware + Odin for my test phone and I am ready to format and reinstall if needed, I just want to know if there is a possibility of bricking it so badly that even Odin wouldn't recognize it)
Regardless of whether I am able to mount the sdcard/phone memory and run programs on the sdcard or not, I suppose the commands in the script such as ui_print() should work on any phone. Where can I find more commands that can be used in such a script file, and more details on how such scripts actually work? The answer can be limited to samsung phones if there are no general answers.

Yes, from custom recovery there is generally a high risk of deleting everything in theory. Your data security is completely dependent on the developer's coding ability and your trust in him. Luckily a full backup should be sufficient enough to restore everything in case of damage.
A flashable zip is usually pretty generic. in your example it's only purpose is modifying device specific things, so the reason is not the script language itself but simply the content of which apps will be removed. The first link is for indian apps, the second link is for samsung apps. Samsung is a good example because it has a separate partition for its bloatware - you need a flashable zip which delete apps from /preload instead from /system.
linux executables doesn't have file extensions like *.exe - busybox/toybox/toolbox are just such executables. busybox is a multicall binary wich emulates most of linux commands like (ls cat dd grep find ...) in a single file. it's main purpose was to safe disk space. if you see any busybox app in Playstore it is always just a install helper for this binary.
android default is toybox (same as busybox but under apache license)
http://landley.net/toybox/faq.html
Edify is a very limited script language only used in flashable zips
https://source.android.com/devices/tech/ota/nonab/inside_packages


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Android (Galaxy S8) not showing Bluetooth "Available Devices" screen
My Galaxy S8 is no longer showing "Available Devices" screen when I enable Bluetooth. I used to be able to see a list of available devices when I enabled Bluetooth.
Can this be fixed? Thanks in advance.
https://www.techjunkie.com/samsung-galaxy-s8-and-galaxy-s8-bluetooth-pairing-mode/

The problem is still there of not getting the auto-pop up, but I am closing this since you can still work around it by going to Settings > Connections, and clicking on Bluetooth (next to its On/Off toggle) to see the list of available devices.


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Background usage even if the app put to sleep
I have put the WhatsApp to sleep (App Usage --> Put app to sleep ( ON ) ) but when I checked on the battery usage, it shows 1 h 6 min.
I'm using Android Pie on Samsung Galaxy Note 8.
How I can ensure that the app will not use battery in background. I guess one way to use the 'Force stop' in app manager.

How did you put to "sleep"?

@IrfanLatif App Usage --> Put app to sleep ( ON )

It seems to be a Samsung specific feature, not of AOSP. So I'm not sure what it actually does to the app, but for sure it must not be completely killing the app. Stock Android uses different phenomenon to put restrictions on apps' background activities e.g. doze and app standby. Battery saver mode aggressively forces apps to standby as well as blocks network activities.

But the best background limitations are applied with appops RIN_IN_BACKGROUND denied, in which restricted apps cannot run jobs, trigger alarms, or use the network, except when the app is in the foreground. However none of them kills the app. So you may see somewhat resources used by app.


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The issue with the Fingerprint unlocking
I've got this Android device I bought recently. It is Huawei Y9 Prime. But I discovered yesterday there is an issue with the fingerprint ID. The lock can be unlocked by anyone!!! the device unlocks for all the fingerprints of all the people. So what should I do now? Is this a common error?

Can you edit your post with the version of software (in settings)

Assuming you bought the Huawei Y9 Prime, the phone is so new that its possible you have found a software bug/flaw or have a malfunctioning unit. Or it could be user error.
Based on your post history, the purchase is a few days old. I have a few options:

Contact Huawei and notify them that there is a problem. They will probably recommend...
Returning it to the seller for exchange with another unit. If you bought it in a physical store, you can show the clerk who can then verify that the fingerprint sensor is behaving incorrectly.
If the second unit is bad, you can either return it for refund, or live with PIN lock with the hope that it is a software problem that can be patched.

Personally before returning/exchanging the unit, I would record a video setting up a freshly reset device, show the software version in the video, setup a fingerprint unlock and have a different user unlock it. It may just a manufacturing defect in the early production run or the software itself isn't the final consumer version. Either way, video proof can improve the odds of a fix if the problem is real.


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Android 8.0 | How to show the day of the week on my widget (HTC CLOCK) or Notifications area at the top
so I have this problem of not knowing the day of the week (Monday, Tuesday,...) and having it on my HTC 10's home screen or the notifications pane would help a lot. I remember that one of the above-mentioned items showed the day of the week along with the date, but I don't know why it is gone. Any help will be much appreciated.
P. S. Priority is to avoid installing third-party apps for this simple thing.


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How to permanently disable or remove preinstalled apps?
I have an older Google Nexus 4 (by LG), running 5.1.1 Lollipop (latest supported version). I want this to be my daughters first smartphone, and want to lock it down as much as possible.
So besides my own user account on the device I created a second user account for her. I installed the apps she should be able to use, but want to restrict others.
So I went on and disabled all apps she should not be able to use.
However, all disabled apps keep re-appearing on her account after a day or so.
I went on and disabled automatic app updates on my own user and on her account, then went on and again disabled all apps on her account, but they keep re-appearing.
Question is: How can I permanently remove apps (especially the pre-installed apps like YouTube, Google, News, GMail, Hangouts, Play Books Play Music etc.) from her user account?
Rooting the device is not an option.

See if my answer helps. Check the non-root section. https://android.stackexchange.com/a/208271/96277

Try this way:

Connect device via ADB
Go to ADB shell
adb shell

Find your target app by listing all the apps
pm list packages

Remove app like this
pm uninstall -k --user 0 com.android.inputdevices


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What is the small hole on the top of the pixel 3a?
Many reviews note the pixel 3a has a headphone jack on top. Yes, I like it, too.  But I can't find anywhere that describes the other little hole, the one on the right in this picture.  What is it?

If you look at the specs for the Pixel 3a and open up the Media & Audio section you'll see:

Stereo speakers
2 microphones
Noise suppression

The small holes are for microphones, usually multiple ones are used to improve call quality, i.e. suppressing background noise.


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Cross-platform compatible encryption of SD-card for Android
How would I go about encrypting my brand new 256GB SD-card, which is meant for my Android phone, considering the following:

Card should be usable across multiple Android devices, and other platforms (Linux..). As a consequence, native Android SD-card encryption is not a solution as the contents are not readable on other platforms, nor recoverable if the phone fails or needs a reset.
Use case is protecting data, mostly pictures, from phone thief/finder, not from a gvt agency or police. My understanding is that most encryption methods are broken on Android for these purposes as the keys are often accessible from memory. In that sense, the phone is considered trusted once unlocked, so encryption should be transparent so that files are accessible via standard phone apps (i.e. pictures show in Gallery).

Ideas:

Full disk encryption methods such as Luks. I found this program : EDS which apparently can mount Luks volume if the phone is rooted. I have no idea how efficient this is performance-wise, or if it is safe for the card.
Commercial programs using their own file-based encryption but available on multiple platforms such as Boxcryptor, or Cryptomator. Their purpose is originally to encrypt files before storing them in the cloud. It doesn't seem that I can access files using regular apps using this solution.
Changing my phone to one on which I can install UbPorts :)
Using Termux and rooting the phone to mount a gocryptfs or other encrypted file system
Using Android default sd card encryption (FDE/FBE), dumping memory to get access to the encryption key and using that from Linux to access files
Other welcome idea !

I cannot find any info about this use case which seems very strange to me..
Thank you very much for any input !

Thanks for all your answers.. for now I went with the default Android encryption because it is a lot simpler to implement.. I found a couple of write-ups on how to break Android FDE on older Android versions, but nothing on how to recover the fscrypt key (ie from memory) which is used in newer versions. Any idea if this is feasible or not? // Have a great day everyone

Recent devices only use FBE. The path /data/misc/vold belongs to Irfan's description of FDE.

FDE
In previous versions Android's default encryption for /data and Adoptable Storage was Full Disk Encryption (FDE) which is a custom implementation of dm-crypt. userdata partition (on FDE as well as FBE) is hard (or impossible) to decrypt off-the-device because of hardware-backed encryption. In case of Adoptable Storage implemented since Android M, key is saved at /data/misc/vold/expand_*.key, you don't need to dump memory but accessing /data requires root. Key is stored unencrypted because of the assumption:

Because the contents of an adopted storage device are strongly tied to the Android device that adopted it, the encryption keys should not be extractable from the parent device, and therefore the storage device can't be mounted elsewhere.

But if you are already rooted and once you have the key, it's possible to decrypt the SD Card on a Linux machine using dmsetup. Also note that removing physical SD Card will break your /sdcard and the apps you would have moved.
FBE
Recent versions of Android mostly use File Based Encryption (FBE) which bases on Linux filesystem encryption (for ext4 and f2fs). It doesn't use a single key, instead the master key generates per file (per inode in fact) keys on the go. On Android encrypted master key is saved to /data/misc/vold/user_keys/de/ and /data/misc/vold/user_keys/ce/ along with other related files. Further subdirectories are named after the UserID e.g. 0 for device owner. Here de is for Device Encrypted storage which is entirely hardware-based encrypted and is available at boot without user interaction. ce is Credential Encrypted storage which requires user PIN/password for decryption in addition to hardware-backed key. Different directories on /data partition are (not encrypted or) encrypted with different keys; DE or CE, for user 0 or user 10 and so on.
So each user has 2 encrypted keys - one for CE and the other for DE - just like the encrypted key stored to the footer of userdata partition as in the case of FDE. The keys can't be simply used for decrypting files on PC as opposed to a single key required to decrypt whole block device in case of FDE Adoptable Storage. Also FBE with Adoptable Storage doesn't work on Nougat and Oreo, and doesn't look very stable on Pie. I'm not sure how it's gonna work when things get streamlined. If some implementations store unencrypted (CE/DE) master keys in /data/misc/vold/user_keys/, there would be higher chances for FBE to work across multiple platforms.
OTHER OPTIONS
If you don't want to go with Android's native FDE or FBE, you can manually setup dm-crypt (plain / LUKS), or try FUSE-based solutions first like encfs or gocryptfs; they are relatively simpler. Binaries are available here.
FBE can be manually managed with fscrypt tool but I don't think that would be a very feasible option at the moment. You may give a try though.
ecryptfs is another Linux kernel's native feature. Android by default never used ecryptfs AFAIK, so it depends on ROM builder if they built kernel with CONFIG_ECRYPT_FS=y or not. You might need to rebuild kernel.
All of the above options work well but all need root access and manual configuration on Android e.g. an init.d script, or a third party solution.
Or if you just want to encrypt selected directories and not the whole SD card, give MiXplorer a try. It includes Java port of encfs which doesn't require root. However directory decrypted in MiXplorer won't be accessible to other apps. For Boxcrypter type of use case, I prefer rclone because it's open-source.
RELATED:

Decrypting microSD card on another Android device or desktop computer

much clearer indeed, thank you. However, I still don't understand where I can find the FBE key so that I can decrypt the files from Linux.. any idea ?

Understood, thanks.. as a result I guess there is no practical way of implementing this... I will stick with Android stock SD Card Encryption and use a sync software to backup and synchronise my files. If I change my phone hopefully I can decrypt everything first so I don't have to copy everything back again from backup to the card... cheers everyone and thanks

When you are using FDE and your unmount and put out SD card (adopted storage) nothing bad happens. When you insert it again will work normally.

@QkiZ correct, provided that you don't 1) Forget the card 2) insert another card 3) reset the device.


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Adoptable Storage corrupted my SD card
I'm using LG Leon on Android 6.0 Marshmallow. LG doesn't allow making SD cards internal storage. I have made my SD Card broken because I used adoptable storage.
I had to use a guide that required me to use ADB. So what I did? I opened ADB, wrote: sm list:disks or something similar, and then did type something to format the SD card as internal.
Everything worked for a day or more, and I moved an app (for some reason it didn't automatically save to SD card) and my phone restarted. Then it got into a bootloop, and it wouldn't turn on until I would get my SD card out of the phone. Then my SD card stopped being recognisable (yes, I tried to get it out of the phone and insert it back). Then I pressed "Forget SD card" or something similar. Now my card isn't recognisable on my phone or on my laptop.
Please help me.

you did nothing wrong. just repeat all steps with another sd card. run diskmgmt.msc or gparted from terminal for re-partitioning the "broken" one

@alecxs Could I get a little step-by-step guide? Also, I don't  have a second SD card.

Usually a smartphone can't corrupt an SD-card by using it. The only possibility to degrade an SD-card would be by a large number of writes over a long time (I am talking about months or even years).
Are you sure that the SD-card is really broken? May be you simply need to re-partition it.
In case the card is really dead I see two possibilities:

The SD-card you have is a fake, claiming to have more memory than actually available on the flash chips inside. If the SD-card was new and the price was cheap compared to the size than this is the reason for a very high probability. I strongly recommend to test every new SD-card on your PC using a program that allows to identify SD-card fakes like H2Testw
The quality of the SD-card was so poor that something went totally wrong (e.g. overheated) so that the SD-card is now defect.


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SSL certificates not updated on old Android
I have an old Android smartphones. More and more websites stop working because my chrome browser doesn't trust the root CA (Outdated or missing CA certificates). Obviously the root CA list is only updated via an android os update.
Any ideas how I can migate the problem? (Beside adding them manually / buying a new phone) Lineageos isn't supported as well.

You could try a different browser. Would that work?

The Firefox works... But it has its own cert store. Changing the browser won't help with apps that also requires trust on ssl certificates.

How old is that smartphone? Usually you can add your own CA certificates in the settings.

@firendlyQuestion Please edit your question and say exactly what Smartphone you are talking about (brand, model and Android version). Anyway if your phone is that old you should be able to root it and the edit the certificate list.


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Stop notifications from chrome spam
My new Android device is full of spams. I get chrome notifications continuously from a website I did not even visit once. looks like a gossip site. Are there any methods to stop these annoying notifications?

Try the following:

Open Chrome, then Settings,select Site Settings
Click on Notifications. Check if that website is listed among the Allowed sites.
If yes, Click on it. Remove or block the permissions given to it by clicking on the permissions

Thank you. the answer is really very helpful.it worked.

@KevinBarnes Please see the Tour on how to the site works. If the answer helped you, then you can mark it as accepted.


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Repairing a suddenly dead Samsung Galaxy Note Pro 12.2
Samsung Galaxy Note Pro 12.2
(1,
2)
bought used for diversity of Android tests during app development. Died suddenly a year later.
Would still like to keep it running. It now has no sign of life when plugged in, but
because the battery was still holding a 3-hour charge when last used, I suspect that the sudden death is
not caused by the battery. The battery would have dwindled more slowly.

Net chatter suggests that the USB connector is prone to breaking. Have you been there? Is this repairable?
I am content to use it with the power cord attached. Yet replacement battery sellers suggest that presence of a working battery is necessary. Have you been there? Can you confirm one way or the other?

I used the 10.1 tag because the 12.2 is identical in build quality (or lack thereof) to the 10.1. Your experience with the Samsung Galaxy Note pro 10.1 is likely very relevant.

afaik you need a real DC current (not just a pulsed DC from AC-DC Power Supply) best stable solution is always battery

@alecxs Interesting. So the device is sold with a modest adapter, and the battery acts as a super-large capacitor? Does this happen often?

battery is not used as capacitor. but simplyfied, yes it's a common design to use power supply just for charging purposes, while the current is taken from battery only. buy this maybe it is sufficient for your needs https://www.aliexpress.com/item/32858352800.html

maybe interesting too: some batteries can be boosted by heating a little. once you get it above ~2.2 volts the device should start charging again https://android.stackexchange.com/a/145155

@alecxs That's new. I'm assuming heating up to maybe 60C, not much more. What's a safe way to do it? More importantly, Could the battery have died suddenly? Doesn't sudden death mean that something else failed?

safe way is put it in the sun :) i have no clue, but worth a try. maybe the android battery stats was wrong and lied to you, because it was recognizing voltage on data pins 2+3 but the charging voltage on pin 1 was in fact missing or weak current. but that's just rather far-fetched


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how to always ask password in k-9 email app android
I have installed K9-mail in my android phone and mapped my 2 email accounts. When I open the K9-mail app, it opens without asking the email account password.
But I want to make the settings to always ask for the password before it opens an email account in that app and before its sync with the respective servers.
I have Thunderbird on my desktop and have this setting, which always prompts me for a password for the respective email accounts before it syncs (connect to email server). Could anyone help with this, please?


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Can my phone be monitored by my family members without them ever accessing it?
It is actually for a friend, so less info. But she suspects that one of her family members know what she is watching on youtube and maybe also about Whatsapp messages. Do you think that is possible? The family member has is in a foreign country and has never accessed her phone. And she has not installed any apps that the family member has sent. What do you think?

definitely - just login to any PC with same google account - you will have same youtube history, and with WhatsApp Web you can see all messages. i recommend to remove the google account from phone settings and create a new one (required for Play Store) then goto google settings and disable as much as you can https://myactivity.google.com/myactivity?restrict=vaa

Thanks! It was exactly how it was done. I am asking her to change the account.

Only if they have the password to her Google Account or her device is set in the Family Friendly mode (which I find very difficult to happen, otherwise she wouldn't be able to use WhatsApp), tell her to try changing her Google Account password, also, she can install Kaspersky Internet Security (https://play.google.com/store/apps/details?id=com.kms.free) to check if her device contains any Spyware or related software.
I hope this helps her, if you have any doubts or want further information please let me know by commenting.


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Why do some apps still get push notifications when there's no data?
I have both Facebook and Instagram blocked from using data on my phone (only WiFi), but I still get push notifications from them when not on WiFi. How and why is this happening, and how do I stop it?


text:
When using Google Payments for an in-app purchase, does the App admin see any information identifying or associated with your google account?
For example,
Let's say I have 2 play store accounts signed in on android:

alice@gmail.com
bob@gmail.com

Event 1:
I sign into the app using alice@g, and then make a payment in the app using the Google Play Payment Method (GPPM) associated with alice@g's account, and which is then assigned order: GPA.111...
Event 2:
I then delete the app's data in settings and remove then reinstall it on the same device, but sign into it using bob@g. I then make a payment in the app using the GPPM associated with alice@g (since it is available and already on the phone), which is assigned order: GPA.222...
My question is (under the assumption that the app is not given the unique device id) for Event 2, is there anyway for the App-admin to associate bob@g's login with the alice@g login (for example, does the GPPM send the app admin an e-mail address such as alice@g or an id, such as gppm-id-alice, or gppm-randomId-associated-with-alice) or is each payment with GPPM fully anonymous?

It is not fully anonymous. Google Payments Privacy Notice under the "Information that we collect" section states that:

For example, when you make a purchase or transaction using Google Payments, we make certain personal information about you available to the company or individual you purchase from or transact with. This includes sharing your personal information with the developer from whom you purchased when you use Google Payments to make a purchase on Google Play. When you add a third party form of payment to your Google Payments Account, we may exchange certain personal information about you, such as your name, profile image, email, IP and billing address, phone number, device info, location and Google Account activity info, with the third-party payment provider as necessary to provide the service.

Information about the account used for the payment is shared. If that information is an email address like in your example, the app's developer receives Alice's information not Bob's.


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How granular can the app developer set the permissions to avoid turning the user away at the "Permissions to Photos, Media and Other files"?
When a Notes app (like Google Keep, Wunderlist, Stickynotes) etc asks for permissions to "Photos, Media and Other Files" (PMOF) on your device, the user can get a bit uncertain. So essentially, can the app just ask for Files permission and not Photos,media? Are the permissions defined at such granular level post Android 6.0?

PMOF means android.permission.[READ|WRITE]_EXTERNAL_STORAGE, which, once granted, allows app to read whole /sdcard. See this answer for details how this happens at back end. Now the app can read / write / inspect /delete / rename / modify / upload / encrypt whatever you have in shared public storage including photos, videos, documents, contacts, messages, backups and so on.
Unfortunately Android offers no more granular control over this filesystem level access. However Storage Access Framework (SAF) can be used to not let app access whole /sdcard filesystem, but only a specific file or directory (included subdirectories).
Android Q is introducing a more fine-grained control with Scoped Storage.


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Restore folder of icons to home screen
My one year old was playing Balloon Pop on my Pixel 2 and accidentally removed a folder of icons from my Home screen. There happened to be 11 icons in that folder and I'm hoping I can easily get it back without rebuilding it manually? (Some sort of undo function or "trash" area?)
As a side note, any recommendations on how to lock the home screen icons? The icons tend to get accidentally moved a lot, though this is the first time they got completely removed.

What launcher do you use?

@ReddyLutonadio - default Pixel launcher. I think I know the answer to the side note now. :)


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How to stop Do Not Disturb turning on every day at midnight?
Every day at 00:00 my phone goes into Do Not Disturb mode. I have turned off Do Not Disturb in all settings. I have tried with scheduled Do Not Disturb and with the schedule turned off.

No matter what, it turns on every day at 00:00 without my permission.
How do I stop this?

look in Settings - Apps - Configure - Special Access - Do not disturb access, or in Settings - Apps - Configure - App permissions - Phone, or in Settings - Accessibility - Services for third party Apps like Tasker/Macrodroid/Automate

In Settings - Apps - Configure - [Menu] - Do not disturb access "Digital wellbeing" asks me for overrride then won't let me do it even after clicking "OK" (despite "Digital wellbeing" not existing as an app on my phone).

adb shell pm uninstall com.google.android.apps.wellbeing

Is there really no non-adb method?

you can install terminal emulator app and type pm uninstall com.google.android.apps.wellbeing or install any third party app manager where you can freeze packages

Failure calling service package: Failed transaction  I can see it if I show system apps but only force close not uninstall.

I don't even think it's a google app at all it looks more like a Samsung one. Apparently I need root for a terminal emulator which is not possible.

if not working from terminal emulator, try it from adb shell it has different permissions pm disable --user 0 com.google.android.apps.wellbeing will freeze the package. If you know which app causes this just clear data from app manager


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Android: the print quality is bad
we have a problem with Android printing. The print qualitity is bad.

The font has podium on the edge
"Gaps" in the font inside
broken lines

We have the following printers:

Samsung Xpress M2026W
Brother HL-L2350DW

The connection is made via WLAN.
We tried the following variant:

Samsung & Brother Print Service:

via external Apps (Adobe Reader)
our own native App (printerHelper, printManager, ...)

Samsung Mobile Print App:

Direct call and print of a PDF / image (JPEG / PNG)
Call through our app with explicit intent

Samsung Cloud Print
Brother Mobile Print App:

Direct call and print of a PDF / image (JPEG / PNG)

The only variant with good print is printing with a desktop PC (Windows 10, Ubuntu 14.04 and 18.04)
So there is generally no Problem with the printers.
It was tested on Android 6, 7, 8 & 9 and many tablets and smartphones (LG, Lenovo, Nexus, Pixel and Huawei)
To exclude images and fonts that could cause problems, we also tested third-party PDFs and docx with Arial.
Are there solutions to that? Be it settings (Android, manufacturer App or printer) or programmatic solutions? We would be so far, the printer directly address, if this is possible?! Also, we could imagine hiring consulting firms, if anybody knows any on this topic?

I had the same problem when printing from android to my Brother HL-2340D.
My prints included a barcode which couldn't even be scanned when printed from my android-device.
What I did to fix it was downloading Brother Print Service Plugin
With this installed you get a new option in the list of printers. With this one there's a new button in the print-settings, "MORE OPTIONS" pressing this takes you to a new with 2 more settings, 1 being Quality. The options there are "Normal", "Fine", "Best" with the default being "Fine". This prints in about the same quality as without the plugin. Maybe a tad better. "Best" prints in about the same quality as the default settings on my pc, which is 600 DPI.
Oh, and the "Normal" option is anything but normal.


text:
How to dismiss non-removable notifications?
So I've got a new Android phone like a week ago. But still couldn't get used to it. Still, couldn't figure out some part that how is it workes. Now, this is about notifications I get by installed apps. On the drop-down menu, I get it usually but some of these notifications are not removing even if I try to remove it. Most of them are saying that some kind of app running. And it won't dismissive.
Does anyone have any idea how to remove these non-removable notifications?

I don't know about making them removable but MacroDroid app can swipe them away automatically. https://android.stackexchange.com/a/163569/96277

What version of Android are you running? The point of these notifications is that they remain there to warn you that the app is doing something, but if you really don't care about them you could, depending on your version, long-press them and mute them in the settings.


text:
If Bluetooth Then Hotspot
I have a Pixel 2 and I just installed a Android head unit in my car. I am looking for an app or script that when I get into my car and my Pixel connects by bluetooth to my head unit it turns my Hotspot on so my head unit can get internet connection. I tried IFTTT but that doesn't have an option for it. I am new to Android a bit but pretty computer savvy. Has anyone seen an IFTTT like this or know of how this can be done?

I am looking into something similar. So far IFTTT does not appear to have any hotspot applets. Various threads talk about an app called TASKER. Not tried it yet. 1 week for free, then one time purchase of about $5.

@JeffEckstein I saw that too but for it to work on my Pixel with Android 10 I have to root it which is not easy with Android 10 and add TASKER as a system level app and then build the task. TASKER is hard as hell to learn and I have been working on it for 9 months and still haven't figured it out.


text:
Repair IMEI of a rooted Motorola Moto E4
I have rooted my Motorola Moto E4 (XT1765, MetroPCS, Qualcomm processor - Not MTK) on Android 7.1.1 with Magisk. Now I want to repair its IMEI.
I've tried Miracle Thunder and many other tools, but nothing worked. When I try the Miracle Thunder tool to repair IMEI, after a restart, the baseband becomes null or unable to check IMEI.
Can you please suggest a method to repair its IMEI?

To resolve null baseband, flash the same baseband files:
fastboot flash modem NON-HLOS.bin
fastboot erase modemst1
fastboot erase modemst2
fastboot flash fsg fsg.mbn
fastboot reboot


text:
Facebook app appears twice in "Open With"
I was trying to open a link to a Facebook post sent in Facebook Messenger recently, and I got an unexpected "Open With" dialog, asking whether I wanted to open it with...

Facebook
com.facebook.katana
Facebook
com.facebook.katana

The exact same app entry repeated two times, like so:

This looked suspicious to me. Is this possibly a sign of some malware that's masquerading as Facebook on my phone? Or is it just an innocent bug/confusion within the Facebook app or Android system?
Are there particular steps I should take to fix it?
Facebook appears only once in my "App info -> All apps" list.
I'm running Android version 9 on a Google Pixel 2. My Facebook app is version 232.0.0.35.115 - I'm happy to dig up any other diagnostic information that might be useful, just please let me know in a comment what needs to be added/clarified.

That's because Facebook app registers itself for different intent types that it can handle. When opening the link (you tapped), two of intent types are matched by Android's activity resolver, so the app appears twice. A little more detail here: https://android.stackexchange.com/a/218441/218526

@IrfanLatif Thanks for the info! Post that as an Answer and I'll happily accept & upvote it. :)


text:
Sharing gmail can 'potentially' erase my device
Me and my friend use shared email (about 15 people), then i realized from that gmail account i can see the connected phone (specially android), and i can play around with that (lock phone, ring) and wipe out the device / factory reset, and i thought this is so ridiculous, who would have thought sharing email account can do that much harm, to my question :
Can i select which gmail account (strictly personal account) have access to wipe my device and which not?
edit: currently i had find my device setting disabled

Possible duplicate of Can my phone be monitored by my family members without them ever accessing it?

@alecxs nope, it is not

i recommend to remove the google account from phone settings and create a new one

Why don't you uninstall Find my Device, or deny it administrator privileges in settings? In that way, you shouldn't fear someone else erasing your device.


text:
inject recorded audio in an in-going call
I need to inject a recorded voice during a live call to test the network, how can I do that?
I got a rooted device working on Qualcomm  MSM9889 soc.

https://stackoverflow.com/questions/57393147

@alecxs its also my question xD


text:
UDP stream capture and replay
I am capturing audio from a radio device to my android using tcpdump.
How can I take this cap file and replay the UDP stream within it? As I want to replay the audio I got from the radio.

UDP usually uses dynamical port numbers on client side, therefore just replaying will not work.
Note: The following bases on the assumption that the audio stream is transmitted using a common standardized protocol and is not encrypted or otherwise protected like it is on streaming apps like Spotify, Dezzer, ...
Instead you need to extract the UDP data stream from the created packet dump (usually in pcap file format). See for example this question.
Then you need a streaming server software that allows to stream the data you have extracted. The server can run on a PC that can be accessed via network from your Android phone or on the Android device itself. I assume that the client software on your Android device allows to specify the audio streaming server.

I managed extracting the packets to pcap file using tcpdump. Now I have the file on my Android device, can you recommend an app that will be able to replay it and recreate the audio?

@Dean You also need to find out what data format is used, analyze the extracted data if it can be directly played within e.g. VLC on a PC. Regarding the server I can't  make any recommendations, sorry.


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ST21i Removed boot flag
I was trying to boot from the sdcard, as I thought it was a boot order issue, I disabled the boot flag on the boot partition. Now my phone will not turn on, or enter bootloader. I have found various guides to booting from an sdcard, however they require flipping a switch on the board, which does not appear to be there. Any ideas on how to fix this situation. I would like to be able to get the phone to a working state again, without having to wipe it.
Edit: Having looked a bit more, the phone is detected by the kernel, as it displays in dmesg and is also listed by lsusb. This is on ArchLinux 5.2.13 I have tried qmicli but that appears to only work if the driver is cdc-mdm whereas it is using qcserial. when connected, it generates /dev/ttyUSB0 and /dev/bus/usb/002/* which is a character unbuffered device file.

please provide some introducing stuff

@alecxs What information would you like to know?

https://www.gsmarena.com/sony_xperia_tipo-4718.php is this the device you are trying to boot from? Where did you get the idea of booting from sdcard, and what is the reason/goal (what tutorial did you follow, link)? Which rom you trying to boot (download link)?

Nevermind, so you just asking about How to flash stock ROM without losing data? https://forum.xda-developers.com/xperia-j-e/general/xperia-tipo-st21i-official-thread-root-t2172652

I was not following a tutorial, I simply first thought I would try to lauch ArchLinuxArm on my phone, so I copied it from another sdcard to my phone's sdcard(ext_card). Tried to boot, but it booted as normal into android. I then set the boot flag on the arch partition. Still booted into android. Thought it would be due to boot order that it was not booting into arch, so I disabled the boot flag on the partition to boot into android. I then shut it down, whereupon it will not boot up again. Nothing happens when pressing and holding power or volume down; no LED when charging.

Would flashing a custom/stock ROM be able to restore my phone to a usable state without losing any user or app data, such as Whatsapp/Contacts? It is not detected by adb or fastboot on Mint or Arch.

So we are talking about hard bricked Snapdragon S1 right? I am afraid this device is not recoverable because it is too old. Search for Qualcomm HS-USB QDLoader driver and Testpoint/EDL Mode. Find a flash tool (for example QPST) and a stock ROM for your device. I don't know how it works for Qualcomm devices, but for Mediatek devices it is possible to flash ROM without losing data

https://forum.xda-developers.com/showthread.php?t=2442917
https://www.youtube.com/watch?v=abzUMeVvlr8
https://www.youtube.com/watch?v=r7ewnsWVm34
https://forum.xda-developers.com/showthread.php?t=3748946
https://android.stackexchange.com/questions/210156

@alecxs Although I haven't yet tried it, thankyou for your research. I would therefore like to award you the bounty, so please put an answer so that I can do that.

For booting from MicroSD card you need to heavily modify your ROM. The android boot partition is not like a PC BIOS. You need the bootloader to look at mmcblk1 instead of mmcblk0 which is hard-coded in various system files.
(for more information refer to Irfan Latif's documentation for QMobile Z8 on forum.xda-developers.com)
If your phone does not boot into fastboot mode it is hard bricked. Most devices have a emergency download mode from where you can repair your bootloader and flash ROM. For Qualcomm devices it is the EDL mode which can be reached via EDL mode cable/dongle or with a testpoint on the PCB circuit board.
For your old Xperia device you can use Androxyde Flashtool
For other Qualcomm devices use QPST
For MediaTek devices use SP Flash Tool


text:
Which Android system file(s) should I change to connect only to specific Wi-Fi hotspots
I would like to make change in some file under the root so that Android on my device be able to connect only to specific Wi-Fi hotspots by their names and be disable to connect to all others hotspots. I mean to specify a list of the allowed hotspots in a file. I'm interested only in changing a file or files under the root and not in a program/app or changing of settings.
Which file should I change and how to?
If I make my device rooted, then add specific networks in data/misc/wifi/wpa_supplicant.conf and then switch update_config to 0, new networks are not added to the file, OK. But I still can connect to any network by typing its password manually. So how to disable this? Or how to change graphic interface to be disable to type the password manually?
ps. It's not a duplicate of Only connect to certain Wi-Fi networks

IMHO manipulating the device or it's configuration is the wrong way. Instead you should use the existing functionality in a creative way. What you want to achieve is e.g. very similar if you set-up a VPN server that is only accesible using the "allowed Wifi" network. Then set-up this VPN as "Always-on VPN" (should also be posible to set via Device Admin API/MDM solution). The device can now connect to any Wifi network but no data can be transmitted because the connection to teh VPN server is missing.

@Robert I need only a way which can be set up under the root, there is a reason


text:
How do I connect a Samsung Original Stylus Touch S Pen to a Samsung Galaxy Tab 4?
I recently bought my wife a new tablet - she is an artist and is looking to draw on the new screened tablet.  I also got her a pen so that she could do this.
The Tablet I got her was a Samsung Galaxy Tab 4 and the pen I got her was a Samsung Original Stylus Touch S Pen for Samsung Galaxy Note 4.
Is there any way for me to connect this pen to the tablet? Or do I need to get a different pen?

Nope.
A Samsung Original Stylus Touch S Pen for Samsung Galaxy Note 4 will not work on a Samsung Galaxy Tab 4
The Samsung Galaxy Tab 4 has a capacitive digitizer; not an active digitizer that the Samsung Original Stylus Touch S Pen requires.
This review states the issue; bold emphasis is mine:

The S Pen is an inductive stylus. The display on the Note has what's called an active digitizer under the glass. When the S Pen gets close to the screen, the magnetic field of the active digitizer induces a current that powers its internal circuitry. Power is passed here just like a wireless charging mat and phone that supports its work, it's just not inducing nearly as much power.

And this too; again bold emphasis is mine:

This is far more accurate than a capacitive stylus could ever be. It's why the S Pen won't work as a stylus on any other phone — it's not an electrical conductor. It's also why the S Pen, or Apple Pen, or Pixel Pen, or Surface Pen, etc. work so much better than a "regular" stylus.

Thank you - it seems I made the mistake of not realizing that a "Galaxy Note" is a smartphone, not a tablet.  Looks like we'll have to return the pen I got and purchase one that works with the Galaxy S4 - Which also explains why this one was much less expensive than the others I saw when browsing before.


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Turn off the prompt asking "You usually dismiss these notifications. Keep showing them?"
I often dismiss notifications from my home screen by swiping them. For example, I collaborate through google docs a lot, and get updates on when a document has changed. I like knowing when this happens, but often don't need to see the change itself so I just dismiss the notification by swiping. However, almost every batch of notifications I do this with, I get prompted with:
"You usually dismiss these notifications. Keep showing them?"
It interrupts me being able to dismiss notifications. And I get asked this constantly even after selecting "Keep showing".
How can I prevent these "You usually dismiss these notifications. Keep showing them?" notifications from appearing?


text:
How can Android be made to stop showing Google Contacts information?
How can Android be made to stop showing Google Contacts information? The title is sufficient to describe the problem.

One way is to prevent turn off the "Contact Sync" off
Goto Settings -> Goto Sync -> Select Google -> Select the Google Account email id if you have multiple accounts logged in.
Uncheck the Contacts so that it would not sync.

Now open Contacts App and open Settings of Contact app. Select Hide Incomplete Numbers (As most google synced contact would have only email id not numbers so they will be hidden)
That's how I guess it can be achieved


text:
Can I flash update.zip of titanium backup to non-rooted device
I was searching for an answer but I couldn't find any explanation if I'm able to flash update.zip of Titanium backup to non-rooted device.

Only if that unrooted device has an open/custom recovery, like [tag:twrp].

I adb sideloaded update..zip through twrp and I got bootloop, then sideloaded Magisk and sideloaded update.zip again and it fixed. So, don't you think it has to be rooted or this is the problem of my phone?

make sure the issue is not related to secure boot https://source.android.com/security/verifiedboot/dm-verity

TWRP has root access. And to what @alecxs wrote: that would explain why flashing Magisk solved it (Magisk does deal with dm-verity, as I know first-hand from one of my devices).


text:
Play a video on a TV over HDMI without DEX experience
I see there are two options on how to connect my S9 to a TV over HDMI: dex and screen mirroring. Neither of them quite fits what I want to do.
I'm coming from the iPhone and I want to do the same as there - use a tv only when a video is playing. E.g. I'm browsing web on my phone as usual but once I start a video I have a choice where to run it on the local phone screen or on the connected screen.
Full dex experience is just too much hassle and looks like overkill for this, not all the apps support it and sometimes there are minor issues with fullscreen players. While screen mirroring is even worse, works only with phone display on and adds black bars twice horizontally and vertically, I believe it's because screen ratio of S9 does not match my TV screen ratio 16:9

On Android the common way to play a video on a TV  is using Google Chromecast. Direct connections via USB/MHL/HDMI are not available on every device therefore the support is not standardized and hence not tested/considered by every app developer.

@Robert so does it support scenario I described? Or will it be only screen mirroring again?

The video stream only is transmitted only, if the sending app supports the Google Cast protocol. Otherwise only screen mirroring is used. See Wikipedia for details.


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Missing recovery mode on Android?
I can't hard reset my Android phone it seems like my recovery mode is missing what should I do to make it back to normal or default? I already tried to perform hard reset but it only reboot to menu.
My phone is O+ 8.38z
Android version 5.0
It is still working
But i can't access fastboot and recovery mode

Welcome Android Enthusiasts! What is your phone model and Android version?

Unfortunately, nobody can help you without any information about phone model, android version, phone state (is it working? reason for factory reset?) what exactly you have tried (steps to reproduce?) Why do you think recovery mode is missing, are there any error messages? What menu (picture?)

I already edited my question

https://www.quora.com/How-do-I-hard-reset-an-O+-3-38z-android-phone-easily there is one extra step required after selecting recovery mode


text:
Factory reset, will the os revert?
Hi I just purchased an Android phone that came with Android Oreo. It's replacing a phone that had Android Pie. Shortly after I set up the new Android Oreo phone It upgraded to Android Pie, but because the old phone was on a newer version of the operating system than the new phone when I did the initial set up none of my system backups were restored to the new phone when I was setting it up.
I'm thinking of doing a recovery mode or a factory reset on the new phone to see if it will bring over my backups and I'm wondering if this phone will revert to Android Oreo or if it will restore to Android Pie which would then restore my backup

what kind of backup?

Backup from Settings -> System -> Advanced -> Backup

A factory reset deletes all the userdata that has been stored by the user and apps, including your personal files in internal storage.
A factory reset does not make any changes to the system and boot partition (where the underlying OS is stored) or any other non-userdata partition. During a system update, it is mostly the boot and system partition which gets updated and the update doesn't keep the earlier state of Android saved, so a new update overwrites the earlier updates.
In short, a factory reset wouldn't bring your device back to Android Oreo anymore. If the backup was stored in the cloud, the restore may be triggered during Setup Wizard post the factory reset so you can try that.

Actually, the new A/B updates can be an exception: with those, the updated set of partitions is marked as bootable once the device has established that the update was successful. It might be possible to mark the older set as bootable, and thus boot Oreo.


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Vysor app isn't working for chrome on windows 7
I referred this site to install and run vysor app but it turns out that it needed a graphic card instead of using integrated graphic cards on my windows 7
there was solution on how come over this error
but that solution was only for the windows 10 users to turn on multiple displays and that option isn't available in windows 7
help me please

https://github.com/koush/vysor.io/issues/124 it is related to WebGL i never got it work. but there is a nice alternative https://www.xda-developers.com/scrcpy-control-android-on-pc

Yes, scrcpy is a very good alternative. I recently tried it. Teamviewer also works fine but requires internet.


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How to fix Hangouts not working for one gmail account
My Hangouts had two email accounts associated with it. One stopped working. I tried deleting and re-installing Hangouts. I tried deleting and reinstalling the email account that was not working with Hangouts.
Now when I try to add this second email account to Hangouts, I get the error message that the account already exists on the device.
I did delete that email account and before adding it via the phone's accounts manager, I tried to add it from Hangouts. It then added it as an email account but not associated with Hangouts.

Sorry - I got it fixed. I tried deleting the email account and then before re-adding it, I restarted the phone. Then when I added the account to Hangouts it worked.


text:
Factory reset (Software repair) Sony Xperia XCompact (and all other Xperia smartphones) that have software issues like a boot loop
I'd like to share how you can reset your Xperia even if it doesn't boot (start) anymore! It not only helps to break a boot loop, it also helps to unlock the phone if you forgot your smartphone lock credentials. Of course, your data on the phone will be erased.
I will answer my question right away which is allowed by stack exchange rules (at least it used to be)

Sony has gotten really good with their software suppport for their Xperia line up. Their software actually works to get bricked phones alive again.
The method I describe below doesn't require an unlocked bootloader and doesn't unlock it as well. Which is a good thing since you keep your warranty and you won't loose DRM rights that are for example used for the noise reduction software of your Xperia camera.

Your phone should be charged at least 80%.
Keep your smartphone turned off and disconnected until I say so! Otherwise it won't work.
Get the Xperia Companion: https://support.sonymobile.com/de/xperia-companion/

Now you can connect your smartphone to your computer while pressing volume down:


text:
Android "Nearby" ( set up nearby device ) - "No devices Found"
trying to migrate over from  1 mobile to other . Older is on 7.0 and newer is 9.x aka Pie.

Both devices have bluetooth and wi-fi turned on. In fact one sees the other on a bluetooth scan and they are paired.

Its just that the nearby service (?) of whatever its called that is used  for setting up a new device just doesn't do its job.
I initiated  simultaneously from both phone - the "find nearby devices" beacon...none of the phones "found " each other . I repeated the same separately- No avail.

Why is this happening and what does it take for this stuff to run correctly ?


text:
fastboot doesn´t see device but device manager & windows does
I am trying to unlock the bootloader of my Umidigi F1.
ADB works, recognizes my phone but once I get into fastboot mode, fastboot devices does not display and devices.
I did install all the drivers and Windows itself does see an Android device,
and device manager does not show any unknown devices.
I have attached images of the devices Windows and the Device Manager find once I connect my phone in fastboot mode.

Possible duplicate of Fastboot doesn't see nexus 6p


text:
where can i get app back that opens a tab for all my apps?
My smartphone was open in my pocket and the application that opens the tab for my all apps disappeared. Now i can open apps that are not on the home screen just through the play store.
phone sony xperia xz2 compact, android pie 9

Usually, there's always a way to open the app menu from the home screen (e.g. by dragging from the bottom of the screen). However, without much information, it's almost impossible to guess the cause. At the very least, could you provide the phone model, the Android version, and whether you're using 3rd-party launcher or not? Additionally, a screenshot of the problem might help.

Not my phone but I drew a red circle around what's missing.  Can I get that somewhere back? Without it i can't find any others means to launch my apps tha play store. (phone sony xperia xz2 compact, android pie 9)

thanks very much Andrew T. looks like i can open that tab by dragging from the bottom of the screen.


text:
Camera folder displayed as empty, but contains 20GB data
My Lenovo Moto G5 Plus' internal storage ran full, and now there appears to be a problem with the photos that are saved on its internal storage. The internal DCIM/Camera folder is displayed as empty when I

open the gallery app
open the folder with the Solid Explorer app
open the folder on my PC (file transfer mode as well as PTP mode).

BUT the app "DiskUsage" says that the folder has got a size of 20GB, and luckily I was able to do a backup of its contents using adb pull.
What can I do to make the content visible for the phone again? Using a scanning app like "SD Card scanner" did not help.

Try clearing data of Media Storage app: https://android.stackexchange.com/a/209119/218526

delete .nomedia files


text:
How do you fix "adb locksettings not found"?
I have a J3 Eclipse running Android 7.0 plugged into my computer and try to view the locksettings by typing adb shell locksettings. This returns /system/bin/sh: locksettings: not found. How can I fix this?

I tried updating the phone to Android 8.1 and 9.0 and the issue seems to have been solved in both releases. If you're facing this issue try updating the OS and see if the problem still persists.


text:
How to determine which app is causing vibration?
I have a Moto G6 Play that vibrates like it is getting notifications but it's not. The vibration is inconsistent and seems random so I would like to know if there is a logcat or something I can run to log which app is calling the vibration so that I can shut it off? The same thing happens on my wife's phone, same model, and it does my head in. The device is running Android 9.

In addition to the dumpsys method explained in the other answer, you can use Android's hidden (kind of) permission manager appops to get recently allowed vibrator requests, e.g. in last minute. From adb shell:
for pkg in $(pm list packages | sed 's/package://')
do
    echo "$pkg $(appops get $pkg VIBRATE)" | grep 'time=+[0-9]*s'
done

pm is the package manager which lists all installed packages. appops determines when last time each package made a vibration request and if it was allowed or rejected.
Result can be further filtered by piping output through awk '{printf "%-12s%-20s%s\n",$3,$4,$1}':
allow;      time=+15s659ms      com.termux
allow;      time=+6s458ms       com.google.android.inputmethod.latin

Termux made a vibration 15 seconds back. Also the request can be denied:
~$ appops set com.termux VIBRATE deny

Now the output will be like this:
deny;       time=+9s500ms       com.termux
allow;      time=+6s392ms       com.google.android.inputmethod.latin

And a shameless self-promotion. If not comfortable with CLI, you can use my open-source app Permission Manager X to get and set AppOps:

To clarify, will I need root access to run that command or will an up to date adb installation suffice? Thanks again.

@Badger all commands work without root on adb shell, but not on a terminal emulator app.

The next time your device vibrates, connect it to a PC with adb already setup, and issue this command:
adb shell dumpsys vibrator

In the output, along with the pattern of vibration  you would be able to see the UID and package name of the app that caused the vibration in the device recently. For example, in my OnePlus 6 (Android 8.1.0) device it showed this output:

Previous vibrations:
  , startTime: 95325556, effect: Waveform{mTimings=[0, 250], mAmplitudes=[0, -1], mRepeat=-1}, usageHint: 5, uid: 10122, opPkg: com.textra
  , startTime: 95346005, effect: Waveform{mTimings=[0, 250], mAmplitudes=[0, -1], mRepeat=-1}, usageHint: 5, uid: 10122, opPkg: com.textra
  , startTime: 95428005, effect: Waveform{mTimings=[0, 250], mAmplitudes=[0, -1], mRepeat=-1}, usageHint: 5, uid: 10122, opPkg: com.textra
  , startTime: 95516412, effect: OneShot{mTiming=50, mAmplitude=-1}, usageHint: 0, uid: 1001, opPkg: com.android.incallui
  , startTime: 95572994, effect: Waveform{mTimings=[0, 250], mAmplitudes=[0, -1], mRepeat=-1}, usageHint: 5, uid: 10122, opPkg: com.textra
  , startTime: 96868723, effect: Waveform{mTimings=[0, 250], mAmplitudes=[0, -1], mRepeat=-1}, usageHint: 0, uid: 1000, opPkg: android
  , startTime: 97144598, effect: OneShot{mTiming=200, mAmplitude=-1}, usageHint: 0, uid: 10130, opPkg: com.phonepe.app
  , startTime: 97187986, effect: OneShot{mTiming=200, mAmplitude=-1}, usageHint: 0, uid: 10130, opPkg: com.phonepe.app
  , startTime: 98229901, effect: Waveform{mTimings=[0, 300], mAmplitudes=[0, -1], mRepeat=-1}, usageHint: 0, uid: 10133, opPkg: com.arlosoft.macrodroid

The string next to opPkg: is the package name of the app that caused the vibration at a certain time. The list is in chronological order with the most recent entry at the bottom. To get the app's name out of the package name, see my answer here.

On Pie I get human readable time: startTime: Aug 10, 2019, 2:05:20 AM, effect: Prebaked{mEffectId=0, mEffectStrength=1, mFallback=true}, originalEffect: null, usageHint: 13, uid: 10151, opPkg: com.google.android.inputmethod.latin


text:
Should the Dalvik cache on Android phones be cleared periodically?
Recently, I rooted my phone (Samsung Galaxy On7, Android 6.0.1) using Magisk systemless root using TWRP. After the flashing was over, I also cleared the Dalvik cache, not knowing that this was not necessary. When I rebooted the phone, it took a long time to boot. It was showing, "Optimizing apps". I thought I had cracked the phone up and it was a boot loop. But later I found that everything was fine. In addition, clearing of the Dalvik cache actually freed up the internal memory by about 1GB.
I read on Stack Overflow that Dalvik cache is actually the optimized dex files that the dex compiler builds to ensure the smooth running of applications. Now, the last official update to this phone was back in April 2018. Is it possible that the phone retained the cache of all apps since then, including the ones I had uninstalled? It seems so, otherwise how could I recover about 1GB of memory simply by clearing the Dalvik cache?
If I am correct that clearing the Dalvik cache freed up space, does it make sense to clear the Dalvik cache periodically, say annually, so as to prevent misuse of the "precious" internal memory?

If you have the habit of removing apps on a regular basis, then you can clear it regularly. Once a year or once every 6 months should be fine. If you have root, then you can use Titanium backup as stated on this answer to remove dex files not link to apps.

Starting with L or M, /data/dalvik-cache/ is only used for system apps, not for user apps. User apps' ART cache is located in /data/app/<PKG>/oat/ which should be deleted with app uninstallation. That's what my understanding is.

@IrfanLatif Android L


text:
Android 8 delayed notifications
Every once in a while my device get "stuck" - I send an SMS or Email, and they are received only after 10 minutes or later. The device can be "stuck" even when the phone is on, and running other apps.
I tried installing Push Notification Fixer apps, but they do not help.
When I send the test and the phone is not "stuck", I get a notification after about 10 seconds.
However, I do receive notifications for Google Voice and WhatsApp when phone is in "stuck" phase, so it does seem app specific issue. Also I have noticed that these 2 apps have permission receive data from Internet , which the Gmail app does not. Seems to be related to what type of push notification is used. see documentation.
Also I noticed the Google Play Store is unable to install/uninstall apps in this "stuck" phase.

The answer doesn't work lol. Btw, there's no way to fix delayed notifications on my phone. Some device manufactures have aggressive battery optimization changes that cause delays or even nothing may happen so no setting may work. The actual answer may be to get a different phone from different manufacturer sadly. And yes, Google introduced different ways, its possible one way or another may cause different reaction.

It does not make sense to block some functions when the phone is on and running other apps, which is already battery consuming.

Here's a list of things you can try:

Make sure you haven't disabled the app by force quitting on it
Make sure power saving mode isn't on
Check Data usage to see if Background Data is enabled for the App
Turn off battery optimization from Battery Usage option for the App
Make sure that there isn't any third party overlayer that you've utilized which is utilizing the app sync permissions ( certain launchers/ addons may do so)
Clear cache for that particular App
Factory reset the Google app by selecting the Uninstall updates option
Install this app and set your heartbeat rate to 5 minutes. It's a quick fix for the issue. It's most probably a network driver issue which the company needs to patch up and in the meantime, you can use this app to ensure normal functionality

Tried all that. doesn't help.

Then try installing the app that I've linked. It's a network framework issue and requires a company side fix. Also try to see if you can send them a ticket regarding your complain

Note: Disabling the battery optimization may not have an immediate effect. I had the case where I had to reboot the phone before the setting was applied and the app finally worked as expected.

You should probably do the "wipe system cache" of your phone. That might help (check out the steps online)

Try this by order:

If you have any Power Safe App - turn it off
If you have any Power Safe Mod - turn it off and test will it works
Check for Wi-Fi sleep - go to Settinings >Connection > Wi-Fi >
Advanced > ensure "Keep Wi-Fi on during sleep" option is set to Always
Check for properly syncing data in the background - Settings >  Data Usage > make sure "Restrict app background data" feature is turned off
Try to delete Cache of app (SMS, email, gmail etc.)
With this app which you try set it to maximum amout of time.

Tried all that. Except clear cache. I'll try and will report if fixed. thanks

Ok still doesn't work.


text:
How do I disable the missed phone call notification light?
The green flashing light whenever I miss a call is really annoying.  I'd like to turn that off while keeping the purplish voicemail indicator light.  I'm not finding a clear way to do it in the phone app nor in general settings.  The similar questions I've seen have actually been about the call log or other notifications which are not the same.

it is impossible to change it in setting(you can only completly turn it off or on). But you have some apps for that. For most of them,you need root. But I found this one in link(article about it) for which you do not need it. It is Led Blinker(avaiable in Google Play Store)You have lite and pro version, but lite should be more than enought.
LINK WITH INSTRUCTIONS HOW TO USE IT: https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.guidingtech.com/23212/customize-disable-led-notifications-android/&ved=2ahUKEwig0IfSvvbjAhVG2KQKHSndB48QFjASegQIBxAB&usg=AOvVaw3YIcmp9EWQpzvCGuaCwlLU&cshid=1565378157374

OK, how can I turn it off completely in settings?

Hello. Can you link instructions from that link right here into the answer? Links having instructions/usage are terrible to rely upon as they can expire anytime thus robbing the usefulness of a link-dependent answer.

Link is just annex to answer and it is not important for question.

you need to go into  settings > accessibility > Hearing > Flash Alerts - and turn it off.


text:
What is the "code" after the app package name in /data/app/?
Just by curiosity, since I wasn't able to find an answer after googling, do you know what are these "codes" after the packages names of my apps in /data/app/…?
This number is neither in androidmanifest.xml, nor in cert.sf, nor in manifest.mf (inside the meta-inf folder).
For example the package name of Clash of Clans is followed by the "code": com.supercell.clashofclans-Bd6GIb47XTzpL16jgR1kZA==

See also the identical question in Stackoverflow.com.

That's a random string appended to apps installation path in order to force developers don't hard-code paths in apps, instead use proper APIs.
Quoted from Android 8.0 Behavior Changes:

You can no longer assume that APKs reside in directories whose names end in -1 or -2. Apps should use sourceDir to get the directory, and not rely on the directory format directly.

Thanks for the explaination. But why don't they want people to hard-code the path, is it a security?

@sebastienfinor you are right, also they have put this point under Security heading.

@sebastienfinor The commit message that introduces these changes says: "This prevents apps (both normal and ephemeral) from learning what
applications are installed by checking for the existence of
/data/app/com.example.package-1."