Is incoming/outgoing call screen customizable? I'm looking for a way to change the incoming/outgoing call screen (that of my Sony phone needs replacement at least because when I press a button to turn on the screen and tap the "end call" button or to see the length of the talk, the screen is turned off in a second). I've tried a couple of dialer/contacts apps and those don't actually change that screen. Moreover, the comment here suggests that this screen may be changed only on a rooted device.

Is it so? Is this screen a part of launcher? A separate app? Is rooting required to change this? Where can I grab alternative implementations? A more detailed how to is appreciated since the phone is rooted already anyway.

PS the screen I'm talking about looks similar to this:
To do so. Root the phone. Extract, and recompile these apps:

/system/priv-app/TelephonyProvider/TelephonyProvider.apk
/system/priv-app/Telecom/Telecom.apk
/system/app/InCallUiNext/InCallUiNext.apk
/system/app/telresources/telresources.apk
/system/framework/framework-res.apk


And this file also:

/system/framework/telephony-common.jar


After changing their drawable elements, return them where they were and set these permissions.

chmod 0755 for folders
chmod 0644 for files

This will work very well for you but always keep a backup of them incase something goes wrong. This is for editing the app but if the dialer is freezing after ending a call, then what you need to do is:

 1. Open Settings
 2. Click Apps
 3. Press the options icon
 4. Tap Show System
 5. Clear Data and Cache for Dialer and Telephony Provider


If still this doesn't work if you have TWRP Recovery installed:

 1. Press Wipe
 2. Advanced Wipe
 3. Check Dalvik Cache and Cache partitions
 4. Swipe to clear them
 5. Reboot System


Note: The in-call popup never changes no matter what dialer you opt for. Deleting it for example means the Telephone Service is tampered with. And you won't receive any calls. All other apps can offer adress book, blocking and dialer but on call dialing is then commanded to Telecom app which then manages the calling services and renders UI for call until the end. It offers the native service that is for calling and communicating to the phone gsm radio. All other apps can't do this. Just like in a media player, a media decoding library or a codec, so is the Telecom app essence and purpose. It is the core handler of telephony. Unless you modify it or redevelop it by code. It's one of the essential apps alongside SystemUI and Framework. That's why it won't be a walk in the park replacing it. It is integral to many system apps

This will solve your issue very well. Please let me know if it helped you