Block calls without ringing I've a rooted phone (Samsung Grand Prime, without CM, just the STOCK Rom), and what I want to know if it's possible with Android 5.0 phone or newer to block calls without ringing. By default, the Call Rejection List just wait 1 ring before reject the call... All blocking applications has to wait 1 ring too before blocking the call, which is logical. But the main drawback of this is that people could suppose if they're blocked.

I've tried two applications : RBC &amp; Call Master that do this stuff (they need root permissions) but each shutdown the mobile network and don't seem to work well witht Lolipop or newer.

I've read somewhere that since Gingerbread, Google don't allow applications to get the MODIFY_PHONE_STATE, so just only apps that need root could do it.
If you wish to not be annoyed by unknown callers, try the following (Android phone) solution.


Open Settings
Select Sounds and vibration
Select Ringtone
Select Silent (this will set your default ringtone to silent all incoming calls)
Go to Phone app
Select Contacts
For each Contact that you DO want to receive calls from do the following:


Select the individual
Select the “i” info 
Select “Edit” at bottom of screen
Scroll down until you see and select “View more”
Scroll down until you see and select “Ringtone”
Choose a ringtone other than “Default ringtone”
Press the Back button to return to previous Edit screen
Select Save at bottom of screen
Return to Contacts, repeat a thru h for each contact for whom you DO want to receive calls
If you add New Contacts, remember to follow 1 thru 8 to set their ringtone to something other than the default.



This method will allow all callers to leave a voicemail and not know they have basically been screened.  You can always review your calls using steps 1 thru 8 you can those callers you may have inadvertently missed.