Block calls without ringing

Question

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 & 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.

Answer 1

If you wish to not be annoyed by unknown callers, try the following (Android phone) solution.

1. Open Settings
2. Select Sounds and vibration
3. Select Ringtone
4. Select Silent (this will set your default ringtone to silent all incoming calls)
5. Go to Phone app
6. Select Contacts

7. For each Contact that you DO want to receive calls from do the following:

   1. Select the individual
   2. Select the “i” info
   3. Select “Edit” at bottom of screen
   4. Scroll down until you see and select “View more”
   5. Scroll down until you see and select “Ringtone”
   6. Choose a ringtone other than “Default ringtone”
   7. Press the Back button to return to previous Edit screen
   8. Select Save at bottom of screen
   9. 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.

Answer 2

The app TrueCaller as well as a bunch of others have a block feature where it will instantly answer and hangup the call. I personally don't like TrueCaller. You can also check the setting "send to voicemail" in the contact you'd like to block. This sends them to voicemail every time.

On the other hand, if you want them to know they're blocked, why not send them a text saying that, then block them using the above techniques.