About Blokka
Blocks calls
Deletes blocked calls from the call log
No missed-call notifications
No voicemail messages
No log of blocked calls
Block list backed up to file
No ads
I made this app after being very disappointed with a very popular one that didn't work for me. All it did was stop the phone ringing. I could still see the incoming-call screen. I then got a missed call notification. I also saw the number in my phone's call log and the app's blocked call log.
When I block a number, I want it to be history. So having written some apps, I decided to write my own call blocker. So I wrote Blokka. My intention all along was to make it extremely simple. You can't get simpler. You add a number to block, and that's it. You can add a number from the call log or you can manually enter one by typing it. Any number added to the block list can be deleted, in case you added it by mistake, for example.
When you open the app, a service runs in the background, listening out for calls to block. It compares incoming calls with the numbers you have entered on your block list, if there's a match, Blokka blocks the call then removes it from the call log. The service continues to run when you close the app. It also starts automatically when you restart your phone.
The block list (containing the numbers you've blocked) is automatically backed up to a file. You can make a copy of this file and import it into another device, such as a new phone.
You won't get bombarded with ads. Presently there aren't any ads on the app, and if I include any they will be very unobtrusive.
Permissions
For Android 4.4 and above, permission is required to read from and write to the call log. This is to allow you to pick numbers from your call log to block and to allow Blokka to delete blocked calls from the call log.
The permissions for Android 4.3 or earlier, state that Blokka can read from and write to your contacts. Blokka doesn't read from or write to your contacts. That permission is required because you can't specify permission to read the call log on those versions and have to get permission to read the contacts instead.
You also have to grant permission for Blokka to read the device state and identity. This is just so Blokka knows when there's an incoming call.
The permissions also state that Blokka can directly call phone numbers. It doesn't do this but it needs that level of permission to end a call, which it does do.
For Android versions before 4.4 KitKat, permission is required to write to external storage. This is to write the block list backup file. For newer versions, this permissionis granted automatically.