How can I automatically answer a call to an Android device with a busy signal?

Question

I'm developing a toy Android app: one of its functions is that it looks at incoming calls and if the calling number is in a blacklist, automatically closes the call. I'm having a problem making that work. I'm referencing android.telephony.TelephonyManager to close the incoming call.

Is there a way to let the caller think that I'm in another call (busy)? Or to let the caller think that my phone is off or has no reception?

Answer 1

use airplane mode

android.provider.Settings.System.putInt(mcontext.getContentResolver(), android.provider.Settings.System.AIRPLANE_MODE_ON, 1);
Intent intent = new Intent(Intent.ACTION_AIRPLANE_MODE_CHANGED); 
intent.putExtra("state", 1); 
mcontext.sendBroadcast(new Intent("android.intent.action.AIRPLANE_MODE")); 
mcontext.sendBroadcast(intent); 
try {
    Thread.sleep(500);
        }
    catch (InterruptedException e) {
        }
android.provider.Settings.System.putInt(mcontext.getContentResolver(), android.provider.Settings.System.AIRPLANE_MODE_ON, 0);
intent.putExtra("state", 0); 
mcontext.sendBroadcast(new Intent("android.intent.action.AIRPLANE_MODE")); 
mcontext.sendBroadcast(intent);