As result I have found http://androidbridge.blogspot.com/2011/05/how-to-answer-incoming-call-in-android.html
Here is solution which works on HTCs devices:
In Android 2.3.3 HTC Sensation this piece of code does not work. Reason is in 2.3.3 I found a HeadsetObserver listening for actual bluetooth plug-in event. So you need to send a Intent pretending there is a headset connected already. To fix this problem you need to send the ACTION_HEADSET_PLUG Intent before calling the above code.
So I added following code before accept call code:
Intent headSetUnPluggedintent = new Intent(Intent.ACTION_HEADSET_PLUG);
headSetUnPluggedintent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY);
headSetUnPluggedintent.putExtra("state", 1); // 0 = unplugged 1 = Headset with microphone 2 = Headset without microphone
headSetUnPluggedintent.putExtra("name", "Headset");
// TODO: Should we require a permission?
sendOrderedBroadcast(headSetUnPluggedintent, null);
so final worked code is
private void acceptCall() {
setHeadSetConnectEmulated();
Intent buttonUP = new Intent(Intent.ACTION_MEDIA_BUTTON);
buttonUP.putExtra(Intent.EXTRA_KEY_EVENT, new KeyEvent(KeyEvent.ACTION_UP, KeyEvent.KEYCODE_HEADSETHOOK));
IncomingCallActivity.this.getApplicationContext().sendOrderedBroadcast(buttonUP, "android.permission.CALL_PRIVILEGED");
}
private void setHeadSetConnectEmulated(){
Intent headSetUnPluggedintent = new Intent(Intent.ACTION_HEADSET_PLUG);
headSetUnPluggedintent.addFlags(Intent.FLAG_RECEIVER_REGISTERED_ONLY);
headSetUnPluggedintent.putExtra("state", 1); // 0 = unplugged 1 = Headset with microphone 2 = Headset without microphone
headSetUnPluggedintent.putExtra("name", "Headset");
// TODO: Should we require a permission?
sendOrderedBroadcast(headSetUnPluggedintent, null);
}
private void rejectCall() {
Intent buttonDown = new Intent(Intent.ACTION_MEDIA_BUTTON);
buttonDown.putExtra(Intent.EXTRA_KEY_EVENT, new KeyEvent(KeyEvent.ACTION_DOWN, KeyEvent.KEYCODE_HEADSETHOOK));
IncomingCallActivity.this.getApplicationContext().sendOrderedBroadcast(buttonDown, "android.permission.CALL_PRIVILEGED");
}