How to add a popup window over an Android native incoming call screen like the Truecaller Android app

My broadcast reciver

1. package com.example.popwindowonincomingcallscreen; 
2. import java.util.concurrent.Executors; 
3. import java.util.concurrent.ScheduledExecutorService; 
4. import android.content.BroadcastReceiver; 
5. import android.content.Context; 
6. import android.content.Intent; 
7. import android.telephony.TelephonyManager; 
8. import android.util.Log; 
9. public class IncomingBroadcastReceiver extends BroadcastReceiver { 
10. @Override 
11. public void onReceive(Context context, Intent intent) { 
12. Log.d("IncomingBroadcastReceiver: onReceive: ", "flag1"); 
13. String state = intent.getStringExtra(TelephonyManager.EXTRA_STATE); 
14. Log.d("IncomingBroadcastReceiver: onReceive: ", state); 
15. if (state.equals(TelephonyManager.EXTRA_STATE_RINGING) 
16. || state.equals(TelephonyManager.EXTRA_STATE_OFFHOOK)) { 
17. Log.d("Ringing", "Phone is ringing"); 
18. Intent i = new Intent(context, IncomingCallActivity.class); 
19. i.putExtras(intent); 
20. i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK); 
21. i.addFlags(Intent.FLAG_ACTIVITY_SINGLE_TOP); 
22. Wait.oneSec(); 
23. context.startActivity(i); 
24. } 
25. } 
26. } 

An the activity which I am calling

1. import android.app.Activity; 
2. import android.os.Bundle; 
3. import android.telephony.TelephonyManager; 
4. import android.util.Log; 
5. import android.view.View.MeasureSpec; 
6. import android.view.Window; 
7. import android.view.WindowManager; 
8. import android.widget.TextView; 
9. public class IncomingCallActivity extends Activity { 
10. @Override 
11. protected void onCreate(Bundle savedInstanceState) { 
12. try { 
13. Log.d("IncomingCallActivity: onCreate: ", "flag2"); 
14. */After this line code is not executed in jelly bean only/* 
15. // TODO Auto-generated method stub 
16. super.onCreate(savedInstanceState); 
17. getWindow().addFlags(WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE); 
18. getWindow().addFlags( 
19. WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL); 
20. Log.d("IncomingCallActivity: onCreate: ", "flagy"); 
21. setContentView(R.layout.main); 
22. Log.d("IncomingCallActivity: onCreate: ", "flagz"); 
23. String number = getIntent().getStringExtra( 
24. TelephonyManager.EXTRA_INCOMING_NUMBER); 
25. TextView text = (TextView) findViewById(R.id.text); 
26. text.setText("Incoming call from " + number); 
27. } catch (Exception e) { 
28. Log.d("Exception", e.toString()); 
29. // TODO Auto-generated catch block 
30. e.printStackTrace(); 
31. } 
32. } 
33. }