MainActivity.java

// in adb shell I sent this commands for simulating dialog's appears: (Airplane dialog (https://i.stack.imgur.com/Qatww.jpg) is showing on LG G2 phone, on other phones, this dialog may not appear. )
//"settings put global airplane_mode_on 1;am broadcast -a android.intent.action.AIRPLANE_MODE --ez state true"
//"settings put global airplane_mode_on 0;am broadcast -a android.intent.action.AIRPLANE_MODE --ez state false"
//or start another my dialog-style application, like:
// am start -n "org.kinocat.goodsearcher/org.kinocat.goodsearcher.MainActivity" -a android.intent.action.MAIN -c android.intent.category.LAUNCHER
//but always topActivity = my main activity .

package org.kinocat.myapplication;

import android.app.Activity;
import android.app.ActivityManager;
import android.content.ComponentName;
import android.content.res.Resources;
import android.graphics.drawable.StateListDrawable;
import android.os.Bundle;
import android.support.v4.content.ContextCompat;
import android.support.v7.app.AlertDialog;
import android.support.v7.app.AppCompatActivity;
import android.view.View;
import android.widget.ArrayAdapter;
import android.widget.Spinner;

import java.util.List;

public class MainActivity extends AppCompatActivity {

    private Spinner spinner;
    private ActivityManager manager;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    }

    @Override
    protected void onResume() {
        super.onResume();
        android.util.Log.d("", "onResume");
    }

    @Override
    protected void onPause() {
        super.onPause();
        android.util.Log.d("", "omPause");
    }

    @Override
    public void onWindowFocusChanged(boolean hasFocus) {
        super.onWindowFocusChanged(hasFocus);

        manager = (ActivityManager)getSystemService(Activity.ACTIVITY_SERVICE);

        new Thread(){
            @Override
            public void run() {
                for (int i = 0; i < 2; i++) {
                    try {
                        Thread.sleep(1000);
                    } catch (InterruptedException e) {

                    }
                    showTopActivity();
                }

            }
        }.start();



    }

    private void showTopActivity() {
        final List<ActivityManager.RunningTaskInfo> runningTasks = manager.getRunningTasks(1);
        
        //this ugly code just for testing :) 
        int i = 0;
        for (ActivityManager.RunningTaskInfo info : runningTasks) {
            i++;
            android.util.Log.d("FreakMurderer", i + ":" + info.topActivity);
            //android.util.Log.d("FreakMurderer", i + ":" + info.baseActivity);
            android.util.Log.d("FreakMurderer", "--");
        }
        
        final ComponentName componentName = runningTasks.get(0).topActivity;
        final String className = componentName.getClassName();

        //android.util.Log.d("FreakMurderer", "className:" + className);

        if (className.equals("YOUR_EXPECTED_ACTIVITY_CLASS_NAME")) {
            // do something
        }
    }    
}