Android Keep Broadcast Receiver Running After Application Exit

In some cases, you may need to create a broadcast receiver that can still run in the background after the Android app exits. This example will just tell you how to do that using a broadcast receiver and Android service object.

1. Screen On Off Broadcast Receiver.

Below java files are the example project used files.

D:\WORK\DEV2QA.COM-EXAMPLE-CODE\ANDROIDEXAMPLEPROJECT\EXAMPLE\APP\SRC\MAIN\JAVA\COM\DEV2QA\EXAMPLE\BROADCAST
├─activity
│  └─forceoffline
│          ScreenOnOffActivity.java
│
├─receiver
│  └─forceoffline
│          ScreenOnOffReceiver.java
│
└─service
    └─forceoffline
           ScreenOnOffBackgroundService.java

First, we will create a broadcast receiver that can listen and process the Android screen on/off broadcast event as below.

As you can see, we will check the broadcast action value and log debug messages based on that value in the broadcast receiver’s onReceive() method.

ScreenOnOffReceiver.java

package com.dev2qa.example.broadcast.receiver;

import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;

public class ScreenOnOffReceiver extends BroadcastReceiver {

    private final static String SCREEN_TOGGLE_TAG = "SCREEN_TOGGLE_TAG";

    @Override
    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if(Intent.ACTION_SCREEN_OFF.equals(action))
        {
            Log.d(SCREEN_TOGGLE_TAG, "Screen is turn off.");
        }else if(Intent.ACTION_SCREEN_ON.equals(action))
        {
            Log.d(SCREEN_TOGGLE_TAG, "Screen is turn on.");
        }
    }
}

2. Register And Unregister ScreenOnOffReceiver In Activity.

Now we will create an activity and register the ScreenOnOffReceiver object in it’s onCreate() method, and unregister the receiver in it’s onDestroy() method as below.

ScreenOnOffActivity.java

package com.dev2qa.example.broadcast.activity;

import android.content.IntentFilter;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;

import com.dev2qa.example.R;
import com.dev2qa.example.broadcast.receiver.ScreenOnOffReceiver;

public class ScreenOnOffActivity extends AppCompatActivity {

    private ScreenOnOffReceiver screenOnOffReceiver = null;

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

        setTitle("dev2qa.com - Keep BroadcastReceiver Running After App Exit.");

        // Create an IntentFilter instance.
        IntentFilter intentFilter = new IntentFilter();

        // Add network connectivity change action.
        intentFilter.addAction("android.intent.action.SCREEN_ON");
        intentFilter.addAction("android.intent.action.SCREEN_OFF");

        // Set broadcast receiver priority.
        intentFilter.setPriority(100);

        // Create a network change broadcast receiver.
        screenOnOffReceiver = new ScreenOnOffReceiver();

        // Register the broadcast receiver with the intent filter object.
        registerReceiver(screenOnOffReceiver, intentFilter);

        Log.d(ScreenOnOffReceiver.SCREEN_TOGGLE_TAG, "onCreate: screenOnOffReceiver is registered.");

    }

    @Override
    protected void onDestroy() {
        super.onDestroy();

        // Unregister screenOnOffReceiver when destroy.
        if(screenOnOffReceiver!=null)
        {
            unregisterReceiver(screenOnOffReceiver);
            Log.d(ScreenOnOffReceiver.SCREEN_TOGGLE_TAG, "onDestroy: screenOnOffReceiver is unregistered.");
        }
    }
}

Below is the layout XML file for the above activity.

activity_screen_on_off.xml

<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="left"
    android:text="Press power button to turn on / off screen and see log message in android monitor."
    android:textSize="20dp"
    android:layout_marginTop="20dp"/>

Run the above activity in the below steps.

When starting the activity, there is a log message that says the broadcast receiver has been registered in the activity’s onCreate() method.

Press the power button to turn off the screen.

Press the power button again to turn on the screen.

You can see log data in the Android monitor console for the above steps.

Type the back menu to exit the activity. You can see the broadcast receiver is unregistered in the activity’s onDestroy() method also.

Press the power button to execute steps 2, 3 again, but there is no log data printed in the Android monitor console.

3. Register And Unregister Broadcast Receiver In Android Background Service.

When you register the broadcast receiver in the Android activity class, it will be stopped after the activity exits.

To resolve this problem, we will create an android service object, and register and unregister the broadcast receiver in the service object.

Because the Android service object will still run in the background after the activity exit, the broadcast receiver will still run also after the Android app exit.

3.1 Create Android Service Class.

3.1.1 Create A Java Class That Extends android.app.Service.

ScreenOnOffBackgroundService.java

package com.dev2qa.example.broadcast.service;

import android.app.Service;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.IBinder;
import android.support.annotation.Nullable;
import android.util.Log;

import com.dev2qa.example.broadcast.receiver.ScreenOnOffReceiver;

public class ScreenOnOffBackgroundService extends Service {

    private ScreenOnOffReceiver screenOnOffReceiver = null;

    @Nullable
    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public int onStartCommand(Intent intent, int flags, int startId) {
        return super.onStartCommand(intent, flags, startId);
    }

    @Override
    public void onCreate() {
        super.onCreate();

        // Create an IntentFilter instance.
        IntentFilter intentFilter = new IntentFilter();

        // Add network connectivity change action.
        intentFilter.addAction("android.intent.action.SCREEN_ON");
        intentFilter.addAction("android.intent.action.SCREEN_OFF");

        // Set broadcast receiver priority.
        intentFilter.setPriority(100);

        // Create a network change broadcast receiver.
        screenOnOffReceiver = new ScreenOnOffReceiver();

        // Register the broadcast receiver with the intent filter object.
        registerReceiver(screenOnOffReceiver, intentFilter);

        Log.d(ScreenOnOffReceiver.SCREEN_TOGGLE_TAG, "Service onCreate: screenOnOffReceiver is registered.");
    }

    @Override
    public void onDestroy() {
        super.onDestroy();

        // Unregister screenOnOffReceiver when destroy.
        if(screenOnOffReceiver!=null)
        {
            unregisterReceiver(screenOnOffReceiver);
            Log.d(ScreenOnOffReceiver.SCREEN_TOGGLE_TAG, "Service onDestroy: screenOnOffReceiver is unregistered.");
        }
    }
}

3.1.2 Add Service Xml Tag In AndroidManifest.xml File.

AndroidManifest.xml

<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.dev2qa.example">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        
        <activity android:name=".broadcast.activity.ScreenOnOffActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>

        <service android:enabled="true" android:name=".broadcast.service.ScreenOnOffBackgroundService" />
    </application>

</manifest>

3.1.3 Change Activity Java Code To Below.

Please notice the Java code that starts the service object.

Intent backgroundService = new Intent(getApplicationContext(), ScreenOnOffBackgroundService.class);
startService(backgroundService);

ScreenOnOffActivity.java

package com.dev2qa.example.broadcast.activity;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;

import com.dev2qa.example.R;
import com.dev2qa.example.broadcast.receiver.ScreenOnOffReceiver;
import com.dev2qa.example.broadcast.service.ScreenOnOffBackgroundService;

public class ScreenOnOffActivity extends AppCompatActivity {

    private ScreenOnOffReceiver screenOnOffReceiver = null;

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

        setTitle("dev2qa.com - Keep BroadcastReceiver Running After App Exit.");

        Intent backgroundService = new Intent(getApplicationContext(), ScreenOnOffBackgroundService.class);
        startService(backgroundService);

        Log.d(ScreenOnOffReceiver.SCREEN_TOGGLE_TAG, "Activity onCreate");
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        Log.d(ScreenOnOffReceiver.SCREEN_TOGGLE_TAG, "Activity onDestroy");
    }
}

Run the example again, you can see the below picture. From the Android Logcat output, we can see the broadcast receiver still running after the Android app exits.