How to implement an Android notification action without opening the app?

This example demonstrate about How to implement an Android notification action without opening the app.
Step 1 − Create a new project in Android Studio, go to File ⇒ New Project and fill all required details to create a new project.
Step 2 − Add the following code to res/layout/activity_main.xml.
<? xml version = "1.0" encoding = "utf-8" ?>
<RelativeLayout xmlns:android = "http://schemas.android.com/apk/res/android"
   xmlns:tools = "http://schemas.android.com/tools"
   android:layout_width = "match_parent"
   android:layout_height = "match_parent"
   android:padding = "16dp"
   tools:context = ".MainActivity" >
   <Button
      android:onClick= "createNotification"
      android:text= "create notification"
      android:layout_centerInParent= "true"
      android:layout_width= "match_parent"
      android:layout_height= "wrap_content" />
</RelativeLayout>
Step 3 − Add the following code to src/MainActivity.
package app.tutorialspoint.com.notifyme ;
import android.app.NotificationChannel ;
import android.app.NotificationManager ;
import android.app.PendingIntent ;
import android.content.Intent ;
import android.os.Bundle ;
import android.support.v4.app.NotificationCompat ;
import android.support.v7.app.AppCompatActivity ;
import android.view.View ;
public class MainActivity extends AppCompatActivity {
   public static final String NOTIFICATION_CHANNEL_ID = "10001" ;
   private final static String default_notification_channel_id = "default" ;
   @Override
   protected void onCreate (Bundle savedInstanceState) {
      super .onCreate(savedInstanceState) ;
      setContentView(R.layout. activity_main ) ;
   }
   public void createNotification (View view) {
      int NOTIFICATION_ID = ( int ) System. currentTimeMillis () ;
      PendingIntent pendingIntent = PendingIntent. getActivity ( this, 0 , new Intent() , 0 ) ;
      Intent buttonIntent = new Intent( this, NotificationBroadcastReceiver. class ) ;
      buttonIntent.putExtra( "notificationId" , NOTIFICATION_ID) ;
      PendingIntent btPendingIntent = PendingIntent. getBroadcast ( this, 0 , buttonIntent , 0 ) ;
      NotificationManager mNotificationManager = (NotificationManager) getSystemService( NOTIFICATION_SERVICE ) ;
      NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(getApplicationContext() , default_notification_channel_id ) ;
      mBuilder.setContentTitle( "My Notification" ) ;
      mBuilder.setContentIntent(pendingIntent) ;
      mBuilder.addAction(R.drawable. ic_launcher_foreground , "Cancel" , btPendingIntent) ;
      mBuilder.setContentText( "Notification Listener Service Example" ) ;
      mBuilder.setSmallIcon(R.drawable. ic_launcher_foreground ) ;
      mBuilder.setAutoCancel( true ) ;
      mBuilder.setDeleteIntent(getDeleteIntent()) ;
      if (android.os.Build.VERSION. SDK_INT >= android.os.Build.VERSION_CODES. O ) {
         int importance = NotificationManager. IMPORTANCE_HIGH ;
         NotificationChannel notificationChannel = new NotificationChannel( NOTIFICATION_CHANNEL_ID , "NOTIFICATION_CHANNEL_NAME" , importance) ;
         mBuilder.setChannelId( NOTIFICATION_CHANNEL_ID ) ;
         assert mNotificationManager != null;
         mNotificationManager.createNotificationChannel(notificationChannel) ;
      }
      assert mNotificationManager != null;
      mNotificationManager.notify(NOTIFICATION_ID , mBuilder.build()) ;
   }
   protected PendingIntent getDeleteIntent () {
      Intent intent = new Intent(MainActivity. this,
      NotificationBroadcastReceiver. class ) ;
      intent.setAction( "notification_cancelled" ) ;
      return PendingIntent. getBroadcast (MainActivity. this, 0 , intent , PendingIntent. FLAG_CANCEL_CURRENT ) ;
   }
}
Step 4 − Add the following code to src/NotificationBroadcastReceiver
package app.tutorialspoint.com.notifyme ;
import android.app.NotificationManager ;
import android.content.BroadcastReceiver ;
import android.content.Context ;
import android.content.Intent ;
public class NotificationBroadcastReceiver extends BroadcastReceiver {
   @Override
   public void onReceive (Context context , Intent intent) {
      int notificationId = intent.getIntExtra( "notificationId" , 0 ) ;
      // if you want cancel notification
      NotificationManager manager = (NotificationManager) context.getSystemService(Context. NOTIFICATION_SERVICE ) ;
      manager.cancel(notificationId) ;
   }
}
Step 5 − Add the following code to AndroidManifest.xml
<? xml version = "1.0" encoding = "utf-8" ?>
<manifest xmlns: android = "http://schemas.android.com/apk/res/android"
   package = "app.tutorialspoint.com.notifyme" >
   <uses-permission android :name = "android.permission.VIBRATE" />
   <uses-permission android :name = "android.permission.RECEIVE_BOOT_COMPLETED" />
   <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" >
      <receiver
         android :name = ".NotificationBroadcastReceiver"
         android :enabled = "true"
         android :exported = "true" >
      </receiver>
      <activity android :name = ".MainActivity" >
         <intent-filter>
            <action android :name = "android.intent.action.MAIN" />
            <category android :name = "android.intent.category.LAUNCHER" />
         </intent-filter>
      </activity>
   </application>
</manifest>
Let's try to run your application. I assume you have connected your actual Android Mobile device with your computer. To run the app from android studio, open one of your project's activity files and click Run  icon from the toolbar. Select your mobile device as an option and then check your mobile device which will display your default screen
Click  here  to download the project code