Send Notification based on time Android

Question

I am new to Android development, and I need to send a notification based on 2 cases:

1. On "showNotification" Button Click using "showNotification" Method
2. After a period of time (5 seconds after "alertNotification" button clicked in my example) using "alertNotification" method as below:

The first case has worked perfect. But, I am having a problem with the Second case.

I followed the same way explained on https://youtu.be/gm5n_hRIR-c

Here are my Code:

1. MainActivity.java

   public class MainActivity extends Activity {
       // Send Notification on button click
       Button showNotification;
       // Send Notification 5 second after on button click
       Button alertNotification;
       NotificationManager notificationManager;
       boolean isNotificActive = false;
   
       int notifID = 33;
   
       public static final int NOTIFICATION_ID = 1;
   
       public void onCreate(Bundle savedInstanceState) {
           super.onCreate(savedInstanceState);
           setContentView(R.layout.sample_layout);
   
           showNotification = (Button) findViewById(R.id.showNotification);
           alertNotification = (Button) findViewById(R.id.alerNotification);
       }
   
       public void showNotification(View view) {
           NotificationCompat.Builder notificationBuilder = new NotificationCompat.Builder(this)
                   .setContentTitle("Notification")
                   .setContentText("New Notification")
                   .setTicker("Alert New Notification")
                   .setSmallIcon(R.drawable.ic_stat_notification);
   
           Intent moreInfoIntent = new Intent(this, MoreNotification.class);
           TaskStackBuilder stackBuilder = null;
           if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.JELLY_BEAN) {
               stackBuilder = TaskStackBuilder.create(this);
   
               stackBuilder.addParentStack(MoreNotification.class);
               stackBuilder.addNextIntent(moreInfoIntent);
   
               PendingIntent pendingIntent = stackBuilder.getPendingIntent(0, PendingIntent.    FLAG_UPDATE_CURRENT);
   
               notificationBuilder.setContentIntent(pendingIntent);
   
               notificationManager = (NotificationManager) getSystemService(Context.    NOTIFICATION_SERVICE);
   
               notificationManager.notify(notifID, notificationBuilder.build());
   
               isNotificActive = true;
           }
       }
   
       public void alertNotification(View view) {
           Long alertTime = new GregorianCalendar().getTimeInMillis()+5*1000;
           Intent alertIntent = new Intent(this, AlertReceiver.class);
   
           AlarmManager alarmManager = (AlarmManager) getSystemService(Context.ALARM_SERVICE);
   
           alarmManager.set(AlarmManager.RTC_WAKEUP, alertTime, PendingIntent.getBroadcast(
                   this, 1, alertIntent, PendingIntent.FLAG_UPDATE_CURRENT));
   
           Log.e("alarmManager", "alarmManager");
       }
   }
   

2. AlertReceiver.java

   public class AlertReceiver extends BroadcastReceiver {
       @Override
       public void onReceive(Context context, Intent intent) {
           Log.e("onReceive", "onReceive");
           createNotification(context, "Times UP", "5 Seconds Has Passed", "Alert");
       }
   
       public void createNotification(Context context, String msg, String msgText, String msgAlert) {
           PendingIntent notificationIntent = PendingIntent.getActivity(context, 0,
                   new Intent(context, MainActivity.class), 0);
   
           NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(context)
                   .setSmallIcon(R.drawable.ic_stat_notification)
                   .setContentTitle(msg)
                   .setTicker(msgAlert)
                   .setContentText(msgText);
   
           mBuilder.setContentIntent(notificationIntent);
           mBuilder.setDefaults(NotificationCompat.DEFAULT_SOUND);
           mBuilder.setAutoCancel(true);
   
           NotificationManager mNotificationManager = (NotificationManager) context.getSystemService(      Context.NOTIFICATION_SERVICE);
   
           mNotificationManager.notify(1, mBuilder.build()); 
       }
   }
   

3. AndroidManifest.xml

   <!-- Min/target SDK versions (<uses-sdk>) managed by build.gradle -->
   
   <uses-permission android:name="com.android.alarm.permission.SET_ALARM" />
   
   <application
       android:allowBackup="true"
       android:icon="@drawable/ic_launcher"
       android:label="@string/app_name"
       android:theme="@style/AppTheme">
       <activity
           android:name=".MainActivity"
           android:label="@string/app_name">
           <intent-filter>
               <action android:name="android.intent.action.MAIN" />
   
               <category android:name="android.intent.category.LAUNCHER" />
           </intent-filter>
       </activity>
   
       <activity
           android:name=".MoreNotification"
           android:label="More Notification"
           android:parentActivityName=".MainActivity">
           <meta-data
               android:name="android.support.PARENT_ACTIVITY"
               android:value=".MainActivity"/>
   
   
       </activity>
   </application>
   

Answer 1

AlertReceiver must be registered in AndroidManifest.xml.

<application
    android:allowBackup="true"
    android:icon="@drawable/ic_launcher"
    android:label="@string/app_name"
    android:theme="@style/AppTheme">

    <!-- Your stuff here. -->

    <receiver android:name=".AlertReceiver"/>

</application>