Using the Notification Manager in Android. This article describes how to use the Notification Manager in Android. It is based on Android Studio and Android 5.0.

1. Notification Manager

1.1. Notification Manager

Android allows to put notification into the titlebar of your application. The user can expand the notification bar and by selecting the notification the user can trigger another activity.

Because notifications can be very annoying, the user can disable notifications for each application. This can be done via the Settings application of the Android device. Select Apps in the Settings, select the app you are interested in and unset the Show notifications checkbox to prevent the app to show notifications.

Showing the Notification bar with the created notification

1.2. Setting up Notifications

Notifications in Android are represented by the Notification class. To create notifications you use the NotificationManager class which can be received from the Context, e.g. an activity or a service, via the getSystemService() method.

NotificationManager notificationManager = (NotificationManager)
    getSystemService(NOTIFICATION_SERVICE);

The Notification.Builder provides an builder interface to create an Notification object. You use a PendingIntent to specify the action which should be performed once the user select the notification.

The Notification.Builder allows you to add up to three buttons with definable actions to the notification.

// prepare intent which is triggered if the
// notification is selected

Intent intent = new Intent(this, NotificationReceiver.class);
// use System.currentTimeMillis() to have a unique ID for the pending intent
PendingIntent pIntent = PendingIntent.getActivity(this, (int) System.currentTimeMillis(), intent, 0);

// build notification
// the addAction re-use the same intent to keep the example short
Notification n  = new Notification.Builder(this)
                .setContentTitle("New mail from " + "test@gmail.com")
                .setContentText("Subject")
                .setSmallIcon(R.drawable.icon)
                .setContentIntent(pIntent)
                .setAutoCancel(true)
                .addAction(R.drawable.icon, "Call", pIntent)
                .addAction(R.drawable.icon, "More", pIntent)
                .addAction(R.drawable.icon, "And more", pIntent).build();


NotificationManager notificationManager =
    (NotificationManager) getSystemService(NOTIFICATION_SERVICE);

notificationManager.notify(0, n);
Showing the Notification bar with the created notification

Android 4.1 supports expandable notifications. In addition to normal notification view it is possible to define a big view which gets shown when notification is expanded. There are three styles to be used with the big view: big picture style, big text style, Inbox style. The following code demonstrates the usage of the BigTextStyle() which allows to use up to 256 dp.

String longText = "...";

Notification noti = new Notification.Builder(this).
.....
.setStyle(new Notification.BigTextStyle().bigText(longText))
Showing the Notification bar with the created notification

1.3. Canceling Notifications

The user can dismiss all notification or if you set your notification to auto-cancel it is also removed once the user selects it.

You can also call the cancel() for a specific notification ID on the NotificationManager. The cancelAll() method call removes all of the notifications you previously issued.

2. Example: NotificationManager

Create a new project called de.vogella.android.notificationmanager with the activity class called CreateNotificationActivity. This activity should use the main.xml layout file.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <Button
        android:id="@+id/button1"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:onClick="createNotification"
        android:text="Create Notification" >
    </Button>

</LinearLayout>

Create the following result.xml layout file.

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent" >

    <TextView
        android:id="@+id/textView1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="This is the result activity opened from the notification" >
    </TextView>

</LinearLayout>

Create a new activity called NotificationReceiverActivity with the following coding. Don’t forget to register the activity in the AndroidManfest.mf.

package de.vogella.android.notificationmanager;

import android.app.Activity;
import android.os.Bundle;

public class NotificationReceiverActivity extends Activity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.result);
    }
}

Change the CreateNotificationActivity class to the following coding.

package de.vogella.android.notificationmanager;

import android.app.Activity;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;

public class CreateNotificationActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
    }

    public void createNotification(View view) {
        // Prepare intent which is triggered if the
        // notification is selected
        Intent intent = new Intent(this, NotificationReceiverActivity.class);
        PendingIntent pIntent = PendingIntent.getActivity(this, (int) System.currentTimeMillis(), intent, 0);

        // Build notification
        // Actions are just fake
        Notification noti = new Notification.Builder(this)
                .setContentTitle("New mail from " + "test@gmail.com")
                .setContentText("Subject").setSmallIcon(R.drawable.icon)
                .setContentIntent(pIntent)
                .addAction(R.drawable.icon, "Call", pIntent)
                .addAction(R.drawable.icon, "More", pIntent)
                .addAction(R.drawable.icon, "And more", pIntent).build();
        NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
        // hide the notification after its selected
        noti.flags |= Notification.FLAG_AUTO_CANCEL;

        notificationManager.notify(0, noti);

    }
}

Run your application and press the button. A new notification is created. If you select it your second activity will be displayed.