[android] How to create a notification with NotificationCompat.Builder?

Notification in depth

CODE

Intent intent = new Intent(this, SecondActivity.class);
PendingIntent pendingIntent = PendingIntent.getActivity(this,0,intent,0);

NotificationCompat.Builder mBuilder =
                new NotificationCompat.Builder(context)
                        .setSmallIcon(R.drawable.your_notification_icon)
                        .setContentTitle("Notification Title")
                        .setContentText("Notification ")
                        .setContentIntent(pendingIntent );

NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
notificationManager.notify(0, mBuilder.build());

Depth knowledge

Notification can be build using Notification. Builder or NotificationCompat.Builder classes.
But if you want backward compatibility you should use NotificationCompat.Builder class as it is part of v4 Support library as it takes care of heavy lifting for providing consistent look and functionalities of Notification for API 4 and above.

Core Notification Properties

A notification has 4 core properties (3 Basic display properties + 1 click action property)

• Small icon
• Title
• Text
• Button click event (Click event when you tap the notification )

Button click event is made optional on Android 3.0 and above. It means that you can build your notification using only display properties if your minSdk targets Android 3.0 or above. But if you want your notification to run on older devices than Android 3.0 then you must provide Click event otherwise you will see IllegalArgumentException.

Notification Display

Notification are displayed by calling notify() method of NotificationManger class

notify() parameters

There are two variants available for notify method

notify(String tag, int id, Notification notification)

or

notify(int id, Notification notification)

notify method takes an integer id to uniquely identify your notification. However, you can also provide an optional String tag for further identification of your notification in case of conflict.

This type of conflict is rare but say, you have created some library and other developers are using your library. Now they create their own notification and somehow your notification and other dev's notification id is same then you will face conflict.

Notification after API 11 (More control)

API 11 provides additional control on Notification behavior

• Notification Dismissal
  By default, if a user taps on notification then it performs the assigned click event but it does not clear away the notification. If you want your notification to get cleared when then you should add this

  mBuilder.setAutoClear(true);

• Prevent user from dismissing notification
  A user may also dismiss the notification by swiping it. You can disable this default behavior by adding this while building your notification

  mBuilder.setOngoing(true);

• Positioning of notification
  You can set the relative priority to your notification by

  mBuilder.setOngoing(int pri);

If your app runs on lower API than 11 then your notification will work without above mentioned additional features. This is the advantage to choosing NotificationCompat.Builder over Notification.Builder

Notification after API 16 (More informative)

With the introduction of API 16, notifications were given so many new features
Notification can be so much more informative.
You can add a bigPicture to your logo. Say you get a message from a person now with the mBuilder.setLargeIcon(Bitmap bitmap) you can show that person's photo. So in the statusbar you will see the icon when you scroll you will see the person photo in place of the icon. There are other features too

• Add a counter in the notification
• Ticker message when you see the notification for the first time
• Expandable notification
• Multiline notification and so on