How to create a notification with NotificationCompat.Builder?

Working example:

    Intent intent = new Intent(ctx, HomeActivity.class);
    PendingIntent contentIntent = PendingIntent.getActivity(ctx, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);

    NotificationCompat.Builder b = new NotificationCompat.Builder(ctx);

    b.setAutoCancel(true)
     .setDefaults(Notification.DEFAULT_ALL)
     .setWhen(System.currentTimeMillis())         
     .setSmallIcon(R.drawable.ic_launcher)
     .setTicker("Hearty365")            
     .setContentTitle("Default notification")
     .setContentText("Lorem ipsum dolor sit amet, consectetur adipiscing elit.")
     .setDefaults(Notification.DEFAULT_LIGHTS| Notification.DEFAULT_SOUND)
     .setContentIntent(contentIntent)
     .setContentInfo("Info");


    NotificationManager notificationManager = (NotificationManager) ctx.getSystemService(Context.NOTIFICATION_SERVICE);
    notificationManager.notify(1, b.build());

The NotificationCompat.Builder is the most easy way to create Notifications on all Android versions. You can even use features that are available with Android 4.1. If your app runs on devices with Android >=4.1 the new features will be used, if run on Android <4.1 the notification will be an simple old notification.

To create a simple Notification just do (see Android API Guide on Notifications):

NotificationCompat.Builder mBuilder =
    new NotificationCompat.Builder(this)
    .setSmallIcon(R.drawable.notification_icon)
    .setContentTitle("My notification")
    .setContentText("Hello World!")
    .setContentIntent(pendingIntent); //Required on Gingerbread and below

You have to set at least smallIcon, contentTitle and contentText. If you miss one the Notification will not show.

Beware: On Gingerbread and below you have to set the content intent, otherwise a IllegalArgumentException will be thrown.

To create an intent that does nothing, use:

final Intent emptyIntent = new Intent();
PendingIntent pendingIntent = PendingIntent.getActivity(ctx, NOT_USED, emptyIntent, PendingIntent.FLAG_UPDATE_CURRENT);

You can add sound through the builder, i.e. a sound from the RingtoneManager:

mBuilder.setSound(RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION))

The Notification is added to the bar through the NotificationManager:

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

Show Notificaton in android 8.0

@TargetApi(Build.VERSION_CODES.O)
@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)

  public void show_Notification(){

    Intent intent=new Intent(getApplicationContext(),MainActivity.class);
    String CHANNEL_ID="MYCHANNEL";
    NotificationChannel notificationChannel=new NotificationChannel(CHANNEL_ID,"name",NotificationManager.IMPORTANCE_LOW);
    PendingIntent pendingIntent=PendingIntent.getActivity(getApplicationContext(),1,intent,0);
    Notification notification=new Notification.Builder(getApplicationContext(),CHANNEL_ID)
            .setContentText("Heading")
            .setContentTitle("subheading")
            .setContentIntent(pendingIntent)
            .addAction(android.R.drawable.sym_action_chat,"Title",pendingIntent)
            .setChannelId(CHANNEL_ID)
            .setSmallIcon(android.R.drawable.sym_action_chat)
            .build();

    NotificationManager notificationManager=(NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        notificationManager.createNotificationChannel(notificationChannel);
    notificationManager.notify(1,notification);


}