Android Notification Not Showing On API 26

Question

I recently updated my app to API 26, and notifications are no longer working, without even changing the code.

val notification = NotificationCompat.Builder(this)
                .setSmallIcon(R.drawable.ic_notification)
                .setContentTitle("Title")
                .setContentText("Text")
                .build()
(getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager).notify(1, notification)

Why isn't it working? Was there some change to the API that I'm not aware of?

Answer 1

Here i post some quick solution

public void notification(String title, String message, Context context) { 
    NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

    int notificationId = createID();
    String channelId = "channel-id";
    String channelName = "Channel Name";
    int importance = NotificationManager.IMPORTANCE_HIGH;

    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
        NotificationChannel mChannel = new NotificationChannel(
                channelId, channelName, importance);
        notificationManager.createNotificationChannel(mChannel);
    }

    NotificationCompat.Builder mBuilder = new NotificationCompat.Builder(context, channelId)
            .setSmallIcon(R.drawable.app_logo)//R.mipmap.ic_launcher
            .setContentTitle(title)
            .setContentText(message)
            .setVibrate(new long[]{100, 250})
            .setLights(Color.YELLOW, 500, 5000)
            .setAutoCancel(true)
            .setColor(ContextCompat.getColor(context, R.color.colorPrimary));

    TaskStackBuilder stackBuilder = TaskStackBuilder.create(context);
    stackBuilder.addNextIntent(new Intent(context, MainAcivity.class));
    PendingIntent resultPendingIntent = stackBuilder.getPendingIntent(0,PendingIntent.FLAG_UPDATE_CURRENT);
    mBuilder.setContentIntent(resultPendingIntent);

    notificationManager.notify(notificationId, mBuilder.build());
}

public int createID() {
    Date now = new Date();
    int id = Integer.parseInt(new SimpleDateFormat("ddHHmmss", Locale.FRENCH).format(now));
    return id;
}

Answer 2

From the documentation:

Android O introduces notification channels to provide a unified system to help users manage notifications. When you target Android O, you must implement one or more notification channels to display notifications to your users. If you don't target Android O, your apps behave the same as they do on Android 7.0 when running on Android O devices.

_{(emphasis added)}

You do not seem to be associating this Notification with a channel.