I get Toast on Android 8.1 API 27:
Developer warning for package "my_package_name"
Failed to post notification on ...
Logcat includes next strings:
Notification: Use of stream types is deprecated for operations other than volume control
W/Notification: See the documentation of setSound() for what to use instead with android.media.AudioAttributes to qualify your playback use case
E/NotificationService: No Channel found for pkg=my_package_name
The full information in the Toast and in Logcat can help in the localization this problem.
If you get this error should be paid attention to 2 items and them order:
NotificationChannel mChannel = new NotificationChannel(id, name, importance);
builder = new NotificationCompat.Builder(context, id);
Also NotificationManager notifManager and NotificationChannel mChannel are created only once.
There are required setters for Notification:
See example:
private NotificationManager notifManager;
public void createNotification(String aMessage, Context context) {
final int NOTIFY_ID = 0; // ID of notification
String id = context.getString(R.string.default_notification_channel_id); // default_channel_id
String title = context.getString(R.string.default_notification_channel_title); // Default Channel
Intent intent;
PendingIntent pendingIntent;
NotificationCompat.Builder builder;
if (notifManager == null) {
notifManager = (NotificationManager)context.getSystemService(Context.NOTIFICATION_SERVICE);
}
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
int importance = NotificationManager.IMPORTANCE_HIGH;
NotificationChannel mChannel = notifManager.getNotificationChannel(id);
if (mChannel == null) {
mChannel = new NotificationChannel(id, title, importance);
mChannel.enableVibration(true);
mChannel.setVibrationPattern(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400});
notifManager.createNotificationChannel(mChannel);
}
builder = new NotificationCompat.Builder(context, id);
intent = new Intent(context, MainActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
pendingIntent = PendingIntent.getActivity(context, 0, intent, 0);
builder.setContentTitle(aMessage) // required
.setSmallIcon(android.R.drawable.ic_popup_reminder) // required
.setContentText(context.getString(R.string.app_name)) // required
.setDefaults(Notification.DEFAULT_ALL)
.setAutoCancel(true)
.setContentIntent(pendingIntent)
.setTicker(aMessage)
.setVibrate(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400});
}
else {
builder = new NotificationCompat.Builder(context, id);
intent = new Intent(context, MainActivity.class);
intent.setFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_SINGLE_TOP);
pendingIntent = PendingIntent.getActivity(context, 0, intent, 0);
builder.setContentTitle(aMessage) // required
.setSmallIcon(android.R.drawable.ic_popup_reminder) // required
.setContentText(context.getString(R.string.app_name)) // required
.setDefaults(Notification.DEFAULT_ALL)
.setAutoCancel(true)
.setContentIntent(pendingIntent)
.setTicker(aMessage)
.setVibrate(new long[]{100, 200, 300, 400, 500, 400, 300, 200, 400})
.setPriority(Notification.PRIORITY_HIGH);
}
Notification notification = builder.build();
notifManager.notify(NOTIFY_ID, notification);
}