Heads up notification not showing in android O and higher

问题

I literally have tried everything seriously every method and every snippet but still, I was not able to show heads-up notifications on Chinese brand devices.

so yesterday I thought why not try it again but after all again still I'm not able to show heads-up notification until I manually goto the app into the settings and give floating permission for the app.

Now most of you may say why not to navigate the user to the setting when he/she first opens up the app but nobody likes that even there are other apps (I'm not talking about white list app like WhatsApp) which have 10K downloads are able to show heads up notification

Here is my code, btw I have tried setting the sound, vibration, and light but still heads up are not showing, and yes I do uninstall my app after every build

    public void showNotification(View v){
        if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.O){
            NotificationChannel nc = new NotificationChannel("n","pop up notification", NotificationManager.IMPORTANCE_HIGH);
            nc.enableLights(true);
            nc.setLightColor(Color.BLUE);
            nc.enableVibration(true);
            nc.setLockscreenVisibility(Notification.VISIBILITY_PUBLIC);
            NotificationManager nm = getSystemService(NotificationManager.class);
            nm.createNotificationChannel(nc);
        }

        Notification.Builder notification = null;
        if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
            notification = new Notification.Builder(this,"n")
                    .setContentTitle("Pop up notification")
                    .setSmallIcon(R.drawable.ic_launcher_background);
        }else{
            notification = new Notification.Builder(this)
                    .setContentTitle("Pop up notification")
//                    .setPriority(Notification.PRIORITY_MAX)
                    .setSmallIcon(R.drawable.ic_launcher_background);
        }
        NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
        notificationManager.notify(1,notification.build());
    }

回答1:

I have two solutions. Try them out and see if any works.

1. Yours actually works Like this

    public void showNotification(){
   
    if(Build.VERSION.SDK_INT >= Build.VERSION_CODES.O){
        NotificationChannel nc = new NotificationChannel("n","pop up notification", NotificationManager.IMPORTANCE_HIGH);
        nc.enableLights(true);
        nc.setLightColor(Color.BLUE);
        nc.enableVibration(true);
        nc.setLockscreenVisibility(Notification.VISIBILITY_PUBLIC);
        NotificationManager nm = getSystemService(NotificationManager.class);
        nm.createNotificationChannel(nc);
    }
   
    Notification.Builder notification = null;
    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
        notification = new Notification.Builder(this,"n")
                .setContentTitle("Pop up notification")
                .setSmallIcon(R.drawable.alex);
    }else{
        notification = new Notification.Builder(this)
                .setContentTitle("Pop up notification")
                //.setPriority(Notification.PRIORITY_MAX)
                .setSmallIcon(R.drawable.alex);
    }
    NotificationManager notificationManager = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    notificationManager.notify(1,notification.build());
   

2. Mine notifyUser("Order Delivery", "Your order has arrived"):

    public void notifyUser(String title, String text){
    NotificationCompat.Builder builder = new NotificationCompat.Builder(this, "notify_001");
    Intent intent = new Intent(this, ActivityToOpenWhenNotificationIsTapped.class);
    intent.setAction("android.intent.action.MAIN");
    intent.addCategory("android.intent.category.LAUNCHER");
    intent.setFlags(Intent.FLAG_ACTIVITY_BROUGHT_TO_FRONT);
    intent.addFlags(Intent.FLAG_ACTIVITY_FORWARD_RESULT);
    PendingIntent activity = PendingIntent.getActivity(this, 0, intent, PendingIntent.FLAG_UPDATE_CURRENT);
    NotificationCompat.BigTextStyle bigTextStyle = new NotificationCompat.BigTextStyle();
    bigTextStyle.setBigContentTitle(title);
    bigTextStyle.bigText(text);
    bigTextStyle.setSummaryText("Big summary text. Comment if you want.");
    builder.setAutoCancel(true);
    builder.setContentIntent(activity);
    builder.setContentTitle(title);
    builder.setContentText(text);
    builder.setPriority(1);
    builder.setSmallIcon(R.drawable.alex);
    builder.setLargeIcon(BitmapFactory.decodeResource(this.getResources(), R.drawable.alex));
    builder.setStyle(bigTextStyle);
    builder.setAutoCancel(true);
    builder.setSound(Settings.System.DEFAULT_NOTIFICATION_URI);
    builder.setGroup("Pixels");
    Notification build = builder.build();
    build.flags |= 16;
    NotificationManager notificationManager = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
    if (Build.VERSION.SDK_INT >= 26) {
        String str3 = "Pixels_V1.0";
        notificationManager.createNotificationChannel(new NotificationChannel(str3, "Pixels Notification", NotificationManager.IMPORTANCE_DEFAULT));
        builder.setChannelId(str3);
    }
    int NOTIFICATION_ID =  new Random(System.currentTimeMillis()).nextInt(1000);
    notificationManager.notify(NOTIFICATION_ID, builder.build());
    }
   

来源：https://stackoverflow.com/questions/65263749/heads-up-notification-not-showing-in-android-o-and-higher