No LED light for notification Android

Question

no matter what I tried but there is no notification light. I'm running Android 26 Oreo. My phone only displays blink light for messages and missed calls.

String CHANNEL_ID = "my_channel_01";
NotificationManager nm = (NotificationManager) getSystemService(NOTIFICATION_SERVICE);
CharSequence name = "Name"; // The user-visible name of the channel.
int importance = NotificationManager.IMPORTANCE_HIGH;
NotificationChannel mChannel = null;
if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
    mChannel = new NotificationChannel("my_channel_01", name, importance);
    mChannel.enableLights(true);
    mChannel.setLightColor(Color.GREEN);
    mChannel.shouldShowLights();
    nm.createNotificationChannel(mChannel);
}

Notification notif = new Notification.Builder(MainActivity.this)
        .setSmallIcon(R.mipmap.ic_launcher_2)
        .setContentTitle("Blhas")
        .setContentText("Subject")
        .setSubText("Subtext")
        .setColor(Color.RED)
        .setLights(255, 0, 0)
        .setContentIntent(pIntent)
        .setStyle(new Notification.BigTextStyle().bigText("..."))
        .setChannelId(CHANNEL_ID)
        .setPriority(Notification.PRIORITY_HIGH)
        .build();
nm.notify(LED_NOTIFICATION_ID, notif);

Is there anyway to control the LED light?

Answer 1

I had the same problem,I found out that once we give a channel NotificationManager.IMPORTANCE_LOW for a particular channel ID,the channel remains with that importance,even if we change the importance later,even reboot would not change that for that particular channel ID.When we give the importance to NotificationManager.IMPORTANCE_LOW ,for a particular channel ID,we don't get the notification led light,and it stays that way,so the solutions I found were to uninstall the app and reinstall it again but this time giving the importance to NotificationManager.IMPORTANCE_DEFAULT or higher,or we can change the channel ID completely. And not only importance stays that way,also any call to the other methods on the channel stays the same for a particular channel ID.

                    mChannel.enableLights(true);
                    mChannel.setLightColor(Color.RED);
                    mChannel.setSound(Uri.parse("android.resource://" + getPackageName() + "/" + R.raw.silent),null);