Gadgetbridge/app/src/main/java/nodomain/freeyourgadget/gadgetbridge/GB.java

package nodomain.freeyourgadget.gadgetbridge;

import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;
import android.content.ComponentName;
import android.content.Context;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.support.v4.app.NotificationCompat;

public class GB {
    public static final int NOTIFICATION_ID = 1;

    public static Notification createNotification(String text, Context context) {
        Intent notificationIntent = new Intent(context, ControlCenter.class);
        notificationIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK
                | Intent.FLAG_ACTIVITY_CLEAR_TASK);
        PendingIntent pendingIntent = PendingIntent.getActivity(context, 0,
                notificationIntent, 0);

        return new NotificationCompat.Builder(context)
                .setContentTitle("Gadgetbridge")
                .setTicker(text)
                .setContentText(text)
                .setSmallIcon(R.drawable.ic_notification)
                .setContentIntent(pendingIntent)
                .setOngoing(true).build();
    }

    public static void updateNotification(String text, Context context) {
        Notification notification = createNotification(text, context);

        NotificationManager nm = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);
        nm.notify(NOTIFICATION_ID, notification);
    }

    public static void setReceiversEnableState(boolean enable, Context context) {
        final Class[] receiverClasses = {
                PhoneCallReceiver.class,
                SMSReceiver.class,
                K9Receiver.class,
                MusicPlaybackReceiver.class,
                //NotificationListener.class, // disabling this leads to loss of permission to read notifications
        };

        int newState;

        if (enable) {
            newState = PackageManager.COMPONENT_ENABLED_STATE_ENABLED;
        } else {
            newState = PackageManager.COMPONENT_ENABLED_STATE_DISABLED;
        }

        PackageManager pm = context.getPackageManager();

        for (Class receiverClass : receiverClasses) {
            ComponentName compName = new ComponentName(context, receiverClass);

            pm.setComponentEnabledSetting(compName, newState, PackageManager.DONT_KILL_APP);
        }
    }
}