if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.LOLLIPOP) {
          Intent intent = new Intent();
          intent.setAction("android.settings.APP_NOTIFICATION_SETTINGS");
          intent.putExtra("app_package", getActivity().getPackageName());
          intent.putExtra("app_uid", getActivity().getApplicationInfo().uid);
          startActivity(intent);
        } else if (android.os.Build.VERSION.SDK_INT == Build.VERSION_CODES.KITKAT) {
          Intent intent = new Intent();
          intent.setAction(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
          intent.addCategory(Intent.CATEGORY_DEFAULT);
          intent.setData(Uri.parse("package:" + getActivity().getPackageName()));
          startActivity(intent);
        }

 Intent localIntent = new Intent();
        localIntent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        if (Build.VERSION.SDK_INT >= 9) {
          localIntent.setAction("android.settings.APPLICATION_DETAILS_SETTINGS");
          localIntent.setData(Uri.fromParts("package", getActivity().getPackageName(), null));
        } else if (Build.VERSION.SDK_INT <= 8) {
          localIntent.setAction(Intent.ACTION_VIEW);
          localIntent.setClassName("com.android.settings", "com.android.settings.InstalledAppDetails");
          localIntent.putExtra("com.android.settings.ApplicationPkgName", getActivity().getPackageName());
        }
        startActivity(localIntent);

NotificationManagerCompat manager = NotificationManagerCompat.from(App.getInstance().getContext());
boolean isOpened = manager.areNotificationsEnabled();