Android抬头通知未显示在Android Lollipop上

Question

我正在使用此代码生成推送通知

public class createNotification {
private Context context;
String CHANNEL_ID = "my_channel_01";
int NOTIFICATION_ID = 1;

public createNotification(Context context, String title, String body) {
    this.context=context;

    NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

    if (android.os.Build.VERSION.SDK_INT >= android.os.Build.VERSION_CODES.O) {
        String CHANNEL_ID = "my_channel_01";
        CharSequence name = "my_channel";
        String Description = "This is my channel";
        int importance = NotificationManager.IMPORTANCE_HIGH;
        NotificationChannel mChannel = new NotificationChannel(CHANNEL_ID, name, importance);
        mChannel.setDescription(Description);
        mChannel.enableLights(true);
        notificationManager.createNotificationChannel(mChannel);
    }

    NotificationCompat.Builder builder = new NotificationCompat.Builder(context, CHANNEL_ID)
            .setVibrate(new long[]{500, 500})
            .setSmallIcon(R.drawable.my_app_icon)
            .setContentTitle(title)
            .setPriority(Notification.PRIORITY_MAX)
            .setContentText(body);

    notificationManager.notify(NOTIFICATION_ID, builder.build());
    NOTIFICATION_ID++;
  }
}

抬头通知显示在Android 7真实设备上，但不显示在Android 5上，我仅得到图标和振动。我在this question中尝试了解决方案，但对我没有用。如何编辑此代码以在Android 5上显示Hedas-Up通知？