Display a view using windowmanager on lock screen

Question

I have a float icon that stays on top of all activities, but when the device get locked it disappear until the device get unlocked.

Another meaning, I want to display a

Answer 1

Don't add view in the OnCreate itself. Instead make a Broadcast receiver and pass the intent to it. This will show your icon only when the screen is locked. And it will go away when the screen is unlocked. Following is the code snippet. Don't forget to list your service in the manifest.

public class FloatingIconService extends Service {

private BroadcastReceiver mReceiver;
private boolean isShowing = false;
private WindowManager windowManager;
public ImageView icon;
private WindowManager.LayoutParams params;

@Nullable
@Override
public IBinder onBind(Intent intent) {
    return null;
}

@Override
public int onStartCommand(Intent intent, int flags, int startId) {

    Log.i("onStart", "FloatingIconService");

    return super.onStartCommand(intent,flags,startId);
}

@Override
public void onCreate() {
    super.onCreate();

    windowManager = (WindowManager) getSystemService(WINDOW_SERVICE);

    //add icon and its properties
    icon = new ImageView(this);
    icon.setImageResource(R.drawable.ic_action_name);
    icon.setClickable(true);
    icon.setPadding(10, 10, 10, 10);
    icon.setOnLongClickListener(new View.OnLongClickListener() {
        @Override
        public boolean onLongClick(View view) {

            Log.i("onStart", "FloatingIconService when long press on icon");
            ((Vibrator) getApplicationContext().getSystemService(Context.VIBRATOR_SERVICE)).vibrate(1000);

            Intent i = new Intent(getApplicationContext(), Dashboard.class);
            i.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);

            startActivity(i);
            return true;
        }
    });

    //set parameters for the icon
    params = new WindowManager.LayoutParams(
            WindowManager.LayoutParams.WRAP_CONTENT,
            WindowManager.LayoutParams.WRAP_CONTENT,
            WindowManager.LayoutParams.TYPE_SYSTEM_ERROR,
            WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
                    | WindowManager.LayoutParams.FLAG_NOT_TOUCH_MODAL
                    | WindowManager.LayoutParams.FLAG_SHOW_WHEN_LOCKED
                    | WindowManager.LayoutParams.FLAG_WATCH_OUTSIDE_TOUCH,
            PixelFormat.TRANSLUCENT);
    params.gravity = Gravity.BOTTOM;
    params.x=0;
    params.y=0;

    //Register receiver for determining screen off and if user is present
    mReceiver = new FloatingIconReceiver();
    IntentFilter filter = new IntentFilter(Intent.ACTION_SCREEN_OFF);
    filter.addAction(Intent.ACTION_USER_PRESENT);

    registerReceiver(mReceiver, filter);
}

private class FloatingIconReceiver extends BroadcastReceiver {
    @Override
    public void onReceive(Context context, Intent intent) {
        if (intent.getAction().equals(Intent.ACTION_SCREEN_OFF)) {
            //if screen is turn off show the icon
            if (!isShowing) {
                windowManager.addView(icon, params);
                isShowing = true;
            }
        } else if (intent.getAction().equals(Intent.ACTION_USER_PRESENT)) {
            //Handle resuming events if user is present/screen is unlocked remove the icon immediately
            if (isShowing) {
                windowManager.removeViewImmediate(icon);
                isShowing = false;
            }
        }
    }
}

@Override
public void onDestroy() {
    super.onDestroy();

    if (mReceiver != null) {
        unregisterReceiver(mReceiver);
    }

    //remove view if it is showing and the service is destroy
    if (isShowing) {
        windowManager.removeViewImmediate(icon);
        isShowing = false;
    }
    super.onDestroy();
}

}

Only if someone could help me make this icon float. Like we can do it in activities using FAB.