How to actually control a drone using VirtualSticks

Question

I'm struggling with sending commands to drone using DJI SDK. I'm using Phantom 4 V2.0 and DJI SDK version 4.15. There's a tutorial on how to use VirtualSticks to command the drone but only applicable to simulator. I tried using the same code to fly an actual drone but to no success. If I start the motors via provided method they will stop immediately, probably because of the commands my app is sending to the drone while sticks are idle. This is the code:

screenJoystickLeft.setJoystickListener((joystick, pX, pY) -> {
        if (Math.abs(pX) < 0.02) {
            pX = 0;
        }

        if (Math.abs(pY) < 0.02) {
            pY = 0;
        }
        float pitchJoyControlMaxSpeed = 10;
        float rollJoyControlMaxSpeed = 10;

        if (horizontalCoordinateFlag) {
            if (rollPitchControlModeFlag) {
                pitch = (float) (pitchJoyControlMaxSpeed * pX);

                roll = (float) (rollJoyControlMaxSpeed * pY);
            } else {
                pitch = -(float) (pitchJoyControlMaxSpeed * pY);

                roll = (float) (rollJoyControlMaxSpeed * pX);
            }
        }

        if (null == sendVirtualStickDataTimer) {
            sendVirtualStickDataTask = new SendVirtualStickDataTask();
            sendVirtualStickDataTimer = new Timer();
            sendVirtualStickDataTimer.schedule(sendVirtualStickDataTask, 100, 200);
        }
    });

    screenJoystickRight.setJoystickListener((joystick, pX, pY) -> {
        if (Math.abs(pX) < 0.02) {
            pX = 0;
        }

        if (Math.abs(pY) < 0.02) {
            pY = 0;
        }
        float verticalJoyControlMaxSpeed = 2;
        float yawJoyControlMaxSpeed = 3;

        yaw = yawJoyControlMaxSpeed * pX;
        throttle = (verticalJoyControlMaxSpeed * pY) < 1 ? 1 : (verticalJoyControlMaxSpeed * pY);

        if (null == sendVirtualStickDataTimer) {
            sendVirtualStickDataTask = new SendVirtualStickDataTask();
            sendVirtualStickDataTimer = new Timer();
            sendVirtualStickDataTimer.schedule(sendVirtualStickDataTask, 0, 200);
        }

        Log.d(TAG, "Right vertical: " + pY);
    });

Any ideas on how to modify my code to fly an actual drone successfully? Has anyone done it some other way maybe? This code is taken from DJI Demo GitHub.