applyForce as long as display is pressed

Question

In my project I have my main character body. I want it to move down on the y-axis as long as the screen is pressed. I tried it with

public boolean touchUp(int screenX, int screenY, int pointer, int button) {
        jetski.applyForce(new Vector2(0,-1000), jetski.getWorldCenter(), true);
        return true;
    }

but that does it only once.

Answer 1

I assume there is a main loop in your project since it looks like you are developing a game. It is typically done using flag(-s) to represent the user input. Let's say we have a flag isTouched . So, when the user first touches the display, isTouched = true . Then when the user no longer touches the display, isTouched = false . Finally, in your main loop if (isTouched) applyForce(); . Android API or libgdx (judging from tags) should be able to provide listeners for both onTouch and onTouchRelease events. Mind you they may be called something different.

Answer 2

Try this:

boolean isTouched = false;

public boolean touchDown(int screenX, int screenY, int pointer, int button) {
        isTouched = true;
        return true;
}

public boolean touchUp(int screenX, int screenY, int pointer, int button) {
        isTouched = false;
        return true;
}

public void update(float delta) {
    // update other stuff

    if (isTouched) {
        jetski.applyForce(new Vector2(0,-1000), jetski.getWorldCenter(), true);
    }

    // update other stuff
}  

You might want to change -1000 to something lower, because it will add -1000 force every frame, and maybe add a limit. Also, judging by the force(-1000) I'm guessing you didn't scale the world, so the physics might not work as expected.