Sprite movement only works the first time, can't figure out why [closed]

Question

In my libGDX game I have finally managed to get the sprite to move the way I want him to but for some reason my desired outcome only works the first time I run the code. If I try to run it again, he immediately flies off the screen. If I then comment out one of the brackets, save and then put it back in and run a test, he moves as I want him to (but only the first time). Am I missing something?

EDIT: Ok I changed the code and now I have a new problem, he moves but not smoothly like he does when I move him with the keyboard. now he sort of teleports forwards or backwards about 5pixels every time the screen is clicked (or touched).

Partial Player class:

public class Player extends Entity implements InputProcessor{

OrthographicCamera camera;
Rectangle rectangle;
Vector3 touchPos;

public Player(Vector2 pos, Vector2 direction) {
    super(TextureManager.PLAYER, pos, direction);
    rectangle = new Rectangle(); //for hitbox
    }

@Override
public void update() {

    camera = new OrthographicCamera(240, 400);
    camera.position.set(240 / 2, 400 / 2, 0);
    rectangle.set(pos.x, pos.y + 40, 32, 22); //hitbox
    touchPos = new Vector3();

    pos.add(direction);{

        Gdx.input.setInputProcessor(this);


    //the keyboard inputs below work exactly how I want them to     
    if(Gdx.input.isKeyPressed(Keys.A)) // left
        setDirection(-300, 0);
    else if(Gdx.input.isKeyPressed(Keys.D)) // right
        setDirection(300, 0);
    else
        setDirection(0, 0);         
    }

    // make sure player stays inside stage
    if (pos.x < 0) pos.x = 0;
    else if (pos.x > 240 - 32) pos.x = 240 - 32;

}

public void moveLeft() {
    setDirection(-300, 0);
}

public void moveRight() {
    setDirection(300, 0);
}

public void Still() {
    setDirection(0, 0);
}


@Override
public boolean touchDown(int screenX, int screenY, int pointer, int button) {
    // TODO Auto-generated method stub
    if (screenX < ManicMeltdowns.WIDTH / 2 && screenY > ManicMeltdowns.HEIGHT / 2){
        moveLeft();
    }

    if (screenX > ManicMeltdowns.WIDTH / 2 && screenY > ManicMeltdowns.HEIGHT / 2){
        moveRight();
    }
    return true;
}

@Override
public boolean touchUp(int screenX, int screenY, int pointer, int button) {
    // TODO Auto-generated method stub
    if (screenX < ManicMeltdowns.WIDTH / 2 && screenY > ManicMeltdowns.HEIGHT / 2){
        Still();
    }

    if (screenX > ManicMeltdowns.WIDTH / 2 && screenY > ManicMeltdowns.HEIGHT / 2){
        Still();
    }
    return true;
}

Thanks

Answer 1

The issue is the else condition after you check the A and D keys, since if no key is pressed it will reset the direction to 0, 0 every time the update() method is called. Instead of calling moveLeft() and moveRight() in the touchDown and touchUp you should keep track of each pointer passed by the touchDown and touchUp methods and check whether the pointers are in the zones for a left or right movement in the update() method.

For example, create a class Pointer:

public class Pointer {
    public int x = 0, y = 0;
    public boolean down = false;
}

Then, create an array of pointers, touches[], in either the game class or the Player class to keep track of the touches. The length of touches[] should be however many touches you plan on recognizing, I usually use 10 just as a safe maximum. It would be best to put your array in the class that is the InputProcessor, which seems to be your Player class although it is typically the game class. Your touchDown, touchDragged and touchUp methods would change the values of x, y, and down for the Pointer at its index in touches[]. Then in update() iterate through the array and check for each touch.

For example:

@Override
public boolean touchDown(int screenX, int screenY, int pointer, int button) {
    if (pointer < touches.length){
        touches[pointer].x = screenX;
        touches[pointer].y = screenY;
        touches[pointer].down = true;
        return true;
    }
    return false;
}

@Override
public boolean touchUp(int screenX, int screenY, int pointer, int button) {
    if (pointer < touches.length){
        touches[pointer].x = screenX;
        touches[pointer].y = screenY;
        touches[pointer].down = false;
        return true;
    }
    return false;

@Override
public boolean touchDragged(int screenX, int screenY, int pointer, int button) {
    if (pointer < touches.length){
        touches[pointer].x = screenX;
        touches[pointer].y = screenY;
        return true;
    }
    return false;
}

Side Notes: It seems like your update() method would only work with a fixed framerate, which may make movement speeds different on different devices unless a fixed framerate loop is implemented elsewhere in the code. In addition, you may want to move Gdx.input.setInputProcessor(this) to the constructor of the Player class.