CODEWITHSUNDEEP
javalibgdx
lexpfb
lexpfb

Reputation: 175

Instance variable resetting their value

This code is showing strange behavior. The BaseActor class just call in order: initPhysics, initGraphics and onCreate (only once) and then act (for each frame). The expected behaviors is that in onCreate method I hold the fixX value (that actually is -6) to use the this value to set the X position of object each frame, for make the X axis of object static. I put a debug point in onCreate and act and he is called appropriately. When 

fixX = getBody().getPosition().x;

he get value 6, as expected, but in act the fixX value back to 0. When I change the fixX variable to static, the things works like expected. I don't realize how. I put a System out on the constructor of BirdActor to be sure the object is create only once. The methods setTransform of body is an Jni interface for C++ code of Libgdx with Box2d Engine. 

public class BirdActor extends BaseActor {


   private float fixX = 0;

    public BirdActor() {
        System.out.println("Created");
    }

    @Override
    protected Body initPhysics() {
        return Assets.scene.getNamed(Body.class, "bird").get(0);
    }

    @Override
    protected void onCreate() {
        fixX = getBody().getPosition().x;
    }

    @Override
    public void act() {
        getBody().setTransform(fixX, getBody().getPosition().y, 0);
        super.act();


    }

    @Override
    protected Sprite initGraphics() {
        Sprite sprite = new Sprite(Assets.textureBird);
        return sprite;
    }

}

Upvotes: 1

Views: 203

Answers (1)

desertkun
desertkun

Reputation: 1037

The problem could be because you call virtual method in constructor.

So the call list is: 

1. BaseActor()
2. onCreate() of BirdActor
3. BirdActor() whitch inits the fixX = 0.

So initializing fixX is called after onCreate() method. Try remove the fixX initialization (= 0).

Upvotes: 1

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