Java 如何在MT4J框架中设置组件重心，就像我提供链接的视频一样？

视频访问（）

我想让组件的行为像这样，如果我拖动任何组件并将其放到屏幕上的任何位置，那么它应该像视频一样平滑地返回到屏幕的中心。我可以在屏幕上的任何特定位置设置任何组件，但无法在中间再次返回它们。 代码是

public class Physics extends AbstractScene 
{   
    private float timeStep = 1.0f / 60.0f;
    private int constraintIterations = 10;

    private int windowWidth=MT4jSettings.getInstance().windowWidth;
    private int windowHeight= MT4jSettings.getInstance().windowHeight;

    /** THE CANVAS SCALE **/
    private float scale = 20;
    private AbstractMTApplication app;
    public World world;

    private MTComponent physicsContainer;

    PhysicsRectangle physRect;
    PhysicsRectangle borderLeft, borderRight, borderTop, borderBottom;
    Vector3D pos;

    Vec2 gravity1;
    AABB worldAABB;
    public Physics(AbstractMTApplication mtApplication, String name)
    {
        super(mtApplication, name);
        this.app = mtApplication;

        float worldOffset = 600; 

        worldAABB = new AABB(new Vec2(-worldOffset, -worldOffset), new Vec2((app.width)/scale + worldOffset, (app.height)/scale + worldOffset));

        gravity1 = new Vec2(0, 30);
        boolean sleep = false;
        //Create the pyhsics world
        this.world = new World(worldAABB, gravity1, sleep);
        this.registerGlobalInputProcessor(new CursorTracer(app, this));
        this.registerPreDrawAction(new UpdatePhysicsAction(world, timeStep, constraintIterations, scale));

        physicsContainer = new MTComponent(app);

        physicsContainer.scale(scale, scale, 1, Vector3D.ZERO_VECTOR);
        this.getCanvas().addChild(physicsContainer);

        //Create borders around the screen
        this.createScreenBorders(physicsContainer);

        //Createa Rectangles
        for (int i = 0; i < 5; i++) 
        {
            pos = new Vector3D(windowWidth/2f, windowHeight/2f);
            physRect = new PhysicsRectangle(pos, 100, 100, app, world, 1f, 0.4f, 0.4f, scale);
            MTColor col = new MTColor(ToolsMath.getRandom(60, 255),ToolsMath.getRandom(60, 255),ToolsMath.getRandom(60, 255));
            physRect.setFillColor(col);
            physRect.setStrokeColor(col);
            PhysicsHelper.addDragJoint(world, physRect, physRect.getBody().isDynamic(), scale);
            physicsContainer.addChild(physRect);
        }       
    }

    private void createScreenBorders(MTComponent parent)
    {
        //Left border 
        float borderWidth = 50f;
        float borderHeight = app.height;
        Vector3D pos = new Vector3D(-(borderWidth/2f) , app.height/2f);
        borderLeft = new PhysicsRectangle(pos, borderWidth, borderHeight, app, world, 0,0,0, scale);
        borderLeft.setName("borderLeft");
        parent.addChild(borderLeft);
        //Right border
        pos = new Vector3D(app.width + (borderWidth/2), app.height/2);
        borderRight = new PhysicsRectangle(pos, borderWidth, borderHeight, app, world, 0,0,0, scale);
        borderRight.setName("borderRight");
        parent.addChild(borderRight);
        //Top border
        borderWidth = app.width;
        borderHeight = 50f;
        pos = new Vector3D(app.width/2, -(borderHeight/2));
        borderTop = new PhysicsRectangle(pos, borderWidth, borderHeight, app, world, 0,0,0, scale);
        borderTop.setName("borderTop");
        parent.addChild(borderTop);
        //Bottom border
        pos = new Vector3D(app.width/2 , app.height + (borderHeight/2));
        borderBottom = new PhysicsRectangle(pos, borderWidth, borderHeight, app, world, 0,0,0, scale);
        borderBottom.setName("borderBottom");
        parent.addChild(borderBottom);
    }   

    public void onEnter() {
    }

    public void onLeave() { 
    }
}

我也试过什么？

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1.我试图应用线程，但我们不能在MT4J中使用线程（我在一个网站上发现了这个），线程的替换是一个接口IPreDrawAction。我应用了这个，但还有一个问题，我们不能在物理组件上应用这个接口，所以我使用了MTComponent，但还有一个问题，我们不能在MTComponent上应用重力。

这里有人可以帮助我吗？

public class staertWaterApp extends MTApplication 
{
    private static final long serialVersionUID = 1L;
    public static void main(String[] args) {
        initialize();
    }
    @Override
    public void startUp() 
    {
        addScene(new Physics(this, "Physics Example Scene"));
    }
}