舞台将不会在 libgdx 中呈现,出现空指针错误

Stage will not render in libgdx, get null pointer error

我只是想让 Actor 和 Stage 正常工作以设置基本流程,然后从那里继续。我每次都会得到一个指向舞台的空指针,请帮忙。 Paddle 和 Ball class 现在完全相同,Assets 是用于加载纹理的静态 class。

public class MyGame implements ApplicationListener {
public final static int WIDTH = 480;
public final static int HEIGHT = 800;
private Stage stage;
private Paddle paddle;
private Ball ball;




@Override
public void create () {
    Assets.load();
    Stage stage = new Stage(new ScreenViewport());
    paddle = new Paddle();
    ball = new Ball();
    stage.addActor(paddle);
    stage.addActor(ball);


}

@Override
public void render() {
    Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

    stage.draw();

}

@Override
public void pause() {

}

@Override
public void resume() {

}

@Override
public void resize(int width, int height){
    stage.getViewport().update(width,height,true);

}

@Override
public void dispose(){
    Assets.dispose();
    stage.dispose();


}

public int getWidth(){return WIDTH;}
public int getHeight(){return HEIGHT;}

}

public class Paddle extends Actor {


Rectangle bounds;


public Paddle(){

    setPosition(150,10);


}

@Override
public void act(float delta){

}


public void draw(Batch batch , float parentAlpha){

    batch.draw(Assets.paddle,150,10 );
}

private void updateBounds() {bounds.set(getX(), getY(), getWidth(), getHeight());
}
public Rectangle getBounds() {
    return bounds;
}

}

问题是,您在 create 方法中创建了一个 Stage,但您从未将其分配给您的私有成员 stage
所以不要在 create 中写 Stage stage = new Stage() 只需写 stage = new Stage().
还要记住将 Exception 和它的 Stack Trace 添加到您的 SO-Question 中,并标记 Exception 似乎出现的行。这将使每个想要提供帮助的人都更容易。

删除同一变量的第二个阶段声明"stage"

@Override
public void create () {
    Assets.load();
    stage = new Stage(new ScreenViewport()); 
    paddle = new Paddle();
    ball = new Ball();
    stage.addActor(paddle);
    stage.addActor(ball);


}