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我想每 x 秒更改一次菜单的背景图像。我正在使用 libGDX scene2D.ui 来制作菜单。TestScreen 类扩展了 AbstractScreen 抽象类，它实现了 libGDX 的 Screen 类。问题：通过堆栈上的 Table 对象将图像加载到舞台后，将图像引用更改为不同的图像没有任何作用。Stage.draw() 毫不在意，就好像它复制了我的原始图像一样。我想将背景保留为 Image 类并通过 stage.draw() 进行渲染。

更复杂的是，如果我在 render() 方法中将图像更改为另一个图像，那么 image.setVisible(false) 也会停止工作。

public class TestScreen extends AbstractScreen {

private Stage stage;
private Image background;
private boolean ChangeBackground = true;
private final float refreshTime = 2.0f; // refresh to new image every 2 seconds.
private float counter = refreshTime;

public TestScreen(Game game) {
    super(game);
}

@Override
public void render(float deltaTime) {
    Gdx.gl.glClearColor(0.0f, 0.0f, 0.0f, 1.0f);
    Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT);

    if(ChangeBackground){
        counter -= deltaTime;
        if(counter < 0){
            counter = refreshTime;
            // Assets class has the 12 images loaded as "Image" objects already.
            // I simple want to change the reference to other (already loaded in memory images) ...
            // and make stage render the new image.
            background = Assets.instance.wallpapers[(int) (Math.random()*12)];  // The image should change.
            //background.setVisible(false);
        }
    }
    stage.act(deltaTime);
    stage.draw();
}

@Override
public void resize(int width, int height) {
    stage.setViewport(Constants.VIEWPORT_GUI_WIDTH, Constants.VIEWPORT_GUI_HEIGHT, false);
}
@Override
public void show() {
    stage = new Stage();
    Gdx.input.setInputProcessor(stage);
    makeStage();
}
@Override
public void hide() {
    stage.dispose();
}
@Override
public void pause() {   
}

// Builds the Background later and adds it to a stage through a stack.
// This is how it's done in my game. I made this test bench to demonstrate.
private void makeStage() {
    Table BackGroundLayer = new Table();
    background = Assets.instance.wallpapers[(int) (Math.random()*12)];
    BackGroundLayer.add(background);

    Stack layers = new Stack();
    layers.setSize(800, 480);
    layers.add(BackGroundLayer);

    stage.clear();
    stage.addActor(layers);
}

}

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1 回答 1

7

Image是 的子类Actor。主要区别在于，它Image有一个Drawable内部。如果您调用 ，这Drawable将被绘制stage.draw()，它调用draw()of Image。Image您可以Drawable通过使用更改而不是更改setDrawable(Drawable param);。什么是Drawable? 它是任何实现Drawable接口的类，例如TextureRegionDrawable. 如果您正在使用TextureRegions ，则可以使用此构造函数：TextureRegionDrawable(TextureRegion region);. 也许将背景图像存储在Drawable数组中会更好，这样每次设置新的Drawable. 示例代码：

TextureRegionDrawable[] images = new TextureRegionDrawable[12];
for (int i = 0; i<12; i++) {
    images[i] = new TextureRegionDrawable(Assets.instance.textureRegions[i]);
}

然后在你的渲染中：

if(changeBackground) {
   counter -= delta;
   if (counter < 0) {
       counter = refreshtime
       background.setDrawable(images[(int)(Math.random()*12)]);
   }
}

这应该工作

于 2014-02-07T13:08:29.623 回答