无法在Libgdx中显示文本

Posted 2021-04-20

我正在使用Libgdx制作一款安卓游戏。我是新手，我无法找到，为什么我的命令font.draw（）中的文本没有显示。一直在努力，直到我为这个游戏添加一个舞台。我在代码顺序中也有上层sb.begin（）;

我在谷歌上搜索了很多，我发誓我花了至少4个小时谷歌搜索，但都没有成功。

如果有人能帮助我，我将非常感激。

非常感谢您的回复！

        sb.draw(gameoverImg, cam.position.x - gameoverImg.getWidth() / 2, cam.position.y + 95);
        sb.draw(table, cam.position.x - table.getWidth() / 2 + 33, cam.position.y - 180);


        font.getData().setScale(0.25f);
        font.draw(sb, "" + currentHighScore, cam.position.x + 30, FlappyDemo2.HEIGHT / 2 - 200);
        font.draw(sb, "" + score, cam.position.x + 30, FlappyDemo2.HEIGHT / 2 - 159);




        myTextureRegion = new TextureRegion(playBtn2);
        myTexRegionDrawable = new TextureRegionDrawable(myTextureRegion);
        button = new ImageButton(myTexRegionDrawable); //Set the button up
        button.setPosition(253/2, 112);
        stage = new Stage(new ScreenViewport()); //Set up a stage for the ui
        stage.addActor(button); //Add the button to the stage to perform rendering and take input.


        myTextureRegion2 = new TextureRegion(scoreBtn);
        myTexRegionDrawable2 = new TextureRegionDrawable(myTextureRegion2);
        button2 = new ImageButton(myTexRegionDrawable2); //Set the button up
        button2.setPosition(345, 185);
        stage.addActor(button2);

答案

如果你认真对待编程从基础开始。如果这是你的更新方法，那么你正在创建一个new Stage和2 new ImageButton并在每帧加载纹理。如果你想到这一秒，你会发现这是错误的做法。使用new关键字是“昂贵的”，因为它创建了一个新对象。在我们的快速计算机上，这并不重要但最终会产生延迟。另外，如果你每一帧都创建一个新的舞台，你就不能用它来做很多事情......旧的每一帧都会被处理掉。您可以在更新循环之外执行此操作。

如果这不是您的更新方法，则将您绘制的行移动到更新方法。还要确保更新方法每帧都清除屏幕。这就是图形通常的工作方式，屏幕被清除的每一帧都被重新绘制。

我强烈建议你离开游戏编程并从基础java教程开始。这将使你的生活变得更加容易，因为你淹死的那一刻，如果你不采取这一步，将会有一段时间。我确实想指出你正确的方向，希望下面的代码是一个大开眼界。编程中最重要的部分是整洁地构建代码。一个超过10行的方法可以分成多个方法，并且更具可读性。

我总是使用Screen功能构建到LibGDX中来开始。

test screen.Java

/**
 * Extending from screen adapter to gain it's functionality and implement the Gesture Listener to use input.
 */
public class TestScreen extends ScreenAdapter implements GestureDetector.GestureListener {

    // Declare fields, here we reserve memory to put the objects in.
    // There is almost never a reason to make your fields public.
    // Expose them with getters and setters if you need too.
    private SpriteBatch spriteBatch;
    private Viewport viewport;
    private Stage stage;

    private BitmapFont font;

    /**
     * The constructor gets run whenever you use the new keyword.
     * This is a good place to initialize the fields.
     */
    public TestScreen() {
        spriteBatch = new SpriteBatch();

        // There are many viewports, this just sets the viewport to the size of the window width and
        // height. Note that most, if not all other viewports ask for worldWidth and worldHeight not
        // screenWidth and screenHeight.
        // It is also important to note that at this point when the code runs the window is not opened
        // yet so the viewport does not get any width. That is why we need to update it in the resize
        // method below, this will also make sure it does it's job when stretching the window.
        viewport = new ScreenViewport();
        viewport.apply();

        // Never load assets and textures in the game loop. Unless of course you let the player load
        // a image but then just load it once and not every frame.
        // I used a random font in my library with the size of 20 pixels.
        font = new BitmapFont(Gdx.files.internal("fonts/sarpanch_20.fnt"));


        // I put the stage setup in it's own method.
        stage = new Stage();
        setupStage();

        // Input multiplexer allows for multiple input sources. In this case we made this screen
        // a GestureListener and the stage also needs input if you want to press buttons.
        Gdx.input.setInputProcessor(new InputMultiplexer(
            new GestureDetector(this),
            stage
        ));
    }

    /**
     * This is already a fairly long method. I could have put the click listener in it's own method
     * so we could reuse it on other actors and the code will be more readable.
     */
    private void setupStage() {
        // Use clear instead of the new keyword whenever you can.
        stage.clear();

        // I advice to use the Skin functionality for actor elements. It works great when you know
        // what you are doing. For now, just a style object.
        Label.LabelStyle style = new Label.LabelStyle(font, Color.RED);

        // final makes sure you won't put a new object in the field. It is needed because I use it
        // in the listener/observer pattern below and that only runs when it observers a specific
        // event. Thus it needs to still be the same object.
        final Label label = new Label("Hello World", style);
        label.setPosition(100, 100);

        // Add awesome effect to label.
        label.addListener(new ClickListener() {
            @Override
            public void enter(InputEvent event, float x, float y, int pointer, Actor fromActor) {
                label.getStyle().fontColor = Color.BLUE;
            }

            @Override
            public void exit(InputEvent event, float x, float y, int pointer, Actor fromActor) {
                label.getStyle().fontColor = Color.RED;
            }
        });
        // Instead I could have moved this click listener to addHoverColor(Actor actor)... 
        // sure, the above code would remain similar but in here it would read.
        // addHoverColor(label);
        // Which is much more readable.

        // add the Label actor to stage.
        stage.addActor(label);
    }

    /**
     * render is the game loop. delta is the time since previous frame.
     * @param delta
     */
    @Override
    public void render(float delta) {
        super.render(delta);

        // Unfortunately LibgDX couples logic and drawing in this method.
        // Always remember to do the logic first and then render
        // Let's make 2 methods for that to keep the code neat and decoupled.
        update(delta);
        draw();

        //I use Stage to draw my GUI, the logic goes in update but the gui is always drawn on top
        drawGui();
    }


    private void update(float delta) {
        stage.act();
    }

    private void draw() {
        //Clear screen and fill it with color.
        Gdx.gl.glClearColor(.05f, .05f, .05f, 1);
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

        // I want to be able to move the camera around so the sprite batch needs to know it projection
        spriteBatch.setProjectionMatrix(viewport.getCamera().combined);

        spriteBatch.setColor(Color.RED);

        spriteBatch.begin();
        //Use the SpriteBatch to draw the font.
        font.draw(spriteBatch, "Hello World", 100, 100);
        spriteBatch.end();

        //System.out.println(viewport.getCamera().viewportWidth);

    }

    private void drawGui() {
        stage.draw();
    }

    /**
     * resize is called whenever the window changes size. So also at the start when the window is
     * being set to your or default config size.
     * @param width
     * @param height
     */
    @Override
    public void resize(int width, int height) {
        super.resize(width, height);
        viewport.update(width, height);
    }

    // Screen adapter also has pause(), resume() and dispose(). But I leave those for now.


    // Following the mandatory methods from the GestureListener. I just use pan to move the camera around
    @Override
    public boolean touchDown(float x, float y, int pointer, int button) {
        return false;
    }

    @Override
    public boolean tap(float x, float y, int count, int button) {
        return false;
    }

    @Override
    public boolean longPress(float x, float y) {
        return false;
    }

    @Override
    public boolean fling(float velocityX, float velocityY, int button) {
        return false;
    }

    @Override
    public boolean pan(float x, float y, float deltaX, float deltaY) {
        viewport.getCamera().translate(-deltaX, deltaY, 0);
        viewport.getCamera().update();
        return false;
    }

    @Override
    public boolean panStop(float x, float y, int pointer, int button) {
        return false;
    }

    @Override
    public boolean zoom(float initialDistance, float distance) {
        return false;
    }

    @Override
    public boolean pinch(Vector2 initialPointer1, Vector2 initialPointer2, Vector2 pointer1, Vector2 pointer2) {
        return false;
    }

    @Override
    public void pinchStop() {

    }
}

现在我们只需要对主要核心类进行一些小改动。

// Extend from game instead of application listener
public class MyGame extends Game {

    @Override
    public void create () {
        // Now you have access to setScreen.
        setScreen(new TestScreen());
    }
}

我希望这是有道理的。它简短而简单，我确信在阅读你的代码时你可以阅读我的代码。所以让我再次按下，编写简洁的代码是编程的最重要方面。不仅对我们而且对你自己也是如此。显然，对语言有扎实的基础知识有助于此。