如何创建libgdx主菜单屏幕 [英] How to create libgdx main menu screen

问题描述

我是java和libgdx的新手，我想创建一个主菜单屏幕，有人可以给我一个简单的例子吗？

I'm new to java and libgdx and I want to create a main menu screen, Can someone give me a simple example?

推荐答案

你所要求的是非常广泛的，它涉及许多元素，如创建按钮，皮肤，设置表等等。无论如何你应该使用Screens，添加一个舞台并在舞台上添加actor。最终，您需要将Listeners添加到按钮actor以切换屏幕。这是我为你做的一个：

What you are asking is very broad, it involves many elements like creating buttons, skins, setting up Tables, etc. Anyway you should use Screens for this, add a stage and add actors to the stage. Eventually you need to add Listeners to your button actors to switch screens. Here is one I made for you:

public class TestScreen implements Screen{

    private SpriteBatch batch;
    protected Stage stage;
    private Viewport viewport;
    private OrthographicCamera camera;
    private TextureAtlas atlas;
    protected Skin skin;

    public TestScreen()
    {
        atlas = new TextureAtlas("skin.atlas");
        skin = new Skin(Gdx.files.internal("skin.json"), atlas);

        batch = new SpriteBatch();
        camera = new OrthographicCamera();
        viewport = new FitViewport(Constants.WorldWidth, Constants.WorldHeight, camera);
        viewport.apply();

        camera.position.set(camera.viewportWidth / 2, camera.viewportHeight / 2, 0);
        camera.update();

        stage = new Stage(viewport, batch);    
    }


    @Override
    public void show() {
        //Stage should controll input:
        Gdx.input.setInputProcessor(stage);

        //Create Table
        Table mainTable = new Table();
        //Set table to fill stage
        mainTable.setFillParent(true);
        //Set alignment of contents in the table.
        mainTable.top();

        //Create buttons
        TextButton playButton = new TextButton("Play", skin);
        TextButton optionsButton = new TextButton("Options", skin);
        TextButton exitButton = new TextButton("Exit", skin);

        //Add listeners to buttons
        playButton.addListener(new ClickListener(){
            @Override
            public void clicked(InputEvent event, float x, float y) {
                ((Game)Gdx.app.getApplicationListener()).setScreen(new PlayScreen());
            }
        });
        exitButton.addListener(new ClickListener(){
            @Override
            public void clicked(InputEvent event, float x, float y) {
                Gdx.app.exit();
            }
        });

        //Add buttons to table
        mainTable.add(playButton);
        mainTable.row();
        mainTable.add(optionsButton);
        mainTable.row();
        mainTable.add(exitButton);

        //Add table to stage
        stage.addActor(mainTable);
    }

    @Override
    public void render(float delta) {
        Gdx.gl.glClearColor(.1f, .12f, .16f, 1);
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

        stage.act();
        stage.draw();
    }

    @Override
    public void resize(int width, int height) {
        viewport.update(width, height);
        camera.position.set(camera.viewportWidth / 2, camera.viewportHeight / 2, 0);
        camera.update();
    }

    @Override
    public void pause() {

    }

    @Override
    public void resume() {

    }

    @Override
    public void hide() {

    }

    @Override
    public void dispose() {
        skin.dispose();
        atlas.dispose();
    }
}

我称之为的方式是更改初始课程一点。

The way I call this is by changing the initial class a bit.

//Let the class extend from game
public class MyGame extends Game()
{
    //Delete everything in it and leave a create() with a single line
    @Override
    public void create() {
    setScreen(new MenuScreen());
    }
}

当然要使上面的代码工作，你需要设置 Skin 和 Atlas 以绘制按钮。但是，您可以只添加图像和字体并手动创建按钮。无论如何，我只是回答了一个问题深入创建皮肤和 Atlas 。

Of course to make the above code work you need to setup a Skin and Atlas for drawing the buttons. You could however just add a image and a font and create your buttons manually. Anyway, I just answered a question where I go in depth on creating a Skin and Atlas.

编辑虽然已经询问了菜单类的示例，但用户提问者实际上只需知道如何从屏幕切换到屏幕。有点尴尬但是只是花了几分钟写了上面的代码;）。

Edit Although an example of a menu class has been asked the user asker actually just needed to know how to switch from screen to screen. A bit awkward but luckely writing the above code just took a couple of minutes ;).

你可以随时访问 ApplicationListener 从任何地方使用 Gdx.app.getApplicationListener 。您可以将其转换为游戏以访问 setScreen 。

You can always access the ApplicationListener from anywhere using Gdx.app.getApplicationListener. You can cast this to Game to access setScreen.

((Game)Gdx.app.getApplicationListener()).setScreen(new GameScreen());

或者您可以手动传递初始Game对象或applicationListener。确保新屏幕接受游戏对象。

Or you could pass along the initial Game object or applicationListener by hand. Make sure the new screen accepts the game object.

public class MenuScreen
{
    private Game gameObject;
    public MenuScreen(Game gameObject)
    {
        this.gameObject = gameObject;
    }
    private void someMethod()
    {
         //Switches to a new MenuScreen... 
         //useless in most cases but you get the idea
         gameObject.setScreen(new MenuScreen(gameObject);
    }
}

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