How to create libgdx main menu screen [closed]

问题

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

回答1:

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();
    }
}

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());
    }
}

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.

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 ;).

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());

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);
    }
}

来源：https://stackoverflow.com/questions/32451921/how-to-create-libgdx-main-menu-screen

标签

java

libgdx