创建屏幕控制Libgdx

Question

我正在使用libgdx。我正在使用此示例https://github.com/oakes/libgdx-examples/tree/master/SuperKoalio/core/src/net/sekao/superkoalio来创建游戏。

我想在屏幕上添加控件，以便用户可以使用按钮向左，向右，向上移动。我使用了这个“控制器”类https://github.com/BrentAureli/ControllerDemo/tree/master/core/src/com/brentaureli/overlaydemo

但是我无法在屏幕上看到任何控件。任何人都可以提供解决方案来解决这个问题。

public class MainScreen implements Screen {
    Stage stage;
    TiledMap map;
    OrthogonalTiledMapRenderer renderer;
    OrthographicCamera camera;
    Koala koala;
    Controller controller;

    public void show() {
        map = new TmxMapLoader().load("level1.tmx");
        final float pixelsPerTile = 16;
        renderer = new OrthogonalTiledMapRenderer(map, 1 / pixelsPerTile);
        camera = new OrthographicCamera();
        controller = new Controller();

        stage = new Stage();
        stage.getViewport().setCamera(camera);

        koala = new Koala();
        koala.layer = (TiledMapTileLayer) map.getLayers().get("walls");
        koala.setPosition(20, 10);
        stage.addActor(koala);
    }

    public void render(float delta) {
        Gdx.gl.glClearColor(0.5f, 0.5f, 1, 1);
        Gdx.gl.glClear(GL20.GL_COLOR_BUFFER_BIT);

        camera.position.x = koala.getX();
        camera.update();

    if(Gdx.app.getType() == Application.ApplicationType.Android)
    controller.draw();

        renderer.setView(camera);
        renderer.render();

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

    public void dispose() {
    }

    public void hide() {
    }

    public void pause() {
    }

    public void resize(int width, int height) {
        camera.setToOrtho(false, 20 * width / height, 20);
        controller.resize(width, height);
    }

    public void resume() {
    }
}

控制器类：

public class Controller {
    Viewport viewport;
    Stage stage;
    boolean upPressed, downPressed, leftPressed, rightPressed;
    OrthographicCamera cam;

    public Controller(){
        cam = new OrthographicCamera();
        viewport = new FitViewport(800, 480, cam);
        stage = new Stage(viewport);

        stage.addListener(new InputListener(){

            @Override
            public boolean keyDown(InputEvent event, int keycode) {
                switch(keycode){
                    case Input.Keys.UP:
                        upPressed = true;
                        break;
                    case Input.Keys.DOWN:
                        downPressed = true;
                        break;
                    case Input.Keys.LEFT:
                        leftPressed = true;
                        break;
                    case Input.Keys.RIGHT:
                        rightPressed = true;
                        break;
                }
                return true;
            }

            @Override
            public boolean keyUp(InputEvent event, int keycode) {
                switch(keycode){
                    case Input.Keys.UP:
                        upPressed = false;
                        break;
                    case Input.Keys.DOWN:
                        downPressed = false;
                        break;
                    case Input.Keys.LEFT:
                        leftPressed = false;
                        break;
                    case Input.Keys.RIGHT:
                        rightPressed = false;
                        break;
                }
                return true;
            }
        });

        Gdx.input.setInputProcessor(stage);

        Table table = new Table();
        table.left().bottom();

        Image upImg = new Image(new Texture("flatDark25.png"));
        upImg.setSize(50, 50);
        upImg.addListener(new InputListener() {

            @Override
            public boolean touchDown(InputEvent event, float x, float y, int pointer, int button) {
                upPressed = true;
                return true;
            }

            @Override
            public void touchUp(InputEvent event, float x, float y, int pointer, int button) {
                upPressed = false;
            }
        });

        Image downImg = new Image(new Texture("flatDark26.png"));
        downImg.setSize(50, 50);
        downImg.addListener(new InputListener() {

            @Override
            public boolean touchDown(InputEvent event, float x, float y, int pointer, int button) {
                downPressed = true;
                return true;
            }

            @Override
            public void touchUp(InputEvent event, float x, float y, int pointer, int button) {
                downPressed = false;
            }
        });

        Image rightImg = new Image(new Texture("flatDark24.png"));
        rightImg.setSize(50, 50);
        rightImg.addListener(new InputListener() {

            @Override
            public boolean touchDown(InputEvent event, float x, float y, int pointer, int button) {
                rightPressed = true;
                return true;
            }

            @Override
            public void touchUp(InputEvent event, float x, float y, int pointer, int button) {
                rightPressed = false;
            }
        });

        Image leftImg = new Image(new Texture("flatDark23.png"));
        leftImg.setSize(50, 50);
        leftImg.addListener(new InputListener() {

            @Override
            public boolean touchDown(InputEvent event, float x, float y, int pointer, int button) {
                leftPressed = true;
                return true;
            }

            @Override
            public void touchUp(InputEvent event, float x, float y, int pointer, int button) {
                leftPressed = false;
            }
        });

        table.add();
        table.add(upImg).size(upImg.getWidth(), upImg.getHeight());
        table.add();
        table.row().pad(5, 5, 5, 5);
        table.add(leftImg).size(leftImg.getWidth(), leftImg.getHeight());
        table.add();
        table.add(rightImg).size(rightImg.getWidth(), rightImg.getHeight());
        table.row().padBottom(5);
        table.add();
        table.add(downImg).size(downImg.getWidth(), downImg.getHeight());
        table.add();

        stage.addActor(table);
    }

    public void draw(){
        stage.draw();
    }

    public boolean isUpPressed() {
        return upPressed;
    }

    public boolean isDownPressed() {
        return downPressed;
    }

    public boolean isLeftPressed() {
        return leftPressed;
    }

    public boolean isRightPressed() {
        return rightPressed;
    }

    public void resize(int width, int height){
        viewport.update(width, height);
    }
}