public class TestGame extends Game {
    public SpriteBatch batch;
//    public MenuGame menuGame;
    public NewGame newGame;
    public GameOver gameOver;

    @Override
    public void create() {


        batch = new SpriteBatch();
//        menuGame = new MenuGame(this);
        newGame = new NewGame(this);
        gameOver = new GameOver(this);
    }

    @Override
    public void render() {
        super.render();
        chooseScreen();
    }

    public void chooseScreen() {
        if (Gdx.input.isKeyJustPressed(Input.Keys.NUM_1)) {
            setScreen(new MenuGame(this));
        }
        if (Gdx.input.isKeyJustPressed(Input.Keys.NUM_2) && getScreen() != newGame) {
            setScreen(newGame);
        }
        if (Gdx.input.isKeyJustPressed(Input.Keys.NUM_3) && getScreen() != gameOver) {
            setScreen(gameOver);
        }
    }
}

//------------------------------------------------------------------------------------------

public class MenuGame implements Screen {
    Texture menuImage;
    TestGame screen;
    Music music;

    public MenuGame(TestGame screen) {
        music = Gdx.audio.newMusic(Gdx.files.internal("firstMusic.mp3"));
        menuImage = new Texture(Gdx.files.internal("first.png"));
        this.screen = screen;
    }

    @Override
    public void show() {
        music.setLooping(true);
        music.play();
    }

    @Override
    public void render(float delta) {
        screen.batch.begin();
        screen.batch.draw(menuImage, 0, 0);
        screen.batch.end();
    }

    @Override
    public void hide() {
        music.stop();
        dispose();
    }

    @Override
    public void dispose() {
        menuImage.dispose();
        music.dispose();
    }
}

//--------------------------------------------------------------------------------------------

public class NewGame implements Screen {
    Texture newGameImage;
    TestGame screen;
    Music music;

    public NewGame(TestGame screen) {
        music = Gdx.audio.newMusic(Gdx.files.internal("secondMusic.mp3"));
        newGameImage = new Texture(Gdx.files.internal("second.jpg"));
        this.screen = screen;
    }

    @Override
    public void show() {
        music.setLooping(true);
        music.play();
    }

    @Override
    public void render(float delta) {
        screen.batch.begin();
        screen.batch.draw(newGameImage, 0, 0);
        screen.batch.end();
    }