第一步，界面上画出英雄生命值
    FlyPanel 类中
    /*
     画出生命值和分数
    *     @param g
    */
    _private void paintLifeAndScore(Graphics g){
    g.setColor(new Color(0xFF00000));
    g.setFont(new Font(Font._SANS_SERIF    ,Font.BOLD,20));
    g.drawString(“LIFE:”+hero.getLife(),20,45);
    }
    //当前游戏状态
    public static GameState gameState = GameState.START;

    @Override
    public void paint(Graphics g) {
    g.drawImage(background, x, y, bgWidth, bgHeight, null);
    paintState(g);
    hero.draw(g);
    for (Bullet bullet : bulletList) {
    bullet.draw(g);
    bullet.up();
    }
    for (FlySprite flySprite : enemys) {
    flySprite.draw(g);
    ActionSprite actionSprite = (ActionSprite) flySprite;
    actionSprite.down();
    }
    paintLifeAndScore(g);
    }
    Hero类当中
    @Override
    public void destroy() {
    //表示游戏结束
    FlyPanel.gameState = GameState.GAME_OVER;
    }
    FlyPanel 类中
    /*
     根据当前的游戏状态进行绘制图片
    *     @param g
    */
    _private void paintState(Graphics g) {
    switch (_gameState    ) {
    case START:
    g.drawImage(start, 0, 0, null);
    break;
    case PAUSE:
    g.drawImage(pause, 0, 0, null);
    break;
    case GAME_OVER:
    //清理现场 游戏内容的重置
    hero = new Hero();
    enemys.clear();
    bulletList.clear();
    pauseGameTask();
    g.drawImage(gameover, 0, 0, null);
    //gameState = GameState.START;
    break;
    }
    }

    //添加事件，改变游戏状态
    super.addMouseListener(new MouseAdapter() {
    @Override
    public void mouseClicked(MouseEvent e) {
    switch (gameState) {
    //当游戏状态是START 点击 变成RUNNING
    case START:
    case PAUSE:
    gameState = GameState.RUNNING;
    startGameTask();
    break;
    case RUNNING:
    gameState = GameState.PAUSE;
    pauseGameTask();
    repaint();
    break;
    case GAME_OVER:
    gameState = GameState.START;
    repaint();
    break;
    }
    }
    });