如何在java中调用其他方法中的Graphics2D方法？

Question

如何在游戏方法中调用paint方法？

如果我用命令调用“new paint（）;”它不起作用

// Main
public Game() {
    super();
    setTitle("Breakout");
    setDefaultCloseOperation(EXIT_ON_CLOSE);
    setSize(500, 500);
    setLocationRelativeTo(null);
    setIgnoreRepaint(true);
    setResizable(false);
    setVisible(true);
}

// Grafica
class paint extends JPanel {

    public paint(Graphics2D g) {
        super.paint(g);
        g.setColor(Color.black);

    }

}

Answer 1

大多数程序员在JPanel超类中使用受保护的swing方法paintComponent（Graphics g）来匿名调用repaint（）来改变游戏值并改变组件的视觉外观。使用SwingTimer将在预定的时间内更新结果。

public class game extends JPanel implements ActionListener{

      int camX, camY;
      int update_time = 5;// in milliseconds...
      Graphics2D g2d;
      Image image;
      Timer t;

     public game(){

          t = new Timer(update_time, this);// given "this" is an ActionListener...
          t.start();// calls actionPerformed method every 5ms...

     }


     public void actionPerformed(ActionEvent e){

            repaint();//calls paintComponent() method...

     }


      public void paintComponent(Graphics g){

          super.paintComponent(g);
          g2d = (Graphics2D)g;

          g2d.drawImage(image, camX, camY, this);
          //Do graphical stuff
      }



}