日期:2014-05-20  浏览次数:20658 次

关于Java中repaint()的问题
问个关于Java中repaint()的问题:
调用display()时打印出GamePanel's display! 但不显示GamePanel's PrintComponent,也就是System.out.println("GamePanel's PrintComponent")这条语句没有执行,repaint()方法为什么不能调用 printComponent(Graphics g)方法。
Java code

import java.awt.Graphics;
import javax.swing.JPanel;

public class RepaintDemo 
{
    public static void main(String args[])
    {
        GamePanel gamepanel = new GamePanel();
        gamepanel.display();
    }
}

class GamePanel extends JPanel
{
    public void display()
    {
        System.out.println("GamePanel's display!");
        this.repaint();
    }    
    
    protected void printComponent(Graphics g) {
        // TODO Auto-generated method stub
        System.out.println("GamePanel's PrintComponent");    
    }    
}






------解决方案--------------------

这个组件都没有显示, 怎么会调用printComponent?
------解决方案--------------------
repaint()的自动调用过程是这样的:repaint()-->update()-->paint()
而不会自动调用printComponent()