用Graphics画图,怎么重绘?

Question

public void paint(Graphics g){
    g.fillOval(250, 170, 220, 220);
}
当移动别的窗口覆盖所画的图之后又把窗口移走,被覆盖掉的就不会被重绘了,怎么实现重绘?

Answer 1

http://fronkx.blog.hexun.com/12407600_d.html

Answer 2

用repaint(),当启用它时,它会自动重新调用 paint(Graphics g)函数.

Answer 3

//新曙光培训@西安
//www.xinshuguang.org
import   javax.swing.*;   
import   java.awt.*;   
import   java.awt.geom.Rectangle2D;   
import   java.awt.Graphics2D;   
public class xsgJuXing
{
   public static void main(String[] args)
   {
      EventQueue.invokeLater(new Runnable()
         {
            public void run()
            {
               JuXingFrame frame = new JuXingFrame();
               frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
               frame.setVisible(true);
            }
         });
   }
}class JuXingFrame extends JFrame
{
   public JuXingFrame()
   {
      setTitle("新曙光培训@西安");
      setSize(DEFAULT_WIDTH, DEFAULT_HEIGHT);      // add panel to frame      JuXingPanel panel = new JuXingPanel();
      add(panel);
   }
   public static final int DEFAULT_WIDTH = 250;
   public static final int DEFAULT_HEIGHT = 200;
}
class JuXingPanel extends JPanel
{
   public   void   paintComponent(Graphics   g)   {  
  //当组件需要重画时，paintComponent被自动调用 
          super.paintComponent(g);   
          Rectangle2D   rect   =   new   Rectangle2D.Double(100,   100,   10,   50);   
            Rectangle2D   ect   =   new   Rectangle2D.Double(100,   100,   10,   50);   
          Graphics2D   g2   =   (Graphics2D)   g;   
          g2.draw(ect);   
          g2.fill(rect);   
      }   
}
视频讲解

Answer 4

public class JFrame0 extends JFrame {    public JFrame0() {
        initComponents();
        this.add(new MyPanel(this));
        this.setLocationRelativeTo(null);
    }
}class MyPanel extends JPanel{
    JFrame0 mf = null;
    private float PI = 3.1415926f;
    public MyPanel(JFrame0 mf){
        this.mf = mf;
    }
    
    @Override
    public void paint(Graphics g){
        super.paint(g);
        g.fillOval(250, 170, 220, 220);
    }
    
    public void repaint(Graphics g){
        super.repaint();
    }
}我这样写就什么都不画.......

Answer 5

当然是repaint了，还有你改变窗口大小时会自动重画，你试试看最小化然后还原也会自动重画

Answer 6

main函数有无没贴出来大家说的repaint是不是重载repaint?或者是把repaint放到paint里面循环调用
我现在是想当需要重绘时就重绘,我上面的代码连paint都没实现...