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如何在一JFrame中画图,不覆盖原有东西

热度:71   发布时间:2016-04-23 21:33:00.0
怎么在一JFrame中画图,不覆盖原有东西

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

public class Draw extends JFrame{
JPanel  jPanel=new JPanel();
public Draw() {

            jPanel.setBackground(Color.red);
            add(jPanel); 
   Drawation drawaction=new Drawation();//添加画图,把上面jpanel的设置给覆盖了;要是先添加画图再添加
   add(drawaction);                    //jpanel则把画图覆盖了
  
}
public static void main(String[] args){
             Draw draw=new Draw();
         draw.setTitle("abc");
    draw.setSize(300,300);
    draw.setVisible(true);
    draw.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

}

}
class Drawation extends JPanel{
   public void paintComponent(Graphics g){
     super.paintComponents(g);
 g.drawString("agagh", 50, 45);
   }
}
这只是一段简单的验证代码,没什么意义。就是想了解怎么才能在动态画图的同时可以保留原有jpanel上的各种组件,而且可以在其上画图

------解决方案--------------------
JLayer 的例子。JXLayer(从 swinglabs网站下载)的类似,JLayer就是 JXLayer整合到java 7的结果。
import javax.swing.*;
 import javax.swing.plaf.LayerUI;
 import java.awt.*;

 public class JLayerSample {

     private static JLayer<JComponent> createLayer() {
         // This custom layerUI will fill the layer with translucent green
         // and print out all mouseMotion events generated within its borders
         LayerUI<JComponent> layerUI = new LayerUI<JComponent>() {

             public void paint(Graphics g, JComponent c) {
                 // paint the layer as is
                 super.paint(g, c);
                 // fill it with the translucent green
                 g.setColor(new Color(0, 128, 0, 128));
                 g.fillRect(0, 0, c.getWidth(), c.getHeight());
             }

             public void installUI(JComponent c) {
                 super.installUI(c);
                 // enable mouse motion events for the layer's subcomponents
                 ((JLayer) c).setLayerEventMask(AWTEvent.MOUSE_MOTION_EVENT_MASK);
             }

             public void uninstallUI(JComponent c) {
                 super.uninstallUI(c);
                 // reset the layer event mask
                 ((JLayer) c).setLayerEventMask(0);
             }

             // overridden method which catches MouseMotion events
             public void eventDispatched(AWTEvent e, JLayer<? extends JComponent> l) {
                 System.out.println("AWTEvent detected: " + e);