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JAVA 怎么清空或删除Canvas里的内容

热度:131   发布时间:2016-04-24 12:43:14.0
JAVA 如何清空或删除Canvas里的内容
JAVA 如何清空或删除Canvas里的内容

------解决方案--------------------
那给你一个例子吧
是清除JPanel的内容
和Canvas道理一样
一个面板上有字符串"HELLOWORLD!"
点击鼠标内容清除
调用repaint()如最小化再恢复
则字符串又显示

Java code
import java.awt.*;import java.awt.event.*;import javax.swing.*;public class TT{    public static void main(String[] args)    {        MFrame m = new MFrame();        m.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);        m.setVisible(true);    }}class MFrame extends JFrame{    public static final int Default_Width = 200;    public static final int Default_Height = 200;        public MFrame()    {        setBounds(100, 100, Default_Width, Default_Height);                Container con = getContentPane();        MPanel p = new MPanel();        con.add(p);    }}class MPanel extends JPanel{    public MPanel()    {        addMouseListener(new                        MouseAdapter()                        {                            public void mouseClicked(MouseEvent e)                            {clearPanel();}                        });    }        public void paintComponent(Graphics g)    {        super.paintComponent(g);        g.drawString("HELLO WORLD!",30,30);    }        public void clearPanel()    {        Graphics g = getGraphics();        int width = (int)(getBounds().getWidth());        int height = (int)(getBounds().getHeight());        g.clearRect(0, 0, width, height);    }}
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