contenPane小问题

[qojnbbqtg]

import java.awt.*;
import java.awt.event.*;
import javax.swing.*;


public class MouseMotionEventDemo1 extends JFrame implements MouseListener,MouseMotionListener{
	private static final long serialVersionUID = 1L;
	
	int flag;//flag=1代表MouseMoved,flag=2代表MouseDragged
	int x = 0;
	int y = 0;
	int startx,starty,endx,endy;//起始坐標與綹坐標
	
	public MouseMotionEventDemo1(){
		Container contentPane = getContentPane();
		contentPane.addMouseListener(this);
		contentPane.addMouseMotionListener(this);
		//setSize(300,300);
		setVisible(true);
		contentPane.setBackground(Color.white);
		addWindowListener(
				new WindowAdapter(){
					public void windowClosing(WindowEvent e){
						System.exit(0);
					}
				}
			);
	}
	//由mousePressed(),mouseReleased()取得拖曳的開始與結束坐標
	public void mousePressed(MouseEvent e){
		startx = e.getX();
		starty = e.getY();
	}
	public void mouseReleased(MouseEvent e){
		endx = e.getX();
		endy = e.getY();
	}
	public void mouseEntered(MouseEvent e){
		
	}
	public void mouseExited(MouseEvent e){
		
	}
	public void mouseClicked(MouseEvent e){
		
	}
	//mouseMoved(),mouseDragged()取得鼠標移動的每一個坐標，應調用repaint()方法
	public void mouseMoved(MouseEvent e){
		flag = 1;
		x = e.getX();
		y = e.getY();
		repaint();
	}
	public void mouseDragged(MouseEvent e){
		flag = 2;
		x = e.getX();
		y = e.getY();
		repaint();
	}
	public void update(Graphics g){
		//g.setColor(this.getBackground());
		//g.setColor(Color.white);
		//g.fillRect(0, 0, getWidth(), getHeight());
		//g.setColor(Color.red);
		paint(g);
	}
	public void paint(Graphics g){
		g.setColor(Color.red);
		if(flag==1){
			g.drawString("鼠標坐標：("+ x+","+y+")",10,50);
			g.drawLine(startx,starty,endx,endy);
		}
		if(flag==2){
			g.drawString("拖曳鼠標坐標：("+x+","+y+")" ,10, 50);
			g.drawLine(startx, starty, endx, endy);
		}
	}
	
	public static void main(String[] args){
		new MouseMotionEventDemo1();
	}
}

大家运行下看看是什么现象？为什么在我的机子上会出现contenePane是透明的，而且“拖曳鼠標坐標：("+x+","+y+")"”这些字都很模糊，，是我的机子卡的缘故吗？大家运行一下吧。。看看有没有出现我这种现象？

[afunx]

我找到原因了，好像是因为屏幕没有及时更新，和以前的字叠加造成的重影。正在试着解决。

[afunx]

public void paint(Graphics g){
//public Graphics2D createGraphics(){

// }
g.setColor(Color.white);//**改变之处**
g.fillRect(0, 0,getWidth(),getHeight());//**改变之处**
g.setColor(Color.red);
if(flag==1){
g.drawString("鼠标坐标：(" + x + "," + y + ")",10,50);
g.drawLine(startx,starty,endx,endy);
}
if(flag==2){
g.drawString("拖曳鼠标坐标：("+x+","+y+")" ,10, 50);
g.drawLine(startx, starty, endx, endy);
}
}
每次重绘时，要先把画板擦干净。

[qojnbbqtg]

谢谢 。。不过这样的话每次只能画一笔，有没有办法能每次画多笔啊。。。

[afunx]

哦。那你可以用下BufferedImage缓冲类。
把图形先画在缓冲上，在又缓冲画到画板上。而画板每次画之前都更新一下。

[qojnbbqtg]

哦 谢了 我待会试下。。。