关于java事件驱动的问题

mmrx 2013-06-13 05:30:24

自己写了个小程序。如下：

import java.awt.*;

import java.awt.event.*;

import javax.swing.*;



public class MousePaint extends JFrame{

	

	private JButton redButton = new JButton("RED");

	private JButton blackButton = new JButton("BLACK");

	private JButton greenButton = new JButton("Green");

	private Graphics g;

	

	public MousePaint(){

		JPanel pCenter = new JPanel();

		JPanel pRight = new JPanel();

		

		pCenter.setLayout(new BorderLayout());

		pCenter.add(new MousePanel(),BorderLayout.CENTER);

		

		pRight.setLayout(new GridLayout(0,1));

		pRight.add( redButton);

		pRight.add( blackButton);

		pRight.add( greenButton);

		

		getContentPane().setLayout(new BorderLayout());

		getContentPane().add(pCenter,BorderLayout.CENTER);

		getContentPane().add(pRight,BorderLayout.EAST);

		

		buttonAdd();	

	}

	

	private void buttonAdd(){

		ButtonListener buttonListener = new ButtonListener();

		redButton.addActionListener(buttonListener);

		blackButton.addActionListener(buttonListener);

		greenButton.addActionListener(buttonListener);

		

	}

	

	class ButtonListener implements ActionListener{

		public void actionPerformed(ActionEvent e){

			if(e.getSource() == redButton ){

				g.setColor(Color.RED);

			}

			if(e.getSource() == blackButton ){

				g.setColor(Color.BLACK);

			}

			if(e.getSource() == greenButton ){

				g.setColor(Color.GREEN);

			}

		}

	}

	

	class MousePanel extends JPanel

		implements MouseListener,MouseMotionListener{

		

		final int CIRCLESIZE = 100;

		private Point lineStart = new Point(0,0);

		

		

		public MousePanel(){

			addMouseListener(this);

			addMouseMotionListener(this);

		}

		

		public void mouseClicked(MouseEvent e){

		}

		public void mouseEntered(MouseEvent e){

		}

		public void mouseExited(MouseEvent e){

		}

		public void mouseReleased(MouseEvent e){

		}

		public void mousePressed(MouseEvent e){

			lineStart.move(e.getX(),e.getY());

		}

		public void mouseDragged(MouseEvent e){

			g = getGraphics();

			

			if(e.isMetaDown()){//right button

				g.setColor(getBackground());

				g.fillOval(e.getX()-CIRCLESIZE/4, e.getY()-CIRCLESIZE/4, CIRCLESIZE/2, CIRCLESIZE/2);

			}

			else{

				g.setColor(Color.BLACK);

				g.drawLine(lineStart.x, lineStart.y, e.getX(), e.getY());

			}

			

			lineStart.move(e.getX(), e.getY());

			

			g.dispose();

		}

		public void mouseMoved(MouseEvent e){

		}

	}

	

	public static void main(String[] args){

		MousePaint frame = new MousePaint();

//		frame.pack();

		frame.setSize(400,400);

		frame.setTitle("MousePaint");

		frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);

		frame.setVisible(true);

	}



	}

我想用三个按钮来改变线条的颜色，弄了半天总是不行。应该是按钮和鼠标移动两块代码衔接不上，是不是那个Graphics变量g的问题？怎么样把二者联系起来?需要的效果是按那个按钮，线条变什么颜色，最好能有详细一些的说明，谢谢大神！
代码写的比较乱。。，顺便请教一下代码应该怎么布局

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mmrx 2013-06-13

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引用 6 楼 wuyanxue 的回复:

import java.awt.*;

import javax.swing.*;
import javax.swing.event.*;
import java.util.Random;

public class Test extends JPanel{
	
	Random r = new Random();
//重画的线程	
Thread t = new Thread(new Runnable() {
		public void run() {
			while(true) {
				repaint();
				try {
					Thread.sleep(100);	
				} catch(InterruptedException e) {
					
				}
				
			}
		}
		});
	//重写父类的paintComponent方法
	protected void paintComponent(Graphics g) {
		
		g.setColor(new Color(r.nextInt(100),r.nextInt(100),r.nextInt(100)));
		g.fillRect(10,10,400,400);
		
	}
	
	public static void main(String args[]) {
		Test t1 = new Test();
		JFrame f = new JFrame();
		f.setBounds(100,100,500,500);
		f.setVisible(true);	
		t1.setBounds(100,100,500,500);
		f.add(t1);
		t1.t.start();
		
	}
}

谢谢谢谢，代码很清晰易懂~~~我主要问的是按钮和画线的部分怎么连接

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总之要想解决你的问题就要学习线程推荐马士兵javaSE的视频楼主可以去这个网站去下载http://www.bjsxt.com/shipinxiazai/

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引用 3 楼 llr19931113 的回复:

[quote=引用 1 楼 u010300707 的回复:] 你没有把按钮和按钮的事件处理连接在一起，你button要添加一个ActionListiner。就是redButton.addActionListener(this).后面的mounseListener也是一样的连接。

我连接了呀，在方法buttonAdd（）里添加了监控器ButtonListener的[/quote] 哦我没看见如果还没学线程的话那么你的窗口就是静态的

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import java.awt.*;

import javax.swing.*;
import javax.swing.event.*;
import java.util.Random;

public class Test extends JPanel{
	
	Random r = new Random();
//重画的线程	
Thread t = new Thread(new Runnable() {
		public void run() {
			while(true) {
				repaint();
				try {
					Thread.sleep(100);	
				} catch(InterruptedException e) {
					
				}
				
			}
		}
		});
	//重写父类的paintComponent方法
	protected void paintComponent(Graphics g) {
		
		g.setColor(new Color(r.nextInt(100),r.nextInt(100),r.nextInt(100)));
		g.fillRect(10,10,400,400);
		
	}
	
	public static void main(String args[]) {
		Test t1 = new Test();
		JFrame f = new JFrame();
		f.setBounds(100,100,500,500);
		f.setVisible(true);	
		t1.setBounds(100,100,500,500);
		f.add(t1);
		t1.t.start();
		
	}
}

mmrx 2013-06-13

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引用 4 楼 wuyanxue 的回复:

Thread t = new Thread(new Runnable() {
		public void run() {
			while(true) {
				repaint();
				try {
					Thread.sleep(100);	
				} catch(InterruptedException e) {
					
				}
				
			}
		}
		});

您能把添加监听器的句子打一下么？没有看懂意思。。线程这块还没有自学到...

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Thread t = new Thread(new Runnable() {
		public void run() {
			while(true) {
				repaint();
				try {
					Thread.sleep(100);	
				} catch(InterruptedException e) {
					
				}
				
			}
		}
		});

mmrx 2013-06-13