(完整word版)Java知识总结完整版,推荐文档

add(num1);add(lblPlus);add(num2);add(btnEqual);add(num3); pack();

setVisible(true); }

private class MyMonitor implements ActionListener { public void actionPerformed(ActionEvent e) { int n1 = Integer.parseInt(num1.getText()); int n2 = Integer.parseInt(num2.getText()); num3.setText(\ } } }

Graphics类

每个Component都有一个paint(Graphics g)用于实现绘图目的，每次重画该Component时都自动调用paint方法

Graphics类中提供了许多绘图方法，如：

drawRect(int x,int y,int width,int height)

fillRoundRect(int x,int y,int width,int height,int arcWidth,int arcHeight)等

Adapter&repaint import java.awt.*;

import java.awt.event.*; import java.util.*;

public class MyMouseAdapter{

public static void main(String args[]) { new MyFrame(\ } }

class MyFrame extends Frame { ArrayList points = null; MyFrame(String s) { super(s);

points = new ArrayList(); setLayout(null);

setBounds(300,300,400,300);

this.setBackground(new Color(204,204,255)); setVisible(true);

this.addMouseListener(new Monitor()); }

public void paint(Graphics g) { Iterator i = points.iterator(); while(i.hasNext()){

Point p = (Point)i.next(); g.setColor(Color.BLUE); g.fillOval(p.x,p.y,10,10); } }

public void addPoint(Point p){ points.add(p); } }

class Monitor extends MouseAdapter {

public void mousePressed(MouseEvent e) { MyFrame f = (MyFrame)e.getSource();

f.addPoint(new Point(e.getX(),e.getY())); f.repaint(); } }

鼠标事件适配器

抽象类java.awt.event.MouseAdapter实现了MouseListener接口，可以使用其子类作为MouseEvent的监听器，只要重写其相应的方法即可 对于其他的监听器，也有对应的适配器

使用适配器可以避免监听器类定义没有必要的空方法 repaint-update()-paint()