编程第九十六、九十七天天

Applet 类从 Container 类继承了许多事件处理方法。Container 类定义了几个方法，例如：processKeyEvent() 和processMouseEvent()，用来处理特别类型的事件，还有一个捕获所有事件的方法叫做 processEvent。

为了响应一个事件，Applet 必须重写合适的事件处理方法。

ExampleEventHandling.java 文件代码：

import java.awt.event.MouseListener;

import java.awt.event.MouseEvent;

import java.applet.Applet;

import java.awt.Graphics; 

public class ExampleEventHandling extends Applet implements MouseListener {

StringBuffer strBuffer;

public void init() {

addMouseListener(this);

strBuffer = new StringBuffer();

addItem("initializing the apple ");

}

public void start() {

addItem("starting the applet ");

}

public void stop() {

addItem("stopping the applet ");

}

public void destroy() {

addItem("unloading the applet");

}

void addItem(String word) {

System.out.println(word);

strBuffer.append(word);

repaint();

}

public void paint(Graphics g) {

//Draw a Rectangle around the applet's display area.

g.drawRect(0, 0,getWidth() - 1,getHeight() - 1);

//display the string inside the rectangle.

g.drawString(strBuffer.toString(), 10, 20);

}

public void mouseEntered(MouseEvent event) { }

public void mouseExited(MouseEvent event) { }

public void mousePressed(MouseEvent event) { }

public void mouseReleased(MouseEvent event) { }

public void mouseClicked(MouseEvent event) {

addItem("mouse clicked! ");

}

}