java事件处理

Posted 2020-11-27 gjdftru

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。

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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! ");     } }