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class MyMouseListener extends MouseAdapter{
private int step; //决定Button上的标号每次增加的步长
public MyMouseListener(int step){this.step=step;}
public void mousePressed(MouseEvent evt){
EventObject e = (EventObject)evt; //显示无法Cast的错误,但是MouseEvent明明就是EventObject的子类?
Button button=(Button)evt.getSource(); //显示evt没有getSource这个方法,该方法不是从EventObject继承的嘛?
int count=Integer.parseInt(button.getLabel());
button.setLabel(new Integer(step+count).toString()); //把Button上的标号加step
}
}
package MyEvent;
import java.awt.event.*;
import java.awt.*;
import java.util.EventObject;
public class AdapterCounter extends Frame{
private Button button=new Button("1");
public AdapterCounter(String title){
super(title);
//把MyMouseListener的实例注册为Button的监听器
button.addMouseListener(new MyMouseListener(2));
add(button);
setSize(100,100);
setVisible(true);
this.addWindowListener(new WindowAdapter(){
public void windowClosing(WindowEvent e){
System.exit(0);
}
});
}
public static void main(String args[]){
new AdapterCounter("hello");
}
}
class MyMouseListener extends MouseAdapter{
private int step; //决定Button上的标号每次增加的步长
public MyMouseListener(int step){this.step=step;}
public void mousePressed(MouseEvent e){
EventObject evt = (EventObject)e;
Button button=(Button)evt.getSource();
int count=Integer.parseInt(button.getLabel());
button.setLabel(new Integer(step+count).toString()); //把Button上的标号加step
}
}