求助 程序 错在哪里?怎么改
程序代码:
import java.awt.event.*; import java.awt.*; 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)); addWindowListener(new WindowAdapter(){ public void windowClosing(WindowEvent evt){ System.exit(0);//结束程序 } }); add(button); setSize(100,100); setVisible(true); } public static void main(String[] agrs){ 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 evt){ Button button=(Button)evt.getSource(); int count=Integer.parseInt(button.getLabel()); //把Button上的标号加step button.setLabel(new Integer(step+count).toString()); } }