为什么ButtonListener不能工作？

Question

所以我试图在我的代码中理解侦听器的概念，我得到了错误：

The type eventHandle.ButtonListener must implement the inherited abstract method ActionListener.actionPerformed(ActionEvent)

为什么会发生这种情况？

package test;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
public class eventHandle extends JApplet{
    private JButton onebutton;
    private JButton twobutton;
    private JLabel label; 
    private int flax;
    private JPanel panel;

    public void init(){
        flax = 0;
        onebutton = new JButton("click to add 1");
        onebutton.addActionListener(new ButtonListener());
        twobutton = new JButton("click to add 2");
        twobutton.addActionListener(new ButtonListener());
        label = new JLabel("count: " + flax);

        panel = new JPanel();
        panel.setLayout(new GridLayout(1,2));
        panel.add(onebutton);
        panel.add(twobutton);

        Container contain = getContentPane();
        contain.setLayout(new GridLayout(2,1));
        contain.add(label);
        contain.add(panel);

        setSize(400,300);

    }
    public class ButtonListener implements ActionListener{

        public void actionPerformed(Action event){
            if (event == onebutton){
                flax += 1;
            }
            if (event == twobutton){
                flax += 2;
            }
            label.setText("count: " + flax);
        }

    }
}

Answer 1

您没有很好地覆盖ActionListener接口，您必须这样做

public void actionPerformed(ActionEvent event){

而不是

public void actionPerformed(Action event){

Answer 2

使用ActionEvent代替Action，并使用event.getSource()比较JButton对象。

public void actionPerformed(ActionEvent event){
   if (event.getSource() == onebutton){
      flax += 1;
   }
   if (event.getSource() == twobutton){
     flax += 2;
   }
   label.setText("count: " + flax);
}

更多https://docs.oracle.com/javase/tutorial/uiswing/events/actionlistener.html