java - JButton 数组 Action 监听器仅适用于最后一个按钮

Question

我制作了一个按钮数组，并尝试在 for 循环中向每个按钮添加一个 ActionListener，并使用 for 循环监听所有按钮，但问题是唯一响应的按钮是最后创建的按钮。我做错了什么？

nums = new JButton[13];
ListenForButton lfb = new ListenForButton();
for (int i = 1; i < 13; i++) {
    nums[i].addActionListener(lfb);
}

<小时/>

private class ListenForButton implements ActionListener{
    public void actionPerformed(ActionEvent e) {
        for(int i=0;i<13;i++){
            if( e.getSource() == nums[i]) {
                System.out.println("pressed");
            }
        }
    }
}

Answer 1

方法 ActionEvent.getSource() 返回一个 Object 类型的实例，为此您需要将其类型转换为 JButton

if( e.getSource() == nums[i])

说实话，所以这样做而不是上面的语句:

if( ((JButton)e.getSource()) == nums[i])

也试试这个:

nums = new JButton[13];

for (int i = 0; i < 13; i++) 
 {
    nums[i] = new JButton();
    nums[i].addActionListener(new ActionListener() {
       public void actionPerformed(ActionEvent ae)
       {
           System.out.println("pressed");
       }
    });
 }

或者使用 ActionCommand，如下所示:

nums = new JButton[13];

ListenerForButton lfb = new ListenerForButton();
for (int i = 0; i < 13; i++) 
 {
    nums[i] = new JButton();
    nums[i].setActionCommand("button"+i);
    nums[i].addActionListener(lfb);
 }

 private class ListenForButton implements ActionListener{

    public void actionPerformed(ActionEvent e) {

        for(int i=0;i<13;i++){

        if( e.getActionCommand().equals("button"+i)) {
               System.out.println("pressed" + i); //for  getting which button is actually clicked
           }
    }