java - 错误: local variable referenced from inner class must be final or effective final

Question

JButton[] button = new JButton[noOfDays];

for(int j=0 ;j<studentNameList.size() ;j++) {
    for(int i=0 ;i<button.length ;i++) {
        button[i]=new JButton((i+1)+"");
        attendencepanels.add(button[i]);

        button[i].addActionListener(new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
        ---->  button[i].setBackground(Color.red); //Local variable refenced from inner class must be final or effective final

                //JOptionPane.showMessageDialog(null, "test");
                }
            });

我如何解决actionPerformed方法中button[i]中的这个问题

Answer 1

虽然我不确定，但您也许可以从 ActionEvent e 参数获取 JButton 引用。看起来这就是 getSource() 返回的内容(事件最初发生的对象):

而不是

button[i].setBackground(Color.red);

尝试

JButton button = (JButton) e.getSource();
button.setBackground(Color.red);