无法在actionevent Buttonclicked内添加到arraylist

Question

问题：我无法将单击按钮的值添加到ArrayList中。

示例：如果我单击名为E的按钮，那么我希望将E添加到arraylist中，之后如果我单击按钮S，那么它应该添加相同的arraylist。但这并不是在ArrayList中添加任何东西。它只显示当前单击的按钮

public class WordFinder extends JFrame implements ActionListener {
    private JButton buttons[];
    ArrayList<String> LettersClicked = new ArrayList<String>();
    private JTextArea jta;
    private JLabel jLabel;
    public WordFinder(){

        int numberOfLetters = 64;
        buttons = new JButton[numberOfLetters];

        JFrame frame = new JFrame("wordfinder");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setBackground(Color.red);
        JPanel mainPanel = new JPanel();
        mainPanel.setLayout(new BoxLayout(mainPanel, BoxLayout.Y_AXIS));

        JPanel topPanel = new JPanel();
        topPanel.setBorder(BorderFactory.createLineBorder(Color.GREEN));
        topPanel.setPreferredSize(new Dimension(600, 600));
        topPanel.setMaximumSize(new Dimension(600, 600));
        topPanel.setBackground(Color.red);

        JPanel bottomPanel = new JPanel();
        bottomPanel.setBorder(BorderFactory.createLineBorder(Color.yellow));
        bottomPanel.setPreferredSize(new Dimension(600, 300));
        bottomPanel.setMaximumSize(new Dimension(600, 300));
        bottomPanel.setBackground(Color.green);

        Font f3 = new Font(Font.DIALOG, Font.BOLD, 35);

        for (int i = 0;i<numberOfLetters;i++) {
            char letter = alphabet();
            buttons[i] = new JButton(String.valueOf(letter));
            buttons[i].setFont(f3);
           // buttons[i].setMinimumSize(new Dimension(40, 20));
            buttons[i].setPreferredSize(new Dimension(65, 65));
            buttons[i].setMargin(new Insets(0,0,0,0));
            buttons[i].setBackground(Color.white);
            buttons[i].setFocusPainted(false);
            buttons[i].addActionListener(this);
            topPanel.add(buttons[i]);
        }

        String buttValue = "";
        jLabel = new JLabel(""+buttValue);
        jLabel.setFont(f3);
        bottomPanel.add(jLabel);
        LettersClicked.add(jLabel.toString());

        for (int z = 0; z<LettersClicked.size(); z++){
            JLabel aa = new JLabel(""+LettersClicked.size());
            bottomPanel.add(aa);
        }

        mainPanel.add(topPanel);
        mainPanel.add(bottomPanel);

        frame.getContentPane().add(mainPanel);
        frame.setSize(1000,1000);
        frame.setMinimumSize(new Dimension(1000, 1000));
        frame.setVisible(true);
    }

    public char alphabet(){
        Random rnd = new Random();
        String alphabets = "ABCDEFGHIJKLMNOPQRSTUVWXYZ";
        char letter = alphabets.charAt(rnd.nextInt(alphabets.length()));
        return letter;
    }

    @Override
    public void actionPerformed(ActionEvent actionEvent) {
        JButton button = (JButton) actionEvent.getSource();
        jLabel.setText(button.getText());
        LettersClicked.add(button.getText());
    }
}

Answer 1

我认为您对GUI上显示的JLabel和ArrayList的内容感到困惑。问题实际上在前者。

当前的实现将替换JLabel的文本，而不是为每个按下的按钮追加文本。

因此，在actionperformed()方法中，更改这一行

jLabel.setText(button.getText());

jLabel.setText(jLabel.getText() + button.getText());