Question

我正在尝试创建一个创建9x9文本字段数组的程序，然后当按下某个按钮时，将打印包含数字的所有文本字段，并且所有空文本字段都会打印错误“text field”是空的”。但是，我收到一个错误，说变量必须是最终的。我假设这个程序假定数组“字段”尚未确定。

public static void initialize() {

        JFrame frame = new JFrame();
        frame.setSize(316, 400);
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        frame.getContentPane().setLayout(null);

        JButton btnNewButton = new JButton("New button");

        frame.getContentPane().add(btnNewButton);
        btnNewButton.setBounds(1, 320, 310, 35);

        int X;
        int Y;
        int XPosition = 21; // x location of textField
        int YPosition = 21; // y location of textField
        int[][] squares = new int[9][9];

        TextField[][] fields = new TextField[9][9];
        {
            for (Y = 0; Y < 9; Y++) {
                XPosition = 0;
                for (X = 0; X <= 8; X++) {
                    fields[X][Y] = new TextField(1);
                    fields[X][Y].setColumns(1);
                    fields[X][Y].setBounds(XPosition, YPosition, 32, 32);
                    frame.getContentPane().add(fields[X][Y]);

                    XPosition = XPosition + 32;
                }
                YPosition = YPosition + 32;
            }
        }

        btnNewButton.addActionListener(new ActionListener() {

            public void actionPerformed(ActionEvent e) {

                if (fields[1][1].getText().isEmpty()) {

                    System.out.println(field[X][Y] + " is empty");

                } else {

                    for (int Y = 0; Y < 9; Y++) {
                        for (int X = 0; X <= 8; X++) {

                            System.out.println(fields[1][1].getText());
                            squares[X][Y] = Integer.parseInt((fields[X][Y].getText()));;

                        }
                    }
                }

            }
        });

    }

Answer 1

你可以通过使X和Y成为具有2个元素的最终数组来“修复”它。数组本身是最终的，但您可以随时更改其中的元素。

public static void initialize() {

    JFrame frame = new JFrame();
    frame.setSize(316, 400);
    frame.setVisible(true);
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    frame.getContentPane().setLayout(null);

    JButton btnNewButton = new JButton("New button");

    frame.getContentPane().add(btnNewButton);
    btnNewButton.setBounds(1, 320, 310, 35);

    final int fix[] = {0,0};
    fix[0] = 0;
    fix[1] = 0;
    int XPosition = 21; // x location of textField
    int YPosition = 21; // y location of textField
    int[][] squares = new int[9][9];

    TextField[][] fields = new TextField[9][9];
    {
        for (fix[1] = 0; fix[1] < 9; fix[1]++) {
            XPosition = 0;
            for (fix[0] = 0; fix[0] <= 8; fix[0]++) {
                fields[fix[0]][fix[1]] = new TextField(1);
                fields[fix[0]][fix[1]].setColumns(1);
                fields[fix[0]][fix[1]].setBounds(XPosition, YPosition, 32, 32);
                frame.getContentPane().add(fields[fix[0]][fix[1]]);

                XPosition = XPosition + 32;
            }
            YPosition = YPosition + 32;
        }
    }

    btnNewButton.addActionListener(new ActionListener() {

        public void actionPerformed(ActionEvent e) {

            if (fields[1][1].getText().isEmpty()) {

                System.out.println(fields[fix[0]][fix[1]] + " is empty");

            } else {

                for (int Y = 0; Y < 9; Y++) {
                    for (int X = 0; X <= 8; X++) {

                        System.out.println(fields[1][1].getText());
                        squares[X][Y] = Integer.parseInt((fields[X][Y].getText()));;

                    }
                }
            }

        }
    });

}

Java错误：从内部类引用的局部变量必须是最终的或有效的final

1 个答案: