如何让我的 JButtone 更新面板？

Question

我目前正在使用一个程序来读取 txt 包括数独谜题，然后程序解决它并显示所有解决方案。 我几乎完成了，但遇到了一个问题。 我有一个下一个按钮，当单击时，它会更新按钮文本和更新/获取下一个解决方案（程序保存每个解决方案）。这是我的代码：

class Gui extends JFrame{
    int cnt = 1;
    String[][] solution;
    int nrRows, nrColumns;
    SudokuContainer sc;

    Gui(SudokuContainer sc, int nrRows, int nrColumns){
        this.sc = sc;
        this.nrRows = nrRows;
        this.nrColumns = nrColumns;
        createBoard(sc,nrRows,nrColumns);
        finnishingVows();
    }

    void finnishingVows(){
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        pack();
        setVisible(true);
    }

    void createBoard(SudokuContainer sc, int nrRows, int nrColumns) {
        JPanel panel = new JPanel();
        JLabel label;
        JButton previousButton;
        JButton nextButton;
        previousButton = new JButton("Previous (" + cnt + "/" + sc.nrSolutions + ")");
        nextButton = new JButton("Next (" + cnt + "/" + sc.nrSolutions + ")");
        solution = sc.get(cnt);
        nextButton.addActionListener(new Listener());
        panel.setLayout(new GridLayout(nrRows*nrColumns,nrRows*nrColumns));
        previousButton.addActionListener(new Listener2());

        for(int i = 0; i <solution.length;i++){
            for(int j = 0; j < solution[i].length; j++){
                String values = " "+solution[i][j]+" ";
                if(values.equals(" . ")) values = "";
                label = new JLabel(values);
                if((i+1)%2 != 0)
                     if(j == nrRows){
                         label.setBorder(BorderFactory.createMatteBorder(1, 1, 1, 1, Color.black)); //FIKSER PÅ STREKENE
                     }
                     else if(j == nrColumns){
                         label.setBorder(BorderFactory.createMatteBorder(1, 3, 1, 1, Color.black));//FIKSER PÅ STREKENE
                     }
                else
                    label.setBorder(BorderFactory.createMatteBorder(1, 1, 1, 1, Color.black));
                if((i+1)%2 == 0)
                    if(j == nrRows){
                        label.setBorder(BorderFactory.createMatteBorder(1, 1, 3, 1, Color.black));
                    }
                    else if(j == nrColumns){
                    label.setBorder(BorderFactory.createMatteBorder(1, 3, 3, 1, Color.black));
                    }
                else label.setBorder(BorderFactory.createMatteBorder(1, 1, 3, 1, Color.black));
                label.setFont(new Font("SansSerif", Font.BOLD, 32));
                panel.add(label);
            }
        }

        add(panel, BorderLayout.NORTH);
        add(nextButton, BorderLayout.EAST);
        add(previousButton, BorderLayout.WEST);
    }

    class Listener implements ActionListener{
        public void actionPerformed(ActionEvent e){
            cnt++;
            createBoard(sc,nrRows,nrColumns);
            finnishingVows();
        }
    }

    class Listener2 implements ActionListener{
        public void actionPerformed(ActionEvent e){
            cnt--;
            createBoard(sc,nrRows,nrColumns);
            finnishingVows();
        }
    }
} //class Gui slutt

Answer 1

正如其中一条评论中提到的，在添加更多组件之前，您不会删除组件。 如果您创建包含按钮和面板的类变量，您可以删除它们并添加新的。 这是我的看法：

class Gui extends JFrame{
    int cnt = 1;
    String[][] solution;
    int nrRows, nrColumns;
    SudokuContainer sc;
    private JPanel pan = null;
    private JButton nButton = null;
    private JButton pButton = null;

    Gui(SudokuContainer sc, int nrRows, int nrColumns){
        this.sc = sc;
        this.nrRows = nrRows;
        this.nrColumns = nrColumns;
        createBoard(sc,nrRows,nrColumns);
        finnishingVows();
    }

    void finnishingVows(){
        setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        pack();
        setVisible(true);
    }

    void createBoard(SudokuContainer sc, int nrRows, int nrColumns) {
        JPanel panel = new JPanel();
        JLabel label;
        JButton previousButton;
        JButton nextButton;
        previousButton = new JButton("Previous (" + cnt + "/" + sc.nrSolutions + ")");
        nextButton = new JButton("Next (" + cnt + "/" + sc.nrSolutions + ")");
        solution = sc.get(cnt);
        nextButton.addActionListener(new Listener());
        panel.setLayout(new GridLayout(nrRows*nrColumns,nrRows*nrColumns));
        previousButton.addActionListener(new Listener2());

        for(int i = 0; i <solution.length;i++){
            for(int j = 0; j < solution[i].length; j++){
                String values = " "+solution[i][j]+" ";
                if(values.equals(" . ")) values = "";
                label = new JLabel(values);
                if((i+1)%2 != 0)
                     if(j == nrRows){
                         label.setBorder(BorderFactory.createMatteBorder(1, 1, 1, 1, Color.black)); //FIKSER PÅ STREKENE
                     }
                     else if(j == nrColumns){
                         label.setBorder(BorderFactory.createMatteBorder(1, 3, 1, 1, Color.black));//FIKSER PÅ STREKENE
                     }
                else
                    label.setBorder(BorderFactory.createMatteBorder(1, 1, 1, 1, Color.black));
                if((i+1)%2 == 0)
                    if(j == nrRows){
                        label.setBorder(BorderFactory.createMatteBorder(1, 1, 3, 1, Color.black));
                    }
                    else if(j == nrColumns){
                    label.setBorder(BorderFactory.createMatteBorder(1, 3, 3, 1, Color.black));
                    }
                else label.setBorder(BorderFactory.createMatteBorder(1, 1, 3, 1, Color.black));
                label.setFont(new Font("SansSerif", Font.BOLD, 32));
                panel.add(label);
            }
        }

        if (pan != null) this.remove(pan);
        if (pButton != null) this.remove(pButton);
        if (nButton != null) this.remove(nButton);
        pan = panel;
        pButton = previousButton;
        nButton = nextButton;
        add(panel, BorderLayout.NORTH);
        add(nextButton, BorderLayout.EAST);
        add(previousButton, BorderLayout.WEST);
    }

    class Listener implements ActionListener{
        public void actionPerformed(ActionEvent e){
            cnt++;
            createBoard(sc,nrRows,nrColumns);
            finnishingVows();
        }
    }

    class Listener2 implements ActionListener{
        public void actionPerformed(ActionEvent e){
            cnt--;
            createBoard(sc,nrRows,nrColumns);
            finnishingVows();
        }
    }
}