java - 如何排列Java GUI按钮？

Question

我需要按特定顺序排列按钮，但无论我做什么修改，它只会改变按钮的大小，而不改变位置。抱歉，如果这是一个简单的问题，这是我的第一个 Java 类，我无法理解如何安排内容和事件处理。

public class SwingCalculator extends JFrame {
    private JButton jbtReset;
    private JButton jbtAdd;
    private JButton jbtSubtract;

    private double TEMP;
    private double SolveTEMP;
    private JTextField jtfResult;

    Boolean addBool = false;
    Boolean subBool = false;

    String display = "";

    public SwingCalculator() 
    {
        JPanel p1 = new JPanel();
        p1.setLayout(new GridLayout(4, 3));
        p1.add(jbtReset = new JButton("Reset"));

        JPanel p2 = new JPanel();
        p2.setLayout(new FlowLayout());
        p2.add(jtfResult = new JTextField(10));
        jtfResult.setEditable(true);

        JPanel p3 = new JPanel();
        p3.setLayout(new GridLayout(5, 1));
        p3.add(jbtAdd = new JButton("+"));
        p3.add(jbtSubtract = new JButton("-"));

        JPanel p = new JPanel();
        p.setLayout(new GridLayout());
        p.add(p2);
        p.add(p1);
        p.add(p3);

        add(p);

        jbtAdd.addActionListener(new ListenToAdd());
        jbtSubtract.addActionListener(new ListenToSubtract());
        jbtReset.addActionListener(new ListenToReset());
    } //JavaCaluclator()

    class ListenToReset implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            //display = jtfResult.getText();
            jtfResult.setText("");
            addBool = false;
            subBool = false;
            TEMP = 0;
            SolveTEMP = 0;
        }
    }

    class ListenToAdd implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            TEMP = Double.parseDouble(jtfResult.getText());
            jtfResult.setText("");
            addBool = true;
            SolveTEMP = SolveTEMP + TEMP;
            jtfResult.setText(  Double.toString(SolveTEMP));
            addBool = false;
            subBool = false;
        }
    }

    class ListenToSubtract implements ActionListener {
        public void actionPerformed(ActionEvent e) {
            TEMP = Double.parseDouble(jtfResult.getText());
            jtfResult.setText("");
            subBool = true;
            SolveTEMP = SolveTEMP - TEMP;
            jtfResult.setText(  Double.toString(SolveTEMP));
            addBool = false;
            subBool = false;
        }
    }

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        SwingCalculator calc = new SwingCalculator();
        calc.pack();
        calc.setLocationRelativeTo(null);
        calc.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        calc.setVisible(true);
    }

} //JavaCalculator

我的结果:

预期结果:

Answer 1

您可以将 GridBagLayout 与各种选项一起使用。

例如:

GridBagLayout grid = new GridBagLayout();  
GridBagConstraints gbc = new GridBagConstraints();  
setLayout(grid); 
//add TF
gbc.gridx=1;
gbc.gridy=0;
this.add(new JTextField(10),gbc);
gbc.gridx=0;
gbc.gridy=1;
this.add(new JButton("+"),gbc);
gbc.gridx=1;
this.add(new JButton("-"),gbc);
gbc.gridx=2;
this.add(new JButton("Reset"),gbc);

//also for another display (first TF will be on the same x as - Button) 
//(and maybe you want TF to cover the space for all 3 Button +,-,Reset)
//you could add 2 panels one over other (x=0 : y=0,y=1), place TF on P1 and all Buttons on P2