java - GridBagLayout 不接受我的 rowspan 命令(gridtheight)

Question

我即将学习 Java。我正在尝试为带有 GridBagLayout 的简单计算器编写 GUI。

问题是我的“+”按钮没有超过 2 行高。我不知道为什么？我试着在最后一行做一次:

    c.gridwidth = 1;
    c.gridy = 4;
    c.gridx = 3;
    c.gridheight = 2;
    c.ipady = 26;
    subpanel.add(bplus, c);

还有一次在 2. 最后一行。

    c.gridwidth = 1;
    c.gridy = 3;
    c.gridx = 3;
    c.gridheight = 2;
    c.ipady = 26;
    subpanel.add(bplus, c);

这里是gui的打洞代码，如果要测试的话，可能要调main了。

package gui;

import classes.Rechner;

import javax.swing.*;
import java.awt.*;
import java.awt.event.ActionEvent;
import java.awt.event.ActionListener;
import java.awt.event.KeyEvent;
import java.awt.event.KeyListener;

/**
 * Created by tq67 on 17.07.2014.
 */
public class CalculatorGUI extends JFrame {

public static void main(String[] args) {

    CalculatorGUI gui = new CalculatorGUI();
    gui.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    gui.setVisible(true);


}

    public CalculatorGUI() {
        setTitle("Calculator");
        setBounds(300, 300, 220, 225);

        JPanel subpanel = new JPanel();
        JPanel headpanel = new JPanel();
        final JTextField input = new JTextField();

        input.addKeyListener(new KeyListener() {
            @Override
            public void keyTyped(KeyEvent e) {

            }

            @Override
            public void keyPressed(KeyEvent e) {

            }

            @Override
            public void keyReleased(KeyEvent e) {
                if (10 == e.getKeyCode()) {
                    Rechner rechner = new Rechner(input.getText());
                    input.setText(rechner.rechnen().toPlainString());
                }
                if (27 == e.getKeyCode()) {
                    input.setText("");
                }
            }
        });
        ActionListener buttonListener = new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                input.setText(input.getText() + e.getActionCommand());
            }
        };
        ActionListener resultListener = new ActionListener() {
            @Override
            public void actionPerformed(ActionEvent e) {
                if (e.getActionCommand().equals("=")) {
                    Rechner rechner = new Rechner(input.getText());
                    input.setText(rechner.rechnen().toPlainString());
                } else {
                    input.setText("");
                }

            }

            private void calc() {
                Rechner rechner = new Rechner(input.getText());
                input.setText(rechner.rechnen().toPlainString());
            }
        };

        JButton b1 = new JButton("1");
        JButton b2 = new JButton("2");
        JButton b3 = new JButton("3");
        JButton b4 = new JButton("4");
        JButton b5 = new JButton("5");
        JButton b6 = new JButton("6");
        JButton b7 = new JButton("7");
        JButton b8 = new JButton("8");
        JButton b9 = new JButton("9");
        JButton b0 = new JButton("0");

        JButton bdot = new JButton(".");
        JButton bplus = new JButton("+");
        JButton bminus = new JButton("-");
        JButton bdiv = new JButton("/");
        JButton bmult = new JButton("*");
        JButton bresult = new JButton("=");

        JButton bcancel = new JButton("C");
        b1.addActionListener(buttonListener);
        b2.addActionListener(buttonListener);
        b3.addActionListener(buttonListener);
        b4.addActionListener(buttonListener);
        b5.addActionListener(buttonListener);
        b6.addActionListener(buttonListener);
        b7.addActionListener(buttonListener);
        b8.addActionListener(buttonListener);
        b9.addActionListener(buttonListener);
        b0.addActionListener(buttonListener);
        bdot.addActionListener(buttonListener);
        bplus.addActionListener(buttonListener);
        bminus.addActionListener(buttonListener);
        bdiv.addActionListener(buttonListener);
        bmult.addActionListener(buttonListener);

        bresult.addActionListener(resultListener);
        bcancel.addActionListener(resultListener);

        headpanel.setLayout(new GridBagLayout());
        subpanel.setLayout(new GridBagLayout());
        GridBagConstraints c = new GridBagConstraints();




        c.fill = GridBagConstraints.HORIZONTAL;
        c.weightx = 1;
        c.weighty = 3;
        c.gridx = 0;
        c.gridy = 0;
        c.ipady = 10;
        headpanel.add(input, c);

        setLayout(new BorderLayout());
        add(headpanel, BorderLayout.NORTH);
        add(subpanel, BorderLayout.SOUTH);
        c.fill = GridBagConstraints.HORIZONTAL;
        c.ipady = 0;
        c.gridx = 0;
        c.gridy = 0;
        subpanel.add(b7, c);
        c.gridx++;
        subpanel.add(b8, c);
        c.gridx++;
        subpanel.add(b9, c);
        c.gridx++;
        subpanel.add(bmult, c);

        c.fill = GridBagConstraints.HORIZONTAL;
        c.gridx = 0;
        c.gridy = 1;
        subpanel.add(b4, c);
        c.gridx++;
        subpanel.add(b5, c);
        c.gridx++;
        subpanel.add(b6, c);
        c.gridx++;
        subpanel.add(bdiv, c);


        c.fill = GridBagConstraints.HORIZONTAL;
        c.gridx = 0;
        c.gridy = 2;
        subpanel.add(b1, c);
        c.gridx++;
        subpanel.add(b2, c);
        c.gridx++;
        subpanel.add(b3, c);
        c.gridx++;
        subpanel.add(bminus, c);


        c.fill = GridBagConstraints.HORIZONTAL;
        c.gridheight = 1;
        c.ipady = 0;
        c.gridx = 0;
        c.gridy = 3;
        subpanel.add(bdot, c);
        c.gridwidth = 2;
        c.gridx++;
        subpanel.add(b0, c);
        c.gridwidth = 1;
        c.gridx = 3;
        c.gridheight = 2;
        c.ipady = 26;
        subpanel.add(bplus, c);


        c.fill = GridBagConstraints.HORIZONTAL;
        c.gridwidth = 1;
        c.ipady = 0;
        c.gridx = 0;
        c.gridy = 4;
        subpanel.add(bcancel, c);
        c.gridx = 1;
        c.gridwidth = 2;
        subpanel.add(bresult, c);

    }
}

我在 Stackoverflow 中读到一个错误，当您使用 gridx 大于 0 时，您将遇到 gridheight 问题...

目前 GUI 看起来像这样:

感谢您的帮助。

Answer 1

有两件事，首先，在使用后重置gridheight

c.gridwidth = 1;
c.gridx = 3;
c.gridheight = 2;
c.ipady = 26;
subpanel.add(bplus, c);

c.fill = GridBagConstraints.HORIZONTAL;
c.gridwidth = 1;
c.ipady = 0;
c.gridx = 0;
c.gridy = 4;
// Still using the gridheight of 2...
subpanel.add(bcancel, c);

应该更像是……

c.fill = GridBagConstraints.HORIZONTAL;
c.gridwidth = 1;
c.ipady = 0;
c.gridx = 0;
c.gridy = 4;
c.gridheight = 1;
subpanel.add(bcancel, c);

我也会去掉 c.ipady = 26;，但那是我 ;)

其次，利用BOTH 填充约束...

c.fill = GridBagConstraints.BOTH;
c.gridwidth = 1;
c.gridx = 3;
c.gridheight = 2;
c.ipady = 26;
subpanel.add(bplus, c);

还有...

public void keyReleased(KeyEvent e) {
    if (10 == e.getKeyCode()) {
        Rechner rechner = new Rechner(input.getText());
        input.setText(rechner.rechnen().toPlainString());
    }
    if (27 == e.getKeyCode()) {
        input.setText("");
    }
}

keyCode 不代表 ASCII 字符，而是代表虚拟键码。您应该使用 KeyEvent.VK_ENTER(我认为)和 KeyEvent.VK_ESCAPE。请注意，JTextField 已经有能力处理 ActionListener 接口(interface)的 Enter。无论如何，您应该考虑使用 Key Bindings可能的话API