关于使用awt和swing的布局

Question

因此，我尝试使用GridBagLayout创建基本的计算器布局，并在阅读了一些文档之后提出了以下建议：

import java.awt.*;
import javax.swing.*;

public class Test {
    public static void main(String args[]) {
        JFrame f = new JFrame("Calculator");
        f.setSize(1000, 550);
        f.setResizable(false);

        JPanel p1 = new JPanel();
        p1.setLayout(new GridBagLayout());
        GridBagConstraints c = new GridBagConstraints();

        JTextField out = new JTextField();
        out.setColumns(15);
        c.gridx = 0;
        c.gridy = 0;
        //c.gridwidth=4;
        p1.add(out, c);

        JButton b1 = new JButton("CLEAR");
        c.gridx = 0;
        c.gridy = 1;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b1, c);

        JButton b2 = new JButton("ERASE");
        c.gridx = 1;
        c.gridy = 1;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b2, c);

        JButton b3 = new JButton("ROOT");
        c.gridx = 2;
        c.gridy = 1;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b3, c);

        JButton b4 = new JButton("÷");
        c.gridx = 3;
        c.gridy = 1;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b4, c);

        JButton b5 = new JButton("7");
        c.gridx = 0;
        c.gridy = 2;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b5, c);

        JButton b6 = new JButton("8");
        c.gridx = 1;
        c.gridy = 2;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b6, c);

        JButton b7 = new JButton("9");
        c.gridx = 2;
        c.gridy = 2;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b7, c);

        JButton b8 = new JButton("X");
        c.gridx = 3;
        c.gridy = 2;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b8, c);

        JButton b9 = new JButton("4");
        c.gridx = 0;
        c.gridy = 3;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b9, c);

        JButton b10 = new JButton("5");
        c.gridx = 1;
        c.gridy = 3;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b10, c);

        JButton b11 = new JButton("6");
        c.gridx = 2;
        c.gridy = 3;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b11, c);

        JButton b12 = new JButton("+");
        c.gridx = 3;
        c.gridy = 3;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b12, c);

        JButton b13 = new JButton("1");
        c.gridx = 0;
        c.gridy = 4;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b13, c);

        JButton b14 = new JButton("2");
        c.gridx = 1;
        c.gridy = 4;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b14, c);

        JButton b15 = new JButton("3");
        c.gridx = 2;
        c.gridy = 4;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b15, c);

        JButton b16 = new JButton("-");
        c.gridx = 3;
        c.gridy = 4;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b16, c);

        JButton b17 = new JButton();
        c.gridx = 0;
        c.gridy = 5;
        c.fill = GridBagConstraints.HORIZONTAL;
        //c.fill = GridBagConstraints.VERTICAL;
        p1.add(b17, c);

        JButton b18 = new JButton("0");
        c.gridx = 1;
        c.gridy = 5;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b18, c);

        JButton b19 = new JButton();
        c.gridx = 2;
        c.gridy = 5;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b19, c);

        JButton b20 = new JButton("=");
        c.gridx = 3;
        c.gridy = 5;
        c.fill = GridBagConstraints.HORIZONTAL;
        p1.add(b20, c);


        f.add(p1);
        f.setVisible(true);
    }

}

结果是这样的：

因此，我取消注释此行以将JTextField扩展到末尾：

//c.gridwidth=4;

它做了这样奇怪的事情：

我不知道为什么只显示网格的一列。 是什么原因造成的？ 我该如何解决？ 我希望JTextField扩展到所有列。

Answer 1

我会尝试为每个按钮添加权重。

Answer 2

您需要重置下一个组件的gridwidth值，因为您正在重用相同的约束对象：

c.gridwidth=4;
p1.add(out,c);

JButton b1= new JButton("CLEAR");
c.gridx=0;
c.gridy=1;
c.gridwidth=1; // added
c.fill = GridBagConstraints.HORIZONTAL;
p1.add(b1,c);

现在，其余组件将使用1的gridwidth。