java - Java GUI 中单选按钮的对齐方式

Question

这是我的程序的样子:

但我似乎无法让我的单选按钮和 JLabel 正确对齐。如何将单选按钮右侧对齐并堆叠？另外，如何让 JLabel 和 JTextField 显示堆叠？这是我的代码:

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

public class SeriesCalc extends JFrame {

private final int WIDTH = 300;
private final int HEIGHT = 300;
private JFrame frame = new JFrame("Recursion");
private JPanel panel = new JPanel();
private JPanel labels = new JPanel();
private JPanel buttons = new JPanel();
private JPanel radioButtonsPanel = new JPanel();
private JLabel inputLabel = new JLabel("Enter i:");
private JLabel resultLabel = new JLabel("Result:");
private JTextField inputField = new JTextField(15);
private JTextField resultField = new JTextField(15);
private JButton compute = new JButton("Compute");
private JRadioButton iterative, recursive;

public SeriesCalc() {
    frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    radioButtonsPanel.add(iterative = new JRadioButton("Iterative"));
    radioButtonsPanel.add(recursive = new JRadioButton("Recursive"));
    add(radioButtonsPanel);
    ButtonGroup radioButtons = new ButtonGroup();
    radioButtons.add(iterative);
    radioButtons.add(recursive);

    iterative.addActionListener(new Calculations());
    recursive.addActionListener(new Calculations());
    compute.addActionListener(new Calculations());

    resultField.setEditable(false);

    panel.setLayout(new GridLayout(4, 1));
    labels.add(inputLabel);
    labels.add(inputField);
    labels.add(resultLabel);
    labels.add(resultField);
    buttons.add(compute);
    panel.add(radioButtonsPanel);
    panel.add(labels);
    panel.add(buttons);
    frame.getContentPane().add(panel);
}

public void display() {
    frame.setSize(WIDTH, HEIGHT);
    frame.setVisible(true);
}

public class Calculations implements ActionListener {

    public void actionPerformed(ActionEvent e) {
        Object calc = e.getSource();
        try {
            if (calc == compute) {
                if (iterative.isSelected()) {
                    double n = Double.parseDouble(inputField.getText());
                    double product = 1;
                    for (int i = 3; i < n; i++) {
                        product *= i;
                    }
                    resultField.setText(Double.toString(product));
                } else if (recursive.isSelected()) {
                    double i = Double.parseDouble(inputField.getText());
                    double y = 0;
                    if (i == 1) {
                resultField.setText(Double.toString(i / (2. * i +     1)));
                    } else {
             resultField.setText(Double.toString(i / (2. * i + 1)+ (i -1)));
                    }
                }
            }
        } catch (NumberFormatException nfe) {
            System.err.println(nfe.getMessage());
        }
    }
}

public static void main(String[] args) {
    SeriesCalc calculator = new SeriesCalc();
    calculator.display();
}
}

Answer 1

我在您的程序中看到一些错误:

1. 您正在扩展 JFrame 并在同一程序中创建它的实例。使用其中之一(我推荐后者)，请参阅Using extends vs calling it inside of class .

2. 您正在设置 frame.setSize()，虽然这不是错误，但最好在程序中调用 frame.pack()。它将遵循所有组件在其 preferredSize 中显示的最小尺寸。如果您需要窗口的精确大小，请重写 getPreferredSize() 方法。

3. 您没有将程序放在 Event Dispatch Thread (EDT) 上，这可能会在将来导致线程问题，因为 Swing 不是线程安全的，这可以通过以下方式解决:

   public static void main(String[] args) {
       SwingUtilities.invokeLater(new Runnable() {
           @Override
           public void run() {
               //Call your constructor here
           }
       });
   }
   

<小时/>

but I can't seem to get my radio buttons and my JLabel to be aligned properly

这是因为 JPanel 的默认布局管理器是 FlowLayout，因此它将您的组件放置在一行中。

我的想法是使用一个带有 0 行(它将根据需要添加任意数量)和 2 列的 GridLayout 来实现您想要的 GUI，并且在您需要“空白”空间的地方可以添加空的JLabel。

我没有在代码中放置 ActionListener，因为这个问题是关于 GUI 设计而不是其中的逻辑。

我想我没有遗漏任何东西，这是以下代码创建的输出:

import java.awt.GridLayout;

import javax.swing.ButtonGroup;
import javax.swing.JButton;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JRadioButton;
import javax.swing.JTextField;
import javax.swing.SwingUtilities;

public class SeriesCalc {

    private JFrame frame;

    private JRadioButton iterative;
    private JRadioButton recursive;
    private ButtonGroup group;

    private JLabel label;
    private JLabel resultLabel;

    private JTextField field;
    private JTextField resultField;

    private JButton computeButton;

    private JPanel pane;

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            @Override
            public void run() {
                new SeriesCalc().createAndShowGui();
            }
        });
    }

    public void createAndShowGui() {
        frame = new JFrame(getClass().getSimpleName());

        pane = new JPanel();
        pane.setLayout(new GridLayout(0, 2, 2, 5));

        iterative = new JRadioButton("Iterative");
        recursive = new JRadioButton("Recursive");

        group = new ButtonGroup();

        group.add(iterative);
        group.add(recursive);

        computeButton = new JButton("Compute");

        label = new JLabel("Enter \"i\": ");
        resultLabel = new JLabel("Result: ");

        field = new JTextField(5);
        resultField = new JTextField(5);
        resultField.setEnabled(false);

        pane.add(new JLabel(""));
        pane.add(iterative);

        pane.add(new JLabel(""));
        pane.add(recursive);

        pane.add(label);
        pane.add(field);

        pane.add(new JLabel(""));
        pane.add(computeButton);

        pane.add(resultLabel);
        pane.add(resultField);

        frame.add(pane);
        frame.pack();
        frame.setVisible(true);
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
    }
}