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我对在东面板上设置的文本字段和组合框组件有疑问。出于某种原因，当我添加 Box 布局以按 Y 排列它们时，上面列出的一些组件并没有像它们应该的那样与按钮正确对齐和缩放大小。

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.FlowLayout;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JTable;
import javax.swing.JTextField;

/**
 *
 * @author Isaac
 */
public class Test2 extends JFrame {

    private JButton addNewColumnButton;
    private JButton calculateColumnButton;
    private JButton resultButton;

    private JLabel textLabel;

    private JTextField columnField;
    private JTextField resultField;            

    private JComboBox columnListCB;
    private JTable table;

    private String[] tableCols = {"Fisrt Column", "Second Column", "Third Column", "", "", "", "", ""};
    private Object[][] tableRows = {
            {true, null, null, null, null, null, null, null},
            {true, null, null, null, null, null, null, null},
            {true, null, null, null, null, null, null, null},
            {true, null, null, null, null, null, null, null},
            {true, null, null, null, null, null, null, null},
            {true, null, null, null, null, null, null, null},
            {true, null, null, null, null, null, null, null},
            {true, null, null, null, null, null, null, null}
    };

    public Test2() {
        this.setSize(new Dimension(600, 280)); 
        this.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        this.setLocationRelativeTo(null);
        this.setResizable(false);

        this.init();
        this.add(getUIPanel());

        this.pack();
        this.setVisible(true);
    }

    private JPanel getUIPanel() {
        JPanel panel = new JPanel(new BorderLayout());
        panel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
        panel.setBackground(Color.blue);

        JPanel center = new JPanel();
        center.add(table);

        JPanel eastPanel = new JPanel();
        eastPanel.setBackground(Color.MAGENTA);
            Box eastPanelBox = Box.createVerticalBox();
            eastPanelBox.add(addNewColumnButton);
            eastPanelBox.add(Box.createVerticalStrut(14));
            eastPanelBox.add(columnField);
            eastPanelBox.add(Box.createVerticalStrut(5));
            eastPanelBox.add(columnListCB);
            eastPanelBox.add(Box.createVerticalStrut(5));
            eastPanelBox.add(calculateColumnButton);
        eastPanel.add(eastPanelBox);

        JPanel southPanel = new JPanel(new FlowLayout(FlowLayout.LEFT, 5, 5));
        southPanel.setBackground(Color.green);
            southPanel.add(resultButton);
            southPanel.add(textLabel);
            southPanel.add(resultField);

        panel.add(center, BorderLayout.WEST);
        panel.add(southPanel, BorderLayout.SOUTH);
        panel.add(eastPanel, BorderLayout.EAST); 
        return panel;
    }

    private void init() {
        final int COMPONENT_WIDTH = 130;
        final int COMPONENT_HEIGHT = 25;

        table = new JTable(tableRows, tableCols);

        addNewColumnButton = new JButton("New Column");
        addNewColumnButton.setPreferredSize(new Dimension(COMPONENT_WIDTH, COMPONENT_HEIGHT));

        columnField = new JTextField();
        columnField.setPreferredSize(new Dimension(COMPONENT_WIDTH, COMPONENT_HEIGHT));

        columnListCB = new JComboBox(tableCols);
        columnListCB.setPreferredSize(new Dimension(COMPONENT_WIDTH, COMPONENT_HEIGHT));

        calculateColumnButton = new JButton("Calculate Column");
        calculateColumnButton.setPreferredSize(new Dimension(COMPONENT_WIDTH, COMPONENT_HEIGHT));

        resultButton = new JButton("Calculate");
        calculateColumnButton.setPreferredSize(new Dimension(COMPONENT_WIDTH, COMPONENT_HEIGHT));

        textLabel = new JLabel("Result:");

        resultField = new JTextField(); 
        resultField.setPreferredSize(new Dimension(COMPONENT_WIDTH / 2, COMPONENT_HEIGHT));
    }

    public static void main(String[] args) {
        new Test2();
    }
}
4

1 回答 1

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您的示例中出现了几个问题：

  • “一般来说，由上到下BoxLayout对象控制的所有组件都应该具有相同的 X 对齐方式。”

  • JTextField使用适当的构造函数指定 a 的初始大小。

  • setPreferredSize()当你真的想要覆盖时不要使用getPreferredSize()。

  • 调用pack()然后设置位置和可见性。

  • 正确使用初始线程。

  • 不要不必要地扩展顶级组件，例如JFrame.

  • 在不可调整大小的容器上避免这个陷阱。

图片

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.Dimension;
import java.awt.EventQueue;
import java.awt.FlowLayout;
import java.awt.GridLayout;
import javax.swing.BorderFactory;
import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JComboBox;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.JTextField;

/**
 * @author Isaac
 * @see https://stackoverflow.com/a/18037704/230513
 */
public class Test2 {

    private JButton addNewColumnButton;
    private JButton calculateColumnButton;
    private JButton resultButton;
    private JLabel textLabel;
    private JTextField columnField;
    private JTextField resultField;
    private JComboBox columnListCB;
    private JTable table;
    private String[] tableCols = {
        "Fisrt Column", "Second Column", "Third Column"
    };
    private Object[][] tableRows = {
        {true, null, null, null, null, null, null, null},
        {true, null, null, null, null, null, null, null},
        {true, null, null, null, null, null, null, null},
        {true, null, null, null, null, null, null, null},
        {true, null, null, null, null, null, null, null},
        {true, null, null, null, null, null, null, null},
        {true, null, null, null, null, null, null, null},
        {true, null, null, null, null, null, null, null}
    };

    public Test2() {
        JFrame f = new JFrame("Test2");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(getUIPanel());
        f.pack();
        f.setLocationRelativeTo(null);
        f.setVisible(true);
    }

    private JPanel getUIPanel() {
        JPanel panel = new JPanel(new BorderLayout());
        panel.setBorder(BorderFactory.createEmptyBorder(5, 5, 5, 5));
        panel.setBackground(Color.blue);

        JPanel center = new JPanel(new GridLayout());
        table = new JTable(tableRows, tableCols);
        table.setPreferredScrollableViewportSize(new Dimension(240, 120));
        center.add(new JScrollPane(table));

        JPanel eastPanel = new JPanel();
        eastPanel.setBackground(Color.MAGENTA);
        Box eastPanelBox = Box.createVerticalBox();
        addNewColumnButton = new JButton("New Column");
        addNewColumnButton.setAlignmentX(Box.CENTER_ALIGNMENT);
        eastPanelBox.add(addNewColumnButton);
        eastPanelBox.add(Box.createVerticalStrut(14));
        columnField = new JTextField();
        columnField.setAlignmentX(Box.CENTER_ALIGNMENT);
        eastPanelBox.add(columnField);
        eastPanelBox.add(Box.createVerticalStrut(5));
        columnListCB = new JComboBox(tableCols);
        columnListCB.setAlignmentX(Box.CENTER_ALIGNMENT);
        eastPanelBox.add(columnListCB);
        eastPanelBox.add(Box.createVerticalStrut(5));
        calculateColumnButton = new JButton("Calculate Column");
        calculateColumnButton.setAlignmentX(Box.CENTER_ALIGNMENT);
        eastPanelBox.add(calculateColumnButton);
        eastPanel.add(eastPanelBox);

        JPanel southPanel = new JPanel(new FlowLayout(FlowLayout.LEFT, 5, 5));
        southPanel.setBackground(Color.green);
        resultButton = new JButton("Calculate");
        southPanel.add(resultButton);
        textLabel = new JLabel("Result:");
        southPanel.add(textLabel);
        resultField = new JTextField(10);
        southPanel.add(resultField);

        panel.add(center, BorderLayout.WEST);
        panel.add(southPanel, BorderLayout.SOUTH);
        panel.add(eastPanel, BorderLayout.EAST);
        return panel;
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                new Test2();
            }
        });
    }
}
于 2013-08-03T21:57:57.020 回答