具有固定高度和可变宽度的 JButton 布局

Question

我寻找一个具有固定高度的 JButtons 的 LayoutManager，JButtons 在宽度上扩展以适应其容器的大小。在 JButtons 上方应该有一个 JLabel 本身，在“选择文件：”的行上。这旨在作为 JFileChooser 的附件，让用户选择最近的文件。我无法让它看起来很正确，我尝试过使用多个 JPanel 和 LayoutManager，例如 BoxLayout。使用 BoxLayout 时，JButtons 仅扩展至必须包含其文本的范围；但我希望所有 JButton 的宽度都相同，这样它们看起来就不好笑了。

注意：我还使用了其他 LayoutManager，例如 Border 和 GridLayout，但它们大多忽略了我的尺寸设置，并且看起来不够复杂。我必须手动完成，Netbeans 等不是一个选项。

工作示例，但视觉上不正确

import java.awt.Color;
import java.awt.GridLayout;

import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JPanel;


public class Chooser extends JPanel {


    public Chooser(){
        this.setLayout(new GridLayout(0,1));

        JPanel labelPanel = new JPanel();
        JLabel label = new JLabel("Choose a file:");
        labelPanel.add(label);
        labelPanel.setBackground(Color.red);

        JPanel buttonPanel = new JPanel();
        buttonPanel.add(new JButton("long pathname to a file goes here"));
        buttonPanel.setBackground(Color.blue);

        this.add(labelPanel);
        this.add(buttonPanel);
    }


    /**
     * @param args
     */
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        Chooser c = new Chooser();
        JFileChooser fileChooser = new JFileChooser();
        fileChooser.setAccessory(c);
        fileChooser.showOpenDialog(null);
    }

}

Answer 1

如果 GridLayout 嵌套在 BorderLayout 中（实际上是在 JScrollPane 中）呢？

import java.awt.BorderLayout;
import java.awt.Color;
import java.awt.GridLayout;

import javax.swing.Box;
import javax.swing.JButton;
import javax.swing.JFileChooser;
import javax.swing.JLabel;
import javax.swing.JPanel;
import javax.swing.JScrollPane;

public class Chooser extends JPanel {
   private static final String[] BUTTON_TEXTS = { "Hello", "Goodbye",
         "Hello Goodbye", "Adios", "This is a long String for WTF" };

   public Chooser() {
      this.setLayout(new BorderLayout());

      JPanel labelPanel = new JPanel();
      JLabel label = new JLabel("Choose a file:");
      labelPanel.add(label);
      labelPanel.setBackground(Color.red);

      JPanel buttonPanel = new JPanel(new GridLayout(0, 1));
      for (int i = 0; i < BUTTON_TEXTS.length; i++) {
         buttonPanel.add(new JButton(BUTTON_TEXTS[i]));
      }
      buttonPanel.add(Box.createVerticalGlue()); // to pad the bottom if needed
      buttonPanel.setBackground(Color.blue);

      this.add(labelPanel, BorderLayout.PAGE_START);
      this.add(new JScrollPane(buttonPanel), BorderLayout.CENTER);
   }

   public static void main(String[] args) {
      Chooser c = new Chooser();
      JFileChooser fileChooser = new JFileChooser();
      fileChooser.setAccessory(c);
      fileChooser.showOpenDialog(null);
   }

}

示例 2 有一个简单的 JList，将其选择放在文件选择器中：

import java.awt.*;
import java.io.File;

import javax.swing.*;
import javax.swing.event.ListSelectionEvent;
import javax.swing.event.ListSelectionListener;

public class Chooser extends JPanel {
   private static final String[] BUTTON_TEXTS = { "Hello", "Goodbye",
         "Hello Goodbye", "Adios", "This is a long String for WTF", "Hello",
         "Goodbye", "Hello Goodbye", "Adios", "This is a long String for WTF" };

   public Chooser(final JFileChooser fileChooser) {
      setLayout(new BorderLayout());

      JPanel labelPanel = new JPanel();
      JLabel label = new JLabel("Choose a file:");
      labelPanel.add(label);
      labelPanel.setBackground(Color.red);

      final JList list = new JList(BUTTON_TEXTS);
      list.addListSelectionListener(new ListSelectionListener() {
         public void valueChanged(ListSelectionEvent e) {
            String selectedString = list.getSelectedValue().toString();
            fileChooser.setSelectedFile(new File(selectedString));
         }
      });

      add(labelPanel, BorderLayout.PAGE_START);
      add(new JScrollPane(list), BorderLayout.CENTER);
   }

   public static void main(String[] args) {
      JFileChooser fileChooser = new JFileChooser();
      Chooser c = new Chooser(fileChooser);
      fileChooser.setAccessory(c);
      fileChooser.showOpenDialog(null);
   }

}