JFileChooser 中的单列垂直滚动

Question

如何强制我的 JFileChooser 具有垂直滚动的单列而不是水平滚动的多列？

Answer 1

如果我理解您的要求，您或许可以使用 JList#setLayoutOrientation(JList.VERTICAL):

import java.awt.*;
import java.awt.event.*;
import java.util.*;
import java.util.stream.Stream;
import javax.swing.*;

public class FileChooserLayoutOrientationTest {
  private Component makeUI() {
    JTextArea log = new JTextArea();

    JButton button1 = new JButton("Default");
    button1.addActionListener(e -> {
      JFileChooser chooser = new JFileChooser();
      int retvalue = chooser.showOpenDialog(log.getRootPane());
      if (retvalue == JFileChooser.APPROVE_OPTION) {
        log.setText(chooser.getSelectedFile().getAbsolutePath());
      }
    });

    JButton button2 = new JButton("LayoutOrientation: VERTICAL");
    button2.addActionListener(e -> {
      JFileChooser chooser = new JFileChooser();
      stream(chooser)
        .filter(JList.class::isInstance)
        .map(JList.class::cast)
        .findFirst()
        .ifPresent(FileChooserLayoutOrientationTest::addHierarchyListener);
      int retvalue = chooser.showOpenDialog(log.getRootPane());
      if (retvalue == JFileChooser.APPROVE_OPTION) {
        log.setText(chooser.getSelectedFile().getAbsolutePath());
      }
    });

    JPanel p = new JPanel();
    p.setBorder(BorderFactory.createTitledBorder("JFileChooser"));
    p.add(button1);
    p.add(button2);

    JPanel pp = new JPanel(new BorderLayout());
    pp.add(p, BorderLayout.NORTH);
    pp.add(new JScrollPane(log));
    return pp;
  }

  // @see https://github.com/aterai/java-swing-tips/blob/master/GetComponentsRecursively/src/java/example/MainPanel.java
  public static Stream<Component> stream(Container parent) {
    return Arrays.stream(parent.getComponents())
      .filter(Container.class::isInstance)
      .map(c -> stream(Container.class.cast(c)))
      .reduce(Stream.of(parent), Stream::concat);
  }
  private static void addHierarchyListener(JList<?> list) {
    list.addHierarchyListener(new HierarchyListener() {
      @Override public void hierarchyChanged(HierarchyEvent e) {
        if ((e.getChangeFlags() & HierarchyEvent.SHOWING_CHANGED) != 0
            && e.getComponent().isShowing()) {
          list.putClientProperty("List.isFileList", Boolean.FALSE);
          list.setLayoutOrientation(JList.VERTICAL);
        }
      }
    });
  }
  public static void main(String[] args) {
    EventQueue.invokeLater(() -> {
      JFrame f = new JFrame();
      f.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
      f.getContentPane().add(new FileChooserLayoutOrientationTest().makeUI());
      f.setSize(320, 240);
      f.setLocationRelativeTo(null);
      f.setVisible(true);
    });
  }
}

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