Question

我创建了一个JList，其中包含目录中的文件列表。这是JList。

JList MList;
String ListData[]
// Create a new listbox control
List = new JList(ListData);

我还创建了一个方法来读取目录中的文本文件列表：

     public String ReadDirectory() {
        String path = "C://Documents and Settings/myfileTxt";

        String files = null;
        File folder = new File(path);
        File[] listOfFiles = folder.listFiles();

        for (int i = 0; i < listOfFiles.length; i++) {
            if (listOfFiles[i].isFile()) {
                files = listOfFiles[i].getName();
                if (files.endsWith(".txt") || files.endsWith(".TXT")) {
                    System.out.println(files);
                }
            }
        }
        return files;
    }

问题是我想要JList中此方法的结果（文本文件列表）。如何将File对象放入JList？

Answer 1

不要将字符串放入JList，使用File个对象并设置渲染器。由于默认渲染器返回的组件是JLabel，因此可以轻松设置图标。

File List

import java.awt.*;
import javax.swing.*;
import javax.swing.border.EmptyBorder;
import javax.swing.border.Border;
import javax.swing.filechooser.FileSystemView;
import java.io.File;
import java.io.FileFilter;

/**
This code uses a JList in two forms (layout orientation vertical & horizontal wrap) to
display a File[].  The renderer displays the file icon obtained from FileSystemView.
*/
class FileList {

    public Component getGui(File[] all, boolean vertical) {
        // put File objects in the list..
        JList fileList = new JList(all);
        // ..then use a renderer
        fileList.setCellRenderer(new FileRenderer(!vertical));

        if (!vertical) {
            fileList.setLayoutOrientation(javax.swing.JList.HORIZONTAL_WRAP);
            fileList.setVisibleRowCount(-1);
        } else {
            fileList.setVisibleRowCount(9);
        }
        return new JScrollPane(fileList);
    }

    public static void main(String[] args) {
        SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                File f = new File(System.getProperty("user.home"));
                FileList fl = new FileList();
                Component c1 = fl.getGui(f.listFiles(new TextFileFilter()),true);

                //f = new File(System.getProperty("user.home"));
                Component c2 = fl.getGui(f.listFiles(new TextFileFilter()),false);

                JFrame frame = new JFrame("File List");
                JPanel gui = new JPanel(new BorderLayout());
                gui.add(c1,BorderLayout.WEST);
                gui.add(c2,BorderLayout.CENTER);
                c2.setPreferredSize(new Dimension(375,100));
                gui.setBorder(new EmptyBorder(3,3,3,3));

                frame.setContentPane(gui);
                frame.pack();
                frame.setLocationByPlatform(true);
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.setVisible(true);
            }
        });
    }
}

class TextFileFilter implements FileFilter {

    public boolean accept(File file) {
        // implement the logic to select files here..
        String name = file.getName().toLowerCase();
        //return name.endsWith(".java") || name.endsWith(".class");
        return name.length()<20;
    }
}

class FileRenderer extends DefaultListCellRenderer {

    private boolean pad;
    private Border padBorder = new EmptyBorder(3,3,3,3);

    FileRenderer(boolean pad) {
        this.pad = pad;
    }

    @Override
    public Component getListCellRendererComponent(
        JList list,
        Object value,
        int index,
        boolean isSelected,
        boolean cellHasFocus) {

        Component c = super.getListCellRendererComponent(
            list,value,index,isSelected,cellHasFocus);
        JLabel l = (JLabel)c;
        File f = (File)value;
        l.setText(f.getName());
        l.setIcon(FileSystemView.getFileSystemView().getSystemIcon(f));
        if (pad) {
            l.setBorder(padBorder);
        }

        return l;
    }
}

Answer 2

@Andrew Thompson

晚上03:36在我的TimeZone和06:00我必须醒来，

但在某个地方，我失去了（不是我）JLabel，天哪，它可能是

import java.awt.*;
import java.io.File;
import javax.swing.*;
import javax.swing.filechooser.FileSystemView;

public class FilesInTheJList {

    public FilesInTheJList() {
        JList displayList = new JList(new File("C:\\").listFiles());
        displayList.setSelectionMode(javax.swing.ListSelectionModel.SINGLE_SELECTION);
        displayList.setCellRenderer(new MyCellRenderer());
        displayList.setLayoutOrientation(javax.swing.JList.HORIZONTAL_WRAP);
        displayList.setName("displayList");
        JFrame f = new JFrame("Files In the JList");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.setPreferredSize(new Dimension(500, 300));
        displayList.setVisibleRowCount(-1);
        f.add(new JScrollPane(displayList));
        f.pack();
        f.setVisible(true);
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                FilesInTheJList fITJL = new FilesInTheJList();
            }
        });
    }

    private static class MyCellRenderer extends DefaultListCellRenderer  {

        private static final long serialVersionUID = 1L;

        @Override
        public Component getListCellRendererComponent(JList list, Object value,
                int index, boolean isSelected, boolean cellHasFocus) {
            if (value instanceof File) {
                File file = (File) value;
                setText(file.getName());
                setIcon(FileSystemView.getFileSystemView().getSystemIcon(file));
                if (isSelected) {
                    setBackground(list.getSelectionBackground());
                    setForeground(list.getSelectionForeground());
                } else {
                    setBackground(list.getBackground());
                    setForeground(list.getForeground());
                }
                setEnabled(list.isEnabled());
                setFont(list.getFont());
                setOpaque(true);
            }
            return this;
        }
    }
}

enter image description here

import java.awt.*;
import java.io.File;
import javax.swing.*;
import javax.swing.filechooser.FileSystemView;

public class FilesInTheJList {

    private static final int COLUMNS = 4;
    private Dimension size;

    public FilesInTheJList() {
        final JList list = new JList(new File("C:\\").listFiles()) {

            private static final long serialVersionUID = 1L;

            @Override
            public Dimension getPreferredScrollableViewportSize() {
                if (size != null) {
                    return new Dimension(size);
                }
                return super.getPreferredScrollableViewportSize();
            }
        };
        list.setFixedCellHeight(50);
        list.setFixedCellWidth(150);
        size = list.getPreferredScrollableViewportSize();
        size.width *= COLUMNS;
        list.setSelectionMode(javax.swing.ListSelectionModel.SINGLE_SELECTION);
        list.setCellRenderer(new MyCellRenderer());
        list.setVisibleRowCount(0);
        list.setLayoutOrientation(JList.HORIZONTAL_WRAP);

        JFrame f = new JFrame("Files In the JList");
        f.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        f.add(new JScrollPane(list));
        f.pack();
        f.setVisible(true);
    }

    public static void main(String[] args) {
        EventQueue.invokeLater(new Runnable() {

            @Override
            public void run() {
                FilesInTheJList fITJL = new FilesInTheJList();
            }
        });
    }

    private static class MyCellRenderer extends JLabel implements ListCellRenderer {

        private static final long serialVersionUID = 1L;

        @Override
        public Component getListCellRendererComponent(JList list, Object value,
                int index, boolean isSelected, boolean cellHasFocus) {
            if (value instanceof File) {
                File file = (File) value;
                setText(file.getName());
                setIcon(FileSystemView.getFileSystemView().getSystemIcon(file));
                if (isSelected) {
                    setBackground(list.getSelectionBackground());
                    setForeground(list.getSelectionForeground());
                } else {
                    setBackground(list.getBackground());
                    setForeground(list.getForeground());
                }
                setPreferredSize(new Dimension(250, 25));
                setEnabled(list.isEnabled());
                setFont(list.getFont());
                setOpaque(true);
            }
            return this;
        }
    }
}

Answer 3

我不太明白你在做什么 - 看起来你想要将JList的内容过滤为只有.txt扩展名的文件。在这种情况下，您可能希望实现FilenameFilter，这将导致list()返回String[]中仅与您指定的文件名匹配的文件名列表。

例如，

public String[] ReadDirectory() {
    String path = "C://Documents and Settings/myfileTxt";

    String files = null;
    File folder = new File(path);
    FilenameFilter txtFilter = new TextFileFilter();
    String[] listOfFiles = folder.listFiles(txtFilter);

    return listOfFiles;
}



public class TextFileFilter extends FilenameFilter
{
    public boolean accept(File dir, String name)
    {
        if(name != null && name.endsWith(".txt"))
        {
            return true;
        }

        return false;
    }
}

Answer 4

创建字符串List<String> fnames = new ArrayList<String>();列表，用文件名（fnames.add(files);）填充，然后使用list.setListData(fnames.toArray());将其设置为JList。我想这应该有用。

Answer 5

只需像这样编辑你的代码，

public ArrayList<String> ReadDirectory() {
        String path = "C://Documents and Settings/myfileTxt";

        ArrayList<String> files = new ArrayList<String>();
        File folder = new File(path);
        File[] listOfFiles = folder.listFiles();

        for (int i = 0; i < listOfFiles.length; i++) {
            if (listOfFiles[i].isFile()) {
                files.add(listOfFiles[i].getName());
                if (files.endsWith(".txt") || files.endsWith(".TXT")) {
                    System.out.println(files);
                }
            }
        }
        return files;
    }

将返回ArrayList对象，然后您可以将该ArrayList对象转换为普通数组。

像这样的东西，让我们说你的变量名是，

ArrayList<String> listData = new ArrayList<String>();

只需将其转换为普通数组，

listData.toArray();

包含目录中文件列表的JList

5 个答案: