java - 将 Tablecellrenderer 应用于列

Question

尝试将 tablecellrenderer 应用于列。我需要三个不同的图标，分别用于文件夹、zip\rar 文件等。

我该如何设置它们？

If 子句(if f.isDirectory()) 根本不起作用。

public class FirstCellRenderer extends DefaultTableCellRenderer {
    @Override
    public Component getTableCellRendererComponent(JTable table, Object value, boolean isSelected,
            boolean hasFocus, int row, int column) {
        JLabel label = (JLabel) super.getTableCellRendererComponent(table, value, isSelected,
                hasFocus, row, column);
        File f = (File) value;
        ImageIcon folderIcon = new ImageIcon(getClass().getResource("/images/folder.png"));
        ImageIcon archiveIcon = new ImageIcon(getClass().getResource("/images/archive.png"));

        if (!isSelected) {
            label.setBackground(row % 2 == 0 ? Color.LIGHT_GRAY : Color.WHITE);
        }

        label.setIcon(f.isDirectory() ? folderIcon : archiveIcon);
        label.setText(f.getName());

        return label;
    }
}

Answer 1

可能有多种原因导致您没有得到预期的结果，但您为我们诊断问题提供的信息太少，因此这一切都只是猜测。

您可能-忘记向表注册渲染器，或者使用错误的类型或列注册它
您可能-没有将图像放在正确的位置
您可能-您的文件列表中没有目录。

下面是一个简单的示例，它演示了渲染器的核心概念正在工作，肯定还缺少其他东西......

import java.awt.Color;
import java.awt.Component;
import java.awt.EventQueue;
import java.io.File;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;

public class TestTable100 {

    public static void main(String[] args) {
        new TestTable100();
    }

    public TestTable100() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                DefaultTableModel model = new DefaultTableModel();
                model.addColumn("Files");
                for (File file : new File(System.getProperty("user.home")).listFiles()) {
                    model.addRow(new Object[]{file});
                }

                JTable table = new JTable(model);
                table.getColumnModel().getColumn(0).setCellRenderer(new FirstCellRenderer());

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new JScrollPane(table));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public class FirstCellRenderer extends DefaultTableCellRenderer {

        @Override
        public Component getTableCellRendererComponent(JTable table, Object value,
                        boolean isSelected, boolean hasFocus, int row, int column) {
            JLabel label = (JLabel) super.getTableCellRendererComponent(table,
                            value, isSelected, hasFocus, row, column);
            File f = (File) value;
//            ImageIcon folderIcon = new ImageIcon(getClass().getResource(
//                            "/images/folder.png"));
//            ImageIcon archiveIcon = new ImageIcon(getClass().getResource(
//                            "/images/archive.png"));

            if (!isSelected) {
                label.setBackground(row % 2 == 0 ? Color.LIGHT_GRAY : Color.WHITE);
            }

//            label.setIcon(f.isDirectory() ? folderIcon : archiveIcon);
            String prefix = f.isDirectory() ? "[d]" : "[f]";
            label.setText(prefix + " " + f.getName());

            return label;
        }
    }
}

更新为以不同方式显示 Zip 文件

请注意，File API 不能很好地处理某些“特殊”文件，例如符号链接(symbolic link)或 Windows 等效文件(我看着你，我的音乐)

import java.awt.Color;
import java.awt.Component;
import java.awt.EventQueue;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.ImageIcon;
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.JScrollPane;
import javax.swing.JTable;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.DefaultTableCellRenderer;
import javax.swing.table.DefaultTableModel;

public class TestTable100 {

    public static void main(String[] args) {
        new TestTable100();
    }

    public TestTable100() {
        EventQueue.invokeLater(new Runnable() {
            @Override
            public void run() {
                try {
                    UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
                } catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException ex) {
                    ex.printStackTrace();
                }

                DefaultTableModel model = new DefaultTableModel();
                model.addColumn("Files");
                for (File file : new File(System.getProperty("user.home")).listFiles()) {
                    model.addRow(new Object[]{file});
                }

                JTable table = new JTable(model);
                table.getColumnModel().getColumn(0).setCellRenderer(new FirstCellRenderer());

                JFrame frame = new JFrame("Testing");
                frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
                frame.add(new JScrollPane(table));
                frame.pack();
                frame.setLocationRelativeTo(null);
                frame.setVisible(true);
            }
        });
    }

    public static class FirstCellRenderer extends DefaultTableCellRenderer {

        protected static ImageIcon FOLDER_ICON;
        protected static ImageIcon FILE_ICON;
        protected static ImageIcon ZIP_FILE_ICON;

        static {
            try {
                FOLDER_ICON = new ImageIcon(ImageIO.read(FirstCellRenderer.class.getResource("/Folder.png")));
            } catch (IOException exp) {
                FOLDER_ICON = null;
                exp.printStackTrace();
            }
            try {
                FILE_ICON = new ImageIcon(ImageIO.read(FirstCellRenderer.class.getResource("/File.png")));
            } catch (IOException exp) {
                FILE_ICON = null;
                exp.printStackTrace();
            }
            try {
                ZIP_FILE_ICON = new ImageIcon(ImageIO.read(FirstCellRenderer.class.getResource("/ZipFile.png")));
            } catch (IOException exp) {
                ZIP_FILE_ICON = null;
                exp.printStackTrace();
            }
        }

        @Override
        public Component getTableCellRendererComponent(JTable table, Object value,
                boolean isSelected, boolean hasFocus, int row, int column) {
            super.getTableCellRendererComponent(table, value, isSelected, hasFocus, row, column);
            File f = (File) value;
            setIcon(null);
            if (f.isDirectory()) {
                setIcon(FOLDER_ICON);
            } else {
                String name = f.getName();
                if (name.toLowerCase().endsWith(".zip")) {
                    setIcon(ZIP_FILE_ICON);
                } else {
                    setIcon(FILE_ICON);
                }
            }
            setText(f.getName());

            return this;
        }
    }
}