突出显示JTable中带有图标的单元格

Question

I have a JTable with 3 columns in it. 1. Icon, 2. Name of file or folder, 3. File type or "Folder". I draw the Icon using a JLabel (I set background + png image) within the getTableCellRendererComponent method. Initially I draw an alternating background of the JLable either "white" or "grey" since those are the colors that the JTable Swing component alternates to draw the table. Now, when I select a row, the Icon (the first column) background does not get redrawn to "dark blue" same as the rest of the row.

Here are my questions:

General 1) How can also highlight the Icon cell when highlighting a row (pointers will suffice, no code expected)?

Specific

1.1) Do I have to use JLabel? Why can't I just eg .SetValueAt("image.png",0,0)

1.2) I tried the getColumnClass(...) but that seems to redraw ALL cells in a given column. Is that expected?

Thanks.

Answer 1

1.) The javax.swing.table.TableCellRenderer gets an isSelected parameter when it is called. You can easily write your own TableCellRenderer by inheriting from JLabel (for example) and overridding getTableCellRendererComponent : Adjust the Object and return this . Having your own renderer also allows you to set a breakpoint and really understand what is happening.

1.1 + 1.2.) Both setValueAt and getColumnClass are part if the model and will probably not solve your problem with the selected background.

You do not have to use JLabel : If you look at the return type from getTableCellRendererComponent you notice it is Component (not even JComponent ). I guess JLabel is just customary because it normally has all the features you want for the renderer and the DefaultTableCellRenderer also uses JLabel . For the most freedom I advise you to use JComponent and write your own paintComponent , but in this case you probably don't have to do that.

Answer 2

assuming the striping (alternate white/grey background) happens automatically in your LAF (Nimbus?), you shouldn't need a custom renderer: the table already has a default renderer registered for Icon and ImageIcon class. Make sure your tableModel returns one of those classes as columnClass for the first column and enjoy the automatics :-)

Here's a quick code snippet:

DefaultTableModel model = new DefaultTableModel(0, 2) {

    @Override
    public Class<?> getColumnClass(int columnIndex) {
        if (columnIndex == 0) {
            return Icon.class;
        }
        return super.getColumnClass(columnIndex);
    }

};
File[] files = new File(".").listFiles();
FileSystemView fsv = FileSystemView.getFileSystemView();
for (File f : files) {
    model.addRow(new Object[] {fsv.getSystemIcon(f), fsv.getSystemDisplayName(f)});
}
JTable table = new JTable(model);