问题
I want to recreate a table header looks using JLabel. The look and feel of the JLabel needs to be exactly like the JTableHeader would be, specified by the system.
This is what I have tried so far:
JLabel header = new JLabel("Title");
header.setOpaque(true);
header.setBackground(UIManager.getColor(new JTableHeader().getBackground()));
header.setBorder(UIManager.getBorder(new JTableHeader().getBorder()));
But, the UIManager returns null for the color and border.
Any ideas?
This is how I set the Look and Feel:
javax.swing.UIManager.setLookAndFeel(javax.swing.UIManager.getSystemLookAndFeelClassName());
回答1:
There are more issues involved then just getting the color and border of the table header. Each cell/column is rendered by a TableCellRenderer meaning that the values return by the UIManager may be ignored...
For example, the following renders the JTableHeader and applies border/background to a JLabel based on values returned by the UIManager under the Window's Look and Feel...
As you can see, there's quite a difference between them
How ever, if all you're interested in is display a "group header" of some kind over the top of another component on a scroll pane, you could simply add a JTableHeader to the scroll panes column view directly...
public class TestHeader {
public static void main(String[] args) {
new TestHeader();
}
public TestHeader() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException ex) {
} catch (InstantiationException ex) {
} catch (IllegalAccessException ex) {
} catch (UnsupportedLookAndFeelException ex) {
}
TableColumnModel model = new DefaultTableColumnModel();
final TableColumn column = new TableColumn(0, 250);
column.setHeaderValue("Test");
model.addColumn(column);
JTableHeader header = new JTableHeader();
header.setColumnModel(model);
final JTextArea textArea = new JTextArea();
JScrollPane scrollPane = new JScrollPane(textArea);
scrollPane.setColumnHeaderView(header);
textArea.addComponentListener(new ComponentAdapter() {
@Override
public void componentResized(ComponentEvent e) {
column.setWidth(textArea.getWidth());
}
});
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(scrollPane);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}
UPDATED
public class TestHeader {
public static void main(String[] args) {
new TestHeader();
}
public TestHeader() {
EventQueue.invokeLater(new Runnable() {
@Override
public void run() {
try {
UIManager.setLookAndFeel(UIManager.getSystemLookAndFeelClassName());
} catch (ClassNotFoundException ex) {
} catch (InstantiationException ex) {
} catch (IllegalAccessException ex) {
} catch (UnsupportedLookAndFeelException ex) {
}
TableColumnModel model = new DefaultTableColumnModel();
final TableColumn column = new TableColumn(0, 250);
column.setHeaderValue("I don't see the problem");
model.addColumn(column);
final JTableHeader header = new JTableHeader();
header.setColumnModel(model);
DefaultTableModel tm = new DefaultTableModel(new Object[]{"A", "B", "C"}, 0);
tm.addRow(new Object[]{"1", "2", "3", "4"});
tm.addRow(new Object[]{"5", "6", "7", "8"});
tm.addRow(new Object[]{"9", "10", "11", "12"});
tm.addRow(new Object[]{"13", "14", "15", "16"});
final JTable table = new JTable(tm);
final JScrollPane scrollPane = new JScrollPane(table);
/**
* For some reason, the header isn't being applied as soon as the
* table is added to the scroll pane, so we need to jump our next
* request to the end of the of event queue so that it will
* occur some time in the future
*/
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
scrollPane.setColumnHeaderView(header);
}
});
table.addComponentListener(new ComponentAdapter() {
@Override
public void componentResized(ComponentEvent e) {
column.setWidth(table.getWidth());
}
});
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
frame.setLayout(new BorderLayout());
frame.add(scrollPane);
frame.pack();
frame.setLocationRelativeTo(null);
frame.setVisible(true);
}
});
}
}
回答2:
Try taking the defaults from UIManager:
Color color = UIManager.getColor("TableHeader.background");
Border border = UIManager.getBorder("TableHeader.CellBorder");
回答3:
You need to set a look and feel for the application before trying:
header.setBackground(UIManager.getColor(new JTableHeader().getBackground()));
header.setBorder(UIManager.getBorder(new JTableHeader().getBorder()));
you should set a look and feel first like so:
try {
for (LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (Exception e) {
// If Nimbus is not available, you can set the GUI to another look and feel.
}
Here is an example:
import javax.swing.JFrame;
import javax.swing.JLabel;
import javax.swing.SwingUtilities;
import javax.swing.UIManager;
import javax.swing.UnsupportedLookAndFeelException;
import javax.swing.table.JTableHeader;
public class Test {
public Test() {
initComponents();
}
public static void main(String[] args) {
SwingUtilities.invokeLater(new Runnable() {
@Override
public void run() {
try {
//set nimbus look and feel
for (UIManager.LookAndFeelInfo info : UIManager.getInstalledLookAndFeels()) {
if ("Nimbus".equals(info.getName())) {
UIManager.setLookAndFeel(info.getClassName());
break;
}
}
} catch (ClassNotFoundException | InstantiationException | IllegalAccessException | UnsupportedLookAndFeelException e) {
e.printStackTrace();
}
new Test();
}
});
}
private void initComponents() {
JFrame frame = new JFrame();
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JLabel header = new JLabel("Title");
header.setBackground(UIManager.getColor(new JTableHeader().getBackground()));
header.setBorder(UIManager.getBorder(new JTableHeader().getBorder()));
frame.add(header);
frame.pack();
frame.setVisible(true);
}
}
回答4:
I figured I'll create a JTable without any rows and place a JTextPane right underneath.
And it works like charm.
JTextPane textPane = new JTextPane();
JPanel panel = new JPanel(new BorderLayout());
JTable table = new JTable(0, 1);
table.setPreferredScrollableViewportSize(new Dimension(600, 0));
JScrollPane js = new JScrollPane(table)
panel.add(js, BorderLayout.NORTH);
panel.add(new JScrollPane(textPane),BorderLayout.CENTER);
来源：https://stackoverflow.com/questions/13213838/how-can-i-set-a-jlabels-background-and-border-the-same-as-a-table-header