Can someone explain how to set the focus to a component

Question

Hello,
What is the best way to ensure that a component gets the focus with code. I have tried requestFocus and requestFocusInWindow and none of them seems to do there work. The frame containing the components that should get the focus is displayed, the component is focusable so that is not the problem. What I found out is that if the component is deep in a nesting of panes (where the top pane is in the frame) is that calling requestFocus or requestFocusInWindow does not give the component where this focus is called on the focus but either the pane that contains it, one of the parent panes of this pane or one of the components in these panes, in almost all cases the component requesting the focus does not get the focus at all. I always have to write a work around in defining a focus listener for all these panes that transfer the focus back to the component that requested the focus originally, I can't believe that this is the way to ensure that a component has the focus via code. I have searched for documentation but found nothing on what requestFocus(inWindow) is actually dooing (a lot about focus traversibility but I don't want to control this, just make sure that a component gets the focus).
Again I'm pretty sure that the toplevel window is activated and that the component that requested the focus is focusable (I had created a derived version of the DefaultFocusManager that showed who has focus). Personally I think (and I'm not alone if you do a search in this forum on focus management) that there is either a big problem in the documentation of focus management or that it is still not possible to even try to set the focus on a component in a easy way.
Marc

Answer 1

Hello,
thanks for your reply, here is some example code that illustrates the problem I have (the actual code is to big to show here, which is the raison why I did not posted it here). The code wil create a frame with a JPanel with a JTextField, a 'New' Jbutton and a 'Delete' Jbutton, a tabbed pane in the center ('New' will create a new JPanel, add it to the tabbed pane and set the focus on it, either by calling RequestFocusInWindow() directly or by calling it via InvokeLater (someone on this forum suggested to use this). I changed also the focusmanager to show the component that has the focus when you type something. To test compile and run the program (either with a call to requesteFocusInWindow directly or indirectly (by changing the comments), on my system I get the following behaviour:
1. requestFocusInWindow called directly
Start program en type, the tabbed pane has the focus
Press New and type something, a button has the focus not the created panel
Press New again and type something, a button has the focus not the created panel
2. requestFocusInWindow be called indirectly
Start program and type, the tabbed pane has the focus
Press New and type, the created panel has the focus (I thought at one moment that I had found the solution there, but alas ...)
Press New again and type something, a button has again the focus.
Note that with my real program it is not always a button that will have the focus, sometimes it is a combobox or a TextField (I tried to get this with the example code (the JTextField) but did not succeed.
Hopes this clarify the problem a little bid, what I want is when the window is visible to set focus on newly created panes (or in the real program on the panel that is selected via the tabbed pane or via a key combination to shift the focus between the panels) but requestFocusInWindow seems to behave unpredicatable. I can't imagine that what I see is a bug so I must make some assumptions which are not valid but I don't see them, btw listening on the WindowListener is I think not the solution because the frame is already displayed when I want to set the focus and I do not use a modal dialog box.
The example code follows here
Marc
* Main.java
* Created on December 21, 2004, 8:58 AM
package testfocus;
import javax.swing.*;
import java.awt.*;
import java.awt.event.*;
* @author marc
public class Main
static int counter;
/** Creates a new instance of Main */
public Main()
* @param args the command line arguments
public static void main(String[] args)
JFrame frm=new JFrame();
JPanel content=new JPanel();
frm.setContentPane(content);
final JTabbedPane paneContainer=new JTabbedPane();
JPanel bar=new JPanel();
JButton create=new JButton(new AbstractAction("New")
public void actionPerformed(ActionEvent ev)
counter++;
final JPanel pnl=new JPanel();
pnl.setName("test"+counter);
paneContainer.add(pnl);
pnl.setFocusable(true);
pnl.requestFocusInWindow();
/* Either use this or the previous line
SwingUtilities.invokeLater(new Runnable()
public void run()
pnl.requestFocusInWindow();
JButton delete=new JButton(new AbstractAction("Delete")
public void actionPerformed(ActionEvent ev)
int i=paneContainer.getComponentCount()-1;
if (i>=0)
paneContainer.remove(i);
JTextField dummy=new JTextField("Test");
bar.add(dummy);
bar.add(create);
bar.add(delete);
content.setLayout(new BorderLayout());
content.add(bar,BorderLayout.SOUTH);
content.add(paneContainer,BorderLayout.CENTER);
frm.setSize(300,400);
FocusManager.setCurrentManager(new DefaultFocusManager()
public void processKeyEvent(Component component,KeyEvent ev)
System.out.println("Focus owner"+getFocusOwner());
super.processKeyEvent(component,ev);
frm.setVisible(true);
}