Listening to focusedWindow property changes

Name: pzR10082 Date: 10/23/2000



My application creates 2 windows and adds a PropertyChangeListener
to KeyboardFocusManager to track focus transfers between them. When
i switch between windows, this listener is called two times. When it
is called for the first time, the new focusedWindow is reported to be
null. This should mean that the focused Window is not in the calling
application's context, which is not the case.

So currently an application has no way to distinguish between focus
transfers to another window created by this application and to a
foreign window.

Here's a test case:

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import java.awt.*;
import java.awt.event.*;
import java.beans.*;

public class WindowSwitch implements PropertyChangeListener
{
    public static void main(String[] argv) {
        Frame f1 = new Frame("1");
        f1.setBounds(100,100,100,100);
        Frame f2 = new Frame("2");
        f2.setBounds(210,100,100,100);

        KeyboardFocusManager.getCurrentKeyboardFocusManager().
            addPropertyChangeListener("focusedWindow", new WindowSwitch());
        f1.setVisible(true);
        f2.setVisible(true);
    }

    public void propertyChange(PropertyChangeEvent ev) {
        Window w1 = KeyboardFocusManager.getCurrentKeyboardFocusManager().
            getFocusedWindow();
        Window w2 = (Window)ev.getNewValue();
        System.out.println("w1 = " + w1 + ", w2 = " + w2);
    }
}
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