Description Matt Di Iorio 2002-04-25 19:04:28 EDT

If an SWT and Swing component is in the same window the SWT component will not 
give up focus to the Swing component.

The following code creates a window with two components.  The top component is 
a Swing JTextField component and the bottom component is a SWT Text component.  

To see the problem do the following:
  1. Click in the top component (the lightweight).  It should have keyboard 
focus.  Type a few characters to verify.
  2. Click in the bottom component (the heavyweight).  It should have keyboard 
focus.  Type a few characters to verify.
  3. Now click in the top component.  It will not get focus.
  4. Switch to another application, then switch back to this test frame.  At 
this point the Swing component will have keyboard focus.
  5. Click in the bottom component.  It will have focus.
  6. Clicking in the top component will not give it focus.

Sometimes the top component gets into a wierd state where it displays the text 
cursor, but any characters typed are delivered to the bottom component.

The above behavior was seen with the 1.3.1_03 JRE and the swt-win32-2026.dll 
version of SWT and the M5 release of SWT running on Windows 2000.

This code does not exhibit focus problems when running on the 1.4.0 JRE.

-----------------------------------------

/*
 * Demonstrates a focus bug between SWT and Swing components.
 * To compile: Include swt.jar in the classpath.
 * To run: Include -Djava.library.path=<path to swt-win32-XXXX.dll> on the 
command line
 */

import java.awt.BorderLayout;
import java.awt.Canvas;
import java.awt.Panel;

import javax.swing.*;

import org.eclipse.swt.SWT;
import org.eclipse.swt.internal.awt.win32.SWT_AWT;
import org.eclipse.swt.layout.FillLayout;
import org.eclipse.swt.widgets.Display;
import org.eclipse.swt.widgets.Shell;
import org.eclipse.swt.widgets.Text;

public class BugTest {
	
	private DisplayThread displayThread;
	
	public BugTest() {
		displayThread = new DisplayThread();
		displayThread.start();
		
		JFrame frame = new JFrame();
		frame.setSize( 500, 500 );
		
		frame.setDefaultCloseOperation( JFrame.EXIT_ON_CLOSE );

		frame.getContentPane().setLayout( new BoxLayout( 
frame.getContentPane(), BoxLayout.Y_AXIS ) );

		frame.setVisible( true );

		frame.getContentPane().add( createLightweight() );
		frame.getContentPane().add( createHeavyweight() );
		
		frame.validate();
	}
	
	private JPanel createLightweight() {
		JPanel panel = new JPanel();
		panel.setLayout( new BorderLayout() );
		panel.add( new JTextField( 30 ), BorderLayout.CENTER );
		return panel;
	}
	
	private Panel createHeavyweight() {
		return new MyPanel();
	}
	
	public static void main(String[] args) {
		new BugTest();
	}

	private class MyPanel extends Panel {
		private Canvas canvas;
		
		public MyPanel() {
			canvas = new Canvas();
			setLayout( new BorderLayout() );
			add( canvas, BorderLayout.CENTER );
		}
		
		public void addNotify() {
			super.addNotify();
			displayThread.getDisplay().syncExec( new Runnable() {
				public void run() {
					Shell shell = SWT_AWT.new_Shell( 
displayThread.getDisplay(), canvas );
					shell.setLayout( new FillLayout() );
					Text text = new Text( shell, 
SWT.MULTI );
				}
			} );
		}
	}
	
	private class DisplayThread extends Thread {
		private Display display;
		
		public void run() {
			display = Display.getDefault();
			swtEventLoop();
		}
		
		private void swtEventLoop() {
			while( true ) {
				if (!display.readAndDispatch()) {
					display.sleep();
				}
			}
		}
		
		public Display getDisplay() {
			return display;
		}
	}
}