Threading a swing app basic question

[Sam]

All

I am fairly new at Swing and trying the foll.
Load an image to a Panel inside a SplitPane... and then make the
program to add another image after the first one. This is more of a
testing to learn threads better but here is the code i am faltering
with.

public class MyCanvas extends JFrame {

JSplitPane jSplitPane1 = new JSplitPane();

Image img;
JPanel jPanel1 = new JPanel();
VerticalFlowLayout verticalFlowLayout1 = new VerticalFlowLayout();


public MyCanvas() {
try {
setTitle("Frame Canvas");
jbInit();
} catch (Exception ex) {
ex.printStackTrace();
}
}

private void jbInit() throws Exception
{
this.getContentPane().add(jSplitPane1,
java.awt.BorderLayout.CENTER);
jPanel1.setLayout(verticalFlowLayout1);

// Adding the first image to be displayed.....
img = Toolkit.getDefaultToolkit().getImage("first.jpg");
img = img.getScaledInstance(70, 80, 0);
jPanel1.add(new JLabel(new ImageIcon(img)));
//
// Start running a thread to load one more...

Runnable updateComponent1 = new Runnable() {
public void run()
{
try
{
Thread.sleep(5000);
img =
Toolkit.getDefaultToolkit().getImage("second.jpg");
img = img.getScaledInstance(70, 80, 0);
jPanel1.add(new JLabel(new ImageIcon(img)));
} catch(Exception ex)
{
ex.printStackTrace();
}

validate();
}
};


javax.swing.SwingUtilities.invokeLater(updateComponent1);


}


public static void main (String args[]) {
MyCanvas frame = new MyCanvas();
frame.setSize(600,600);
frame.setLocationRelativeTo(null);
frame.setVisible(true);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
}
}

From what i understand the invokeLater should only halt (because of the

sleep in the runnable) on the second image from being displayed. But
for me the frame shows up w/o the first image and then both first and
the second show up together. I think i am missing something here.
Please assist.

Thanks
Sam

 

[sanjay manohar]

From what i remember, I think invokeLater runs the specified runnable
in the AWT event processing thread. therfore your Thread.sleep() would
hold up event processing! Not what you intended eh?
Try new Thread(runnable).start() instead of invokeLater?

 

[hilz]

in the AWT event processing thread. therfore your Thread.sleep() would
hold up event processing! Not what you intended eh?
Try new Thread(runnable).start() instead of invokeLater?

and probably call just this line (the one in the runnable class):
jPanel1.add(new JLabel(new ImageIcon(img)));
from yet another thread using invokeLater, to run only this line in the awt
event thread.

thanks
hilz