invokeLater's run() method being called twice - blackberry

Question

In order to determine which screen to display next in my BlackBerry app I'm using the code below. For some strange reason, however, the code within run() gets executed twice when a menu item is selected by tapping onscreen yet only once when using the phone's keypad instead.
Any ideas what might be causing this?
protected boolean navigationClick(int status, int time)
{
switch (mainMenu.getSelectedIndex())
{
case 0:
UiApplication.getUiApplication().invokeLater(new Runnable()
{
public void run()
{
UiApplication.getUiApplication().pushScreen(new PollListScreen());
}
});
break;
case 1:
UiApplication.getUiApplication().invokeLater(new Runnable()
{
public void run()
{
UiApplication.getUiApplication().pushScreen(new UpdateProfileScreen());
}
});
break;
// Etc.
default:
break;
}
return true;
}

Answer 1

I can't see exactly where you've placed the code that you're showing, but I don't think too many things can be going wrong here.
If run() is being called multiple times, then I think navigationClick() is getting called multiple times.
navigationClick() can get called differently depending on the source of the click (e.g. touch vs. trackwheel). You should, however, be able to sort this out by inspecting the status parameter. Something like this might do for you:
protected boolean navigationClick(int status, int time)
{
if (status != 0) // <-- NOTICE THIS CHECK!!!
{
switch (mainMenu.getSelectedIndex())
{
case 0:
// your code cut out here for clarity
}
}
return true;
}
If you use invokeAndWait(), you're probably blocking the UI thread, which might cause problems for the second invocation of navigationClick(). That would be using two wrongs to make a right, though. invokeLater() should usually be preferred.