I have a Windows Mobile application written in Java that uses AWT for the user interface. I am looking at porting the UI to SWT. I got a hold of the SWT libraries for windows mobile and I started looking at what work will be involved in actually porting it over. I think the first thing I have to decide is how to handle a large number of screens in the application.
In AWT the UI is basically a single java.awt.Frame with CardLayout. Each screen is then just an extension of java.awt.Panel, and is added to the Frame. Then whenever we need to change to a different screen we just set that panel to the top-most.
SWT doesn’t have such a layout manager (and I’m not even sure if that is the best/most efficient way of doing it anyway, since the system resources associated with every screen in the application are always held). One way I thought of doing it was that each screen would be its own org.eclipse.swt.widgets.Shell. Switching from one screen to another would involve a display manager class creating the new screen (shell) and disposing of the old one (not sure of the performance hit here of creating the shell and all of the widgets every time the screen is shown?). I am not sure though if having multiple shells in one mobile application is a good idea??
Does anyone have any suggestions on the best way to handle multiple screens in a mobile application using SWT? Is there an equivalent to the method we are currently using in AWT, i.e. CardLayout? Or am I right in thinking that this is not really the best way of doing it, given the use of resources for every screen, even if they are not being displayed?
So the answer to my own question seems to be that there is in fact a StackLayout in SWT, which is pretty much identical to CardLayout in AWT. So I can use that and the job of porting from one to the other is pretty easy because they act in the same way.