问题
How to notify a Composite if a new child control has been created?
The reason: by default, for the StackLayout no child is shown. I want to ensure that the first control which is added to our StackLayoutComposite (which is a Composite with set StackLayout and a few other helper methods) is shown by default. Currently, I solved it by overriding StackLayout's layout method, but this looks ugly in my eyes.
回答1:
If you want to re-layout the parent Composite based on the new child and any associated layout data, just use composite.layout(true);...
If you want to be notified by the parent that the widget hierarchy has been changed, then you're out of luck... The closest you can get, is to add a SWT filter to the display and wait for a SWT.Resize event for a previously unknown child... I have done this is a project, but I have to admit that the code gets a bit ugly as you have to monitor for disposal as well...
来源：https://stackoverflow.com/questions/6452856/swt-notify-a-composite-that-it-has-a-new-child