Show an activity Indicator for a UIView that takes quite a bit to show it self

I have an issue where my Moda开发者_如何学JAVAl view that I load, takes quite a bit to show up.. I am making no service calls.. It is just trying to process some local XML data and load the view. I would like to show an activity till I see my view take up the screen. Is there a way I can know when the view is gonna appear. viewWillAppear sounds right, but how do I use it to Notify the modal presenter?

Any help would be great!

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Without more detail about your implementation, it is not easy to answer properly.

Generally speaking, your view controller could keep a pointer to the object responsible for starting the activity indicator and send it a message when ready (from viewDidAppear, if everything is set so). Or, the notification could go through the parent controller to the view controller.

What I would do, is having a UIActivityIndicatorView as a subview of the "slow" view and displayed during the xml processing. So everything is managed through the same view controller; when the data is ready, you remove the indicator subview, and it's done.