Loading circle animation in iphone

How can I display the loading screen animation in iphone? I mean the bars arranged in circles. So that I can use it while some of the part of my app 开发者_如何学Cis loading, like initializing. Or should I create may own animation loading?

Thanks.

That's a class called UIActivityIndicatorView. You can either instantiate it as you would any other view in your code or you can drop it into a nib with Interface Builder.

The widget is called UIActivityIndicatorView.

Here is a good example of creating a loading view while waiting for something to happen http://cocoawithlove.com/2009/04/showing-message-over-iphone-keyboard.html