require that an object passed into an objective C method conform to a protocol?

Is this possible? For example, I have a class TriangleDataView with an init method. Currently the method is declared like this:

- (id)initWithFrame:(CGRect)frame delegate: (id) delegateObject;

I would like to require that delegateObject conform to the UIT开发者_如何转开发extFieldDelegate protocol. But what is the syntax for that?

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- (id)initWithFrame:(CGRect)frame delegate:(id<UITextFieldDelegate>)delegateObject;