assigning to uiimagepickercontrollerdelegate from incompatible type

I have added a UIImagePickerController to a UIViewController. I have assigned the UIImagePickerControllerDelegate to that UIViewController.

When I try to do

myPicker.delegate = self;

Xcode gifts me with this message: warning: assigning to id from incompatible type 'RootViewController *'

Then I added the UINavigationControllerDelegate protocol to the same UIViewController and the error message vanished.

So, do I have to add both protocols to the ViewController when I add a UIImagePickerController?

if the UIImagePickerController is a subclass of UINavigationController as stated on the docs, shouldn't this be automatic? Why do I have to add its parent's delegate protocol and not just the UIImagePickerControllerDelegate protocol?

Is this a bug or am I missing something?

thanks.

As you noted,

UIImagePickerController

inherits from

UINavigationController

. It uses the same

delegate

property though and doesn't declare a (hypothetical) "imagePickerDelegate" of its own, so your delegate has to conform to both protocols. It makes sense, because you're also assigning the same delegate to the

UINavigationController

part (that knows nothing about the image picker).

The API design is a bit questionable here in my opinion, but anyway, all methods in

UINavigationControllerDelegate

are optional, so it suffices to declare that you conform to the protocol and be done with it.

转载于:https://www.cnblogs.com/lisa090818/p/3363254.html