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swift - Swift方法 header 的数据类型中的感叹号是什么意思

转载 作者:行者123 更新时间:2023-11-28 10:02:44 26 4
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我注意到一些方法,主要是在协议(protocol)中有一个!在他们的参数中。例如来自 UIImagePickerControllerDelegate 的这个:

protocol UIImagePickerControllerDelegate : NSObjectProtocol {
@optional func imagePickerController(picker: UIImagePickerController!, didFinishPickingImage image: UIImage!, editingInfo: NSDictionary!)
@optional func imagePickerController(picker: UIImagePickerController!, didFinishPickingMediaWithInfo info: NSDictionary!)
@optional func imagePickerControllerDidCancel(picker: UIImagePickerController!)
}

具体是什么意思!在这种情况下?

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