What are the differences between this protocol definition?

Question

Lately, I got a little confused about defining methods for a fast protocol.

protocol OneDelegate : class

or

protocol OneDelegate : NSObjectProtocol

or

@objc protocol OneDelegate

or

@class_protocol protocol OneDelegate

And will we use the weak for the delegate? Or how  unowned(unsafe) var dataSource: UITableViewDataSource?

Thanks for the help!

Answer 1

The first and last are actually the same. Both indicate that the protocol can only be accepted by the class, i.e. The structure cannot accept the protocol. Form protocol OneDelegate : classis preferred. And @class_protocol protocol OneDelegateout of date.

The second case is a way to extend an existing protocol. Say, for example, you want your UITableViewDelegateanswer to a long press, then you can define the protocol:

protocol UITableViewDelegateWithRecognizer: UITableViewDelegate {
    func longPressed()
}

UITableViewDelegateWithRecognizer UITableViewDelegate longPressed.

@objc, , Objective-C. , , @objc.

, ARC Swift Objective-C, weak. , Swift , . . , , , , - , .. .