符合协议的Swift扩展

Question

我在Swift中创建符合协议的扩展时遇到了问题.

在Objective-C中,我可以创建一个符合协议的类别:

SomeProtocol.h

@protocol SomeProtocol
...
@end

UIView的+类别名称

#import SomeProtocol.h
@interface UIView (CategoryName) <SomeProtocol>
...
@end

我试图通过Swift扩展实现相同的功能

SomeProtocol.swift

protocol SomeProtocol {
    ...
}

UIView扩展

import UIKit
extension UIView : SomeProtocol {
...
}

我收到以下编译器错误:

类型'UIView'不符合协议'SomeProtocol'

Answer 1

请仔细检查您的扩展程序是否已实现协议中定义的所有方法.如果未实现函数a,那么将获得您列出的编译器错误.

protocol SomeProtocol {
    func a()
}

extension UIView : SomeProtocol {
    func a() {
        // some code
    }
}

Answer 2

//**Create a Protocol:**

protocol ExampleProtocol {
    var simpleDescription: String { get }
    func adjust()-> String
}


//**Create a simple Class:** 

class SimpleClass {

}

//**Create an extension:**

extension SimpleClass: ExampleProtocol {

    var simpleDescription: String {

    return "The number \(self)"
    }

    func adjust()-> String {

    return "Extension that conforms to a protocol"

    }


}

var obj = SimpleClass() //Create an instance of a class

println(obj.adjust()) //Access and print the method of extension using class instance(obj)

结果:符合协议的扩展

希望能帮助到你..!