zoukankan      html  css  js  c++  java
  • swift语言点评二十一-协议

    定义有什么,及哪些必须实现。

    protocol defines a blueprint of methods, properties, and other requirements that suit a particular task or piece of functionality.

    Property Requirements

    The protocol doesn’t specify whether the property should be a stored property or a computed property—it only specifies the required property name and type.

    1. protocol SomeProtocol {
    2. var mustBeSettable: Int { get set }
    3. var doesNotNeedToBeSettable: Int { get }
    4. }

    If you mark a protocol instance method requirement as mutating, you don’t need to write the mutatingkeyword when writing an implementation of that method for a class. The mutating keyword is only used by structures and enumerations.

    Class-Only Protocols

    You can limit protocol adoption to class types (and not structures or enumerations) by adding the AnyObjectprotocol to a protocol’s inheritance list.

    1. protocol SomeClassOnlyProtocol: AnyObject, SomeInheritedProtocol {
    2. // class-only protocol definition goes here

    协议联合体作为参量

    1. func wishHappyBirthday(to celebrator: Named & Aged) {
    2. print("Happy birthday, (celebrator.name), you're (celebrator.age)!")
    3. }
    4. let birthdayPerson = Person(name: "Malcolm", age: 21)
    5. wishHappyBirthday(to: birthdayPerson)
  • 相关阅读:
    C#中WinForm程序退出方法技巧(转载)
    webbrowser访问网站禁止弹窗
    (转载)ASP.NET三大核心对象及基础功能解析
    webBrowser调用外部js文件和js函数(转载)
    java IO流
    java线程状态,优先级
    java线程
    Collection接口,Map接口
    序列化和反序列化
    JsonUtil自定义
  • 原文地址:https://www.cnblogs.com/feng9exe/p/8745348.html
Copyright © 2011-2022 走看看