`
- 浏览:
177152 次
- 性别:
- 来自:
武汉
-
Initializers -- object-c中的alloc init的解释
At the beginning of this chapter, we talked about how an instance is created: its class is sent the message alloc, which creates an instance of that class and returns a pointer to it, and that instance is sent the message init. The init message isn’t a special type of instance method, though; it is simply a naming convention. Your initialization method could have a totally different name, like finishMakingInstance. However, by convention, all initialization methods begin with the word init. Objective-C is all about naming conventions, which you should strictly adhere to. (Seriously. Disregarding naming conventions in Objective-C results in problems that are worse than most beginners would imagine.)
The class NSObject implements a method named init. This is the initializer message you need to send to an instance of NSObject to initialize it. Because init is the main (or, in this case, only) initialization method for NSObject, we call it thedesignated initializer. Classes can have multiple initializers, but for every class, there is one designated initializer. The designated initializer must make sure that each of the instance variables has a valid value. Only then will the newly created instance be valid. (“Valid” has different meanings, but the meaning in this context is, “When you send messages to this object after initializing it, you can predict the outcome and nothing bad will happen.”) Typically, the designated initializer is the initialization method with the most arguments.
in Objective-C, classes can also receive messages. We call these class methods. (alloc is an example of a class method.)
分享到:
Global site tag (gtag.js) - Google Analytics
相关推荐
灰烬加载初始化器 一个很小的插件,用于在ember-cli中自动加载初始化程序和实例初始化程序文件。 此加载项对app/initializers和app/instance-initializers内部的文件进行迭代,并通过传递文件的解析名称来分别调用...
将此行添加到您的应用程序的Gemfile中: gem 'devise-auth0' 然后执行: $ bundle 或将其自己安装为: $ gem install devise-auth0 配置 在config/initializers/devise.rb : require 'devise/strategies/auth...
)用法将js-initializers添加到您的 Gemfile # Gemfilegem 'js-initializers' 将js-initializers添加到您的链轮清单: //= require js-initializers 等等! 您已准备好添加初始化程序: // app/assets/javascripts/...
C语言编程中常见的错误汇总,可以帮助C语言学习和使用者排除各种C语言编程中遇到的错误
Kubernetes Initializers工作原理介绍.pptx
JLX12864G-54202-PN 可以显示 128 列*64 行点阵单色图片,或显示 16*16 点阵的汉字 8 个*4行,或显示 8*16 点阵的英文、数字、符号 16 个*4 行。或显示 5*8 点阵的英文、数字、符号 21 个*8 行。
《你必须知道的495个C语言问题》以问答的形式组织内容,讨论了学习或使用C语言的过程中经常遇到的一些问题。书中列出了C用户经常问的400多个经典问题,涵盖了初始化、数组、指针、字符串、内存分配、库函数、C预...
The professional programmer’s Deitel® guide to C# 6 and object-oriented development for Windows® Written for programmers with a background in high-level language programming, C# 6 for Programmers ...
安装将此行添加到您的应用程序的Gemfile中: gem 'object_json_mapper' 然后执行: $ bundle 或将其自己安装为: $ gem install object_json_mapper 用法在config/initializers/object_json_mapper.rb为您的API设置...
-i - print default initializers for fields (definits) -l<num> - split strings into pieces of max <num> chars (splitstr) -lnc - output original line numbers as comments (lnc) -lradix<num>- display ...
UnchartedCode备用荚结构 这使我们可以使用其他类似的pod结构 ... |--initializers/ | | | |-- name.js | |--mixins/ | | | |-- name.js | |--utils/ | | | |-- name.js | |--pods/ | | | |--name/ | |
LINQ, Object/Collection Initializers OOP: Classes, Objects, Inheritance, Polymorphism, Interfaces WinForms, WPF, XAML, Event Handling WPF GUI/Graphics/Multimedia Silverlight® Lists, Queues, ...
LINQ, Object/Collection Initializers OOP: Classes, Objects, Inheritance, Polymorphism, Interfaces WinForms, WPF, XAML, Event Handling WPF GUI/Graphics/Multimedia Silverlight® Lists, Queues, ...
资源来自pypi官网。 资源全名:dodoo-initializer-0.5.1.tar.gz
Fiorion-Orion-geo 与Fiware中的Orion服务器对话的界面(地理定位)设定档依赖关系:HTTPParty- ://rubygems.org/gems/httparty 要配置gem,请创建文件config / initializers / fiware_orion_config.rb并添加客户端...
请解决中的问题,使得程序按照顺序输出数字。 在提交Pull Request之前,您可以在本地确保所有代码已经编译通过,并且通过了测试( mvn clean verify ) 注意!我们只允许您修改以下文件,对其他文件的修改会被拒绝:...
1.8 如何在C中实现不透明(抽象)数据类型? 5 1.9 如何生成“半全局变量”,就是那种只能被部分源文件中的部分函数访问的变量? 5 存储类型 6 1.10 同一个静态(static)函数或变量的所有声明都必须包含static ...
作者在网络版CFAQ列表的基础上进行了大幅度的扩充和丰富,结合代码示例,权威而且详细深入地解答了实际学习和工作中最常遇到的495个C语言问题,涵盖了初始化、数组、指针、字符串、内存分配、库函数、C预处理器等...
Redmine OmniAuth SAML插件 该插件基于为基于添加了SAML身份验证支持。 要求 Redmine >= 4.1.0 Ruby>= 2.4.10 Redmine插件: 正在安装 您可以先在查看插件的一般...cp plugins/redmine_saml/sample-saml-initializers
-i - output default initializers for all non-final fields -l<num> - split strings into pieces of maximum <num> chars (default: no) -lnc - annotate the output with line numbers (default: no) -nl - ...