iOS：在应用程序开始时初始化所有控制器使用的对象 [英] iOS: Initialise object at start of application for all controllers to use

问题描述

我需要的是一个在启动时初始化的对象，并且在应用程序关闭之前可供所有控制器使用。

该对象将保存从数据库（sql）或本地存储装载的数据 - 我不是100％确定的，但此处该做什么。

我需要所有viewController始终访问该数据存储对象，并且我需要在应用程序进入后台时保留该对象。

是否可以实现？如果，那么我会怎么做？

对于简单变量我知道我可以使用extern变量，但它也适用于完整对象吗？

感谢您的回答，
sebastian

解决方案

这里更常见的问题。我建议远离 extern 变量和单身人士，请参阅我对此相关问题的回答和这个示例Xcode项目，以获得更好的解决方案。 （该示例项目目前非常简单，稍后我会添加更多常见方案。）

i'm working on a little iOS project, and i stumbled across a problem with variable scoping.

what i need is an object that is initialised at launchtime, and is available to all controllers until the application closes.

the object will hold data that is loaded either from a database (sql) or from local storage - im not 100% sure yet what to do here.

i need all viewControllers to access that data-holding object at all times, and i need the object to retain when the app enters the background.

is this possible to achieve? and if, then how would i do it?

for simple variables i know i can use extern variables, but does it also work for complete objects?

thanks for an answer, sebastian

解决方案

This is one of the more common questions here. I would advise to stay away from extern variables and singletons, see my answer for this related question and this sample Xcode project for a better solution. (The sample project is very bare-bones at the moment, I will add more common scenarios later.)

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