如何使 iPhone 应用程序兼容多个 SDK(固件)版本 [英] How to make an iPhone app compatible with multiple SDK (firmware) versions

问题描述

随着 iOS 4 即将推出，我已经计划在我的应用程序的未来更新中包含一个 iAd.我认为这将使我的应用程序无法用于固件低于 4.0 的任何人.有没有办法根据用户的固件更改这些变量和 .xib 文件?

With iOS 4 coming out soon, I have already planned to include an iAd in a future update of an app of mine. I assume that this will make my app unusable for anyone on a firmware lower than 4.0. Is there a way to change those variables and the .xib file based on the user's firmware?

推荐答案

是的，您可以使用最新的 SDK(即:5.1)进行构建，并且仍然可以在具有较早版本固件 (SDK) 的设备上运行.

Yes, you can build with the latest SDK (ie: 5.1) and still run on devices with earlier versions of the firmware (SDK).

• 将您的部署目标设置为您希望能够运行的最早版本，即:3.0.
• 您将 Base SDK 设置为编译时使用的最新版本，即:5.0.这样您就可以在代码中引用较新的定义和符号.本文SDK 和部署目标" 详细讨论部署与基础 SDK.
• 使用仅在较新的 iOS 中可用的符号的库/框架的弱链接.这样您的应用就可以在没有更新符号的设备上运行.
• 您必须在调用之前检查是否有更新的方法可用.您必须确保仅当您的应用程序处于 < 时才调用 5.0 或 4.X 的方法.4.0 设备.当然，您必须通过使用旧方法或不支持需要新 SDK 支持的特定功能来优雅地处理旧版本.
• 新 w/XCode 4.2:要支持旧设备，您需要将 armv6 添加到构建中架构和从所需设备功能的 plist 中删除 armv7.

• Set your Deployment Target to the earliest version you want to be able to run with, ie: 3.0.
• You set your Base SDK to the latest version that you are compiling with, ie: 5.0. This way you can reference the newer definitions and symbols in your code. This article "SDK and Deployment Targets" discusses Deployment vs Base SDK in detail.
• Weak link to the libraries/frameworks with symbols that are only available in the newer iOS. This is so your app will run on a device that doesn't have the newer symbols.
• You must check to see that a newer method is available before calling it. You have to make sure not to call a method that is 5.0 or 4.X only when your app is on a < 4.0 device. Of course you have to gracefully handle working on older versions by either using older methods or not supporting particular features that need newer SDK support.
• NEW w/XCode 4.2: To support older devices you need to add armv6 to the build architectures and remove armv7 from the plist of required device capabilities.

有关更多详细信息，请参阅这些 SO 问题和答案:

See these SO questions and answers for more details:

• 部署目标与基础/活动 sdk
• 支持向后兼容的推荐方式
• 您如何在兼容 2.0 的应用程序中选择性地使用 iPhone 3.0 功能
• iPhone 开发弱链接框架
• 与 IB 的弱链接
• 通用 iphone/ipad 应用编译错误
• iphone 应用应包含 armv6

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