基于SDK 3.0到SDK 4.0

本文介绍了基于SDK 3.0到SDK 4.0的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！ 问题描述

我安装了SDK 4.0，发现我无法访问3.2之前的所有SDK版本。

I installed SDK 4.0 and found that I lost access to all previous SDK versions prior to 3.2.

我找到了下载SDK 3.1.3的链接所以我有.dmg安装文件。

I have found a link to download SDK 3.1.3 so I have both .dmg install files.

问题：

SDK 4.0不允许访问早期版本吗？

Does SDK 4.0 not allow access to earlier version?

如果上面的答案是否，那么这是否意味着我必须安装两个版本的SDK？

If the answer above is no then does that mean I have to have two versions of SDK installed?

如果以上是......怎么样？

If yes to the above....how?

谢谢你希望

推荐答案

术语令人困惑，但一旦你理解了这一点就很容易了。

The terminology is confusing but once you understand this it's easy.

'Base SDK'就是你正在编译的SDK的版本。因此，您可以使用Base SDK中的任何类，属性或方法。

The 'Base SDK' is just the version of the SDK that you are compiling against. So you can use any classes, properties, or methods in the Base SDK.

部署版本是您希望用户能够运行您的最早版本的操作系统代码反对。如果您使用Base SDK版本中提供但未在部署版本中使用的功能，则您的代码将在两个版本上启动，但在使用新功能时将在早期操作系统版本上崩溃，因此您需要检查新功能是否为目前，如果你想这样做。

The Deployment Version is earliest version of the OS that you want users to be able to run your code against. If you use a feature available in the Base SDK version but not in the Deployment version then your code will launch on both versions but will crash on the earlier OS version when you use the new feature, so you need to check if the new feature is present if you want to do this.

所以你不需要3.0的Base SDK在3.0上运行 - 只需将Base SDK设置为4.0，将部署版本设置为3.0和不要使用SDK中除3.0以外的任何功能。

So you don't need Base SDK of 3.0 to run on 3.0 - just set Base SDK to 4.0 and Deployment Version to 3.0 and don't use any features of the SDK that weren't present beyond 3.0.