问题
Hi I compiled an app in XCode 5 and all the UI changed. I was forced to customize the Navigation Bar and TabBar to make it look like iOS 5/6. Does Apple HIG prevent us from using Opaque Black navBar and TabBar in iOS 7?
回答1:
Well no, it doesn't necessarily mean that if your apps are running in iOS7, it needs to immediately have the new look. You can use iOS 7.0 as your base sdk but you need to do a custom modification in your app to implement the look and feel of iOS5/6 (but this is a tedious process...not recommended). Using 7.0 SDK will transform all appearance of UI Objects into iOS 7.0 objects (flat, no bezels, borderless, etc).
If you aren't ready yet to accept iOS 7 design in your application, you can still build your app using iOS 6.1 SDK. This will retain the previous look and feel of iOS UI, and will still run on iOS 7. Be careful though, some fonts (like Hirakaku pron) change their line spacing when they are run in iOS 7 (even though it is compiled against iOS 6.1). You may wanna do a forward compatibility check in iOS 7 for your iOS 6.1 Base SDK application.
(Cons of using iOS 6.1/6.0 as Base SDK: We still do not know if (or when) Apple will restrict submission of apps into iOS 7 only. But for now, uploading apps in iOS 6.1/6.0 is still ok.)
Summary:
Using iOS 7.0 as Base SDK: (Use Auto-Layout to properly design your objects)
- When you run application in iOS 7.0 device: UI objects will appear flat (NEW UI LOOK)
- When you run application in iOS 6.1 device and below: UI objects will retain their OLD LOOK
Using iOS 6.1/6.0 as Base SDK:
- When you run application in iOS 7.0 device: UI objects will retain their OLD LOOK
- When you run application in iOS 6.1 device and below: UI objects will retain their OLD LOOK
来源：https://stackoverflow.com/questions/18776627/do-apple-allow-custom-ios-5-6-style-ui-for-ios7