swift，为ios 7和8编写代码 [英] swift, write code for ios 7 and 8

问题描述

我有一个测试应用程序我正在用Swift编写，我想要定位iOS 7.但启用本地通知我需要添加

i got an test app I'm writing with Swift, I want to target iOS 7. But enable local notification I need to add

application.registerUserNotificationSettings(UIUserNotificationSettings(forTypes: UIUserNotificationType.Sound 
    | UIUserNotificationType.Alert 
    | UIUserNotificationType.Badge, 
    categories: nil))

但这个电话在iOS 7中不可用，所以我添加了

But this call is not available in iOS 7, so I added

var version:NSString = UIDevice.currentDevice().systemVersion as NSString;
if  version.doubleValue >= 8 {
    // ios 8 code
}

ios 8代码块仅在iOS 8（经测试）下运行，但在iOS 7中运行应用程序时，我仍然可以获得

The ios 8 code block is only run in under iOS 8 (Tested), but when run the app in iOS 7 I still get

dyld：未找到符号：_OBJC_CLASS _ $ _ UIUserNotificationSettings
引自：/var/mobile/Applications/AC73969D-1A4C-45AC-99CA-0B3982C1EE36/Timely.app/Timely
预期： /System/Library/Frameworks/UIKit.framework/UIKit
in /var/mobile/Applications/AC73969D-1A4C-45AC-99CA-0B3982C1EE36/Timely.app/Timely

dyld: Symbol not found: _OBJC_CLASS_$_UIUserNotificationSettings Referenced from: /var/mobile/Applications/AC73969D-1A4C-45AC-99CA-0B3982C1EE36/Timely.app/Timely Expected in: /System/Library/Frameworks/UIKit.framework/UIKit in /var/mobile/Applications/AC73969D-1A4C-45AC-99CA-0B3982C1EE36/Timely.app/Timely

我认为这是因为二进制文件包含iOS 7中不存在的api符号，但我如何解决这个问题？

I assume it's because the binary contains symbol to api that doesn't exist in iOS 7, but how do i resolve this?

推荐答案

不幸的是，我认为你遇到了当前的限制，请看这个

Unfortunately, I think you are running into a current limitation, see this

什么是Swift预处理器等同于iOS版本检查比较？

解决这个问题的唯一方法是添加一个Objective-C文件，然后使用 #if 宏并制作两个你从Swift调用的辅助函数（一个用于iOS8，一个用于iOS7）。我希望这会在某个时候得到修复。

The only way to get around this is to add an Objective-C file, and then use #if macros and make two helper functions that you call from Swift (one for iOS8 and one for iOS7). I expect this will be fixed at some point.

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