database - applicationDidEnterBackground：以及写入数据库的时间

Question

当应用程序终止时，我将数据写入数据库。

从 iOS 4 开始，没有调用 applicationWillTerminate:，我在 applicationDidEnterBackground: 和 applicationWillTerminate: 中都放置了相同的保存代码：

我读到 applicationDidEnterBackground: 中执行的任务需要一些时间。

那么，如果在数据库上的写入需要更多，我该如何管理呢？

Answer 1

You get 5 seconds to perform any saving etc in the applicationDidEnterBackground: method.

If you need more than 5 seconds there is this UIApplication method to request a background thread which will allow for more time to do whatever you need:

- (UIBackgroundTaskIdentifier)beginBackgroundTaskWithExpirationHandler:(void(^)(void))handler

Here is Apple's example code for this:

http://developer.apple.com/library/ios/documentation/iPhone/Conceptual/iPhoneOSProgrammingGuide/BackgroundExecution/BackgroundExecution.html#//apple_ref/doc/uid/TP40007072-CH5-SW12