iphone - iOS 模拟器 : Application can't terminate correcly

Question

我有一个应用程序，在终止时需要同步 sqlite 数据库的内容。
为了知道应用程序何时终止，我在应用程序委托(delegate)的 applicationWillTerminate: 方法中放置了一个断点。但调试器永远不会走到那里。
我知道两种终止应用程序的方法:

1. 就像我在 iPhone 中做的那样:持续触摸应用程序图标直到它开始颤抖，然后我点击“x”；
2. 停止调试器。

这两种方法都不会导致调试器进入我的应用委托(delegate)的 applicationWillTerminate: 方法。
如果我使用第一种方法，我什至会遇到异常:我在这一行收到 SIGKILL:

return UIApplicationMain(argc, argv, nil, NSStringFromClass([AppDelegate class]));

即使没有针对该信号的处理程序，模拟器似乎也会启动 SIGKILL。
最后调用的消息是 mach_msg_trap。

Answer 1

来自文档

For applications that do not support background execution or are linked against iOS 3.x or earlier, this method is always called when the user quits the application. For applications that support background execution, this method is generally not called when the user quits the application because the application simply moves to the background in that case. However, this method may be called in situations where the application is running in the background (not suspended) and the system needs to terminate it for some reason.

您可能需要 applicationWillResignActive:。