ios - 在后台运行 URL 请求

Question

我想在一定的时间间隔内发出 url 请求(例如，应用程序应该每 10 分钟发出一次 url 调用并获取一些 json 数据)。应用程序在后台运行时应该能够执行此操作。这可以做到吗？如果是这样，这是否违反了 Apple 服务条款？有什么限制吗？

Answer 1

在 iOS 7 中添加了可以在后台运行的新应用程序列表。它们是:

1.  Apps that play audible content to the user while in the background, such as a music player app
2.  Apps that record audio content while in the background.
3.  Apps that keep users informed of their location at all times, such as a navigation app
4.  Apps that support Voice over Internet Protocol (VoIP)
5.  Apps that need to download and process new content regularly
6.  Apps that receive regular updates from external accessories

我们只需要在info.plist中声明app支持的后台任务即可。我们需要添加 我们应用的信息的UIBackgroundModes 键。 plist。之后，您可以正常使用计时器，例如:

UIBackgroundTaskIdentifier bgTask;

UIApplication  *app = [UIApplication sharedApplication];

bgTask = [app beginBackgroundTaskWithExpirationHandler:^{
    [app endBackgroundTask:bgTask]; 
}];

self.timer = [NSTimer scheduledTimerWithTimeInterval:600 target:self
selector:@selector(startServices) userInfo:nil repeats:YES];

希望对你有所帮助。