iOS 后台获取和完成块

问题描述

我正在尝试定义此方法

- (void)backgroundFetchWithCompletion:(void(^)(UIBackgroundFetchResult))completionHandler;

但是我在 UIBackgroundFetchResult 上收到一个错误，说只允许没有类型的参数列表，我正在关注这个教程和这个 教程，这就是他们定义方法的方式.

However I am getting an error on UIBackgroundFetchResult saying a parameter list without types is only allowed, I was following this tutorial and this tutorial and that is how they define their method.

推荐答案

最后执行某个操作后，必须调用列表中的一个.

After executing some operation at the end you must call one in list.

目标-C

1. completionHandler(UIBackgroundFetchResultNewData);
2. completionHandler(UIBackgroundFetchResultFailed);
3. completionHandler(UIBackgroundFetchResultNoData);

迅捷

1. completionHandler(.NewData)
2. completionHandler(.Failed)
3. completionHandler(.NoData)

完整示例:

目标-C

- (void)application:(UIApplication *)application performFetchWithCompletionHandler:(void (^)(UIBackgroundFetchResult))completionHandler
{
  NSLog(@"performFetchWithCompletionHandler");
  //Perform some operation
  completionHandler(UIBackgroundFetchResultNewData);
}

迅捷

func application(application: UIApplication, performFetchWithCompletionHandler completionHandler: (UIBackgroundFetchResult) -> Void) {
  println("performFetchWithCompletionHandler")
  //Perform some operation
  completionHandler(.NewData)
}

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