ios 应用程序中的 APNS

Question

能否请您告诉我在函数中接收远程通知时使用 fetchCompletionHandler 的最佳实践:

- (void)application:(UIApplication *)application didReceiveRemoteNotification:(NSDictionary *)userInfo fetchCompletionHandler:(void (^)(UIBackgroundFetchResult result))completionHandler

我看到人们通常在上面的函数末尾写这段代码：

completionHandler(UIBackgroundFetchResultNewData);

如果我写：

completionHandler(UIBackgroundFetchResultNoData);

或者即使我不输入上面的代码会发生什么？

注：我用的是xcode7.1, objective-c, ios9.1

Answer 1

• UIBackgroundFetchResult.NewData - Called when new content has been fetched, and the application has been updated.
• UIBackgroundFetchResult.NoData - Called when the fetch for new content went through, but no content is available.
• UIBackgroundFetchResult.Failed - Useful for error handling, this is called when the fetch was unable to go through.

您必须调用它来让 iOS 知道后台获取的结果是什么。它使用此信息来安排未来的后台提取。

如果您不这样做，以后的后台提取可能会延迟 OS。

一个很好用的例子是here。

更新：不调用此处理程序的后果可能包括完全终止您的应用程序。