从不调用PerformFetch

Question

我正在尝试在xamarin.ios应用程序中实现后台获取，尽管启用了后台获取，但从未得到调用。

public override bool FinishedLaunching (UIApplication app, NSDictionary options)
{
   // tried this also 
   // UIApplication.SharedApplication.SetMinimumBackgroundFetchInterval(UIApplication.BackgroundFetchIntervalMinimum);

   UIApplication.SharedApplication.SetMinimumBackgroundFetchInterval(60);

   // Other code
}


public override async void PerformFetch(UIApplication application, Action<UIBackgroundFetchResult> completionHandler)
{          
    Console.WriteLine("Perform fetch called..!!");
    var result = await FetchImage("https://www.xamarin.com/content/images/pages/branding/assets/xamagon.png");

    completionHandler(result);
}

Answer 1

您是否在info.plist中请求了正确的权限？

您将最低背景提取间隔设置为60，但建议不要低于900。

我建议看一下this xamarin blogpost about performing Background data fetches。详细并且很好地解释了。