为什么我的 HKHealthStore.DeleteObjectAsync 方法没有在 Xamarin 中执行和返回对象？

Question

我正在尝试删除由我的 Xamarin.iOS 应用添加的 HKObject。我能够成功保存和查询 Apple HealthKit 中的数据，但 HKHealthStore.DeleteObjectAsync（和 HKHealthStore.DeleteObject）方法在运行后消失了。没有返回错误并且下一行代码没有被命中。以下是可用于重新创建问题的示例代码。由于没有响应或异常，我不确定从哪里开始尝试解决此问题。有谁知道我怎样才能让 DeleteObjectAsync（或 DeleteObject）在 Xamarin.iOS 中工作？

我正在使用的 AsyncHelpers 类的代码可以在 here 找到。

Zipped Project

public partial class ViewController : UIViewController
{
    string Id => "54b50df8-35ab-4f53-ac19-0ad0c3d3551a";

    protected ViewController(IntPtr handle) : base(handle)
    {
    }

    public override void ViewDidLoad()
    {
        base.ViewDidLoad();
    }

    partial void AddUsage(UIButton sender) //<- Button TouchUpInside
    {
        Tuple<HKUnit, double> entryItems = new Tuple<HKUnit, double>(HKUnit.CreateLiterUnit(HKMetricPrefix.Milli), 10);

        HKQuantity quantity = HKQuantity.FromQuantity(entryItems.Item1, entryItems.Item2);
        HKQuantityType qType = HKQuantityType.Create(HKQuantityTypeIdentifier.DietaryWater);
        HKMetadata metadata = new HKMetadata { ExternalUuid = Id };
        HKQuantitySample sample = HKQuantitySample.FromType(qType, quantity, new NSDate(), new NSDate(), metadata);
        using (HKHealthStore store = new HKHealthStore())
        {
            AsyncHelpers.RunSync(async () =>
            {
                Tuple<bool, NSError> saveResult = await store.SaveObjectAsync(sample);
            });

        }
    }

    partial void DeleteUsage(UIButton sender) //<- Button TouchUpInside
    {
        using (HKHealthStore store = new HKHealthStore())
        {
            NSCalendar calendar = NSCalendar.CurrentCalendar;
            NSDate now = new NSDate();
            NSDateComponents components = calendar.Components(NSCalendarUnit.Year | NSCalendarUnit.Month | NSCalendarUnit.Day, now);
            NSDate startDate = calendar.DateByAddingUnit(NSCalendarUnit.Day, -2, now, NSCalendarOptions.None);
            NSDate endDate = calendar.DateByAddingUnit(NSCalendarUnit.Day, 1, now, NSCalendarOptions.None);
            HKQuantityType qType = HKQuantityType.Create(HKQuantityTypeIdentifier.DietaryWater);
            NSPredicate pred = HKQuery.GetPredicateForSamples(startDate, endDate, HKQueryOptions.None);
            HKSampleQuery query = new HKSampleQuery(qType, pred, 0, null, (sampleQuery, results, error) =>
            {
                HKObject[] arr = results.Where(r => r.Metadata.ExternalUuid == Id).ToArray();
                if (arr.Length > 0)
                {
                    AsyncHelpers.RunSync(async () =>
                        {
                            Tuple<bool, NSError> deleteResult = await store.DeleteObjectAsync(arr.First()); // <- The breakpoint on this line is hit
                            string s = "s"; // <- The breakpoint on this line isn't ever hit
                        });
                }
            });
            store.ExecuteQuery(query);
        }
    }
}

Answer 1

几件事：

1) 根据HealthKit docs

每个应用只需要一个 HealthKit 商店。这些是长寿的对象。创建一次商店，并保留参考以供以后使用。

因此，您不应将 HKHealthStore 包装在 using 语句中。

2) 您的 AsyncHelpers 正在吃异常或做一些其他奇怪的事情，可能是因为您在尝试删除时处于后台线程回调的上下文中。

此更新后的代码有效：

public partial class ViewController : UIViewController
{
    HKHealthStore Store = new HKHealthStore();

    string Id => "54b50df8-35ab-4f53-ac19-0ad0c3d3551a";

    protected ViewController(IntPtr handle) : base(handle)
    {
    }

    public override void ViewDidLoad()
    {
        base.ViewDidLoad();
    }

    partial void AddUsage(UIButton sender) //<- Button TouchUpInside
    {
        Tuple<HKUnit, double> entryItems = new Tuple<HKUnit, double>(HKUnit.CreateLiterUnit(HKMetricPrefix.Milli), 10);

        HKQuantity quantity = HKQuantity.FromQuantity(entryItems.Item1, entryItems.Item2);
        HKQuantityType qType = HKQuantityType.Create(HKQuantityTypeIdentifier.DietaryWater);
        HKMetadata metadata = new HKMetadata { ExternalUuid = Id };
        HKQuantitySample sample = HKQuantitySample.FromType(qType, quantity, new NSDate(), new NSDate(), metadata);

        Task.Run(async () =>
        {
            try
            {
                var save = await Store.SaveObjectAsync(sample);
                System.Diagnostics.Debug.WriteLine($"{save}");
            }
            catch (Exception ex)
            {
                System.Diagnostics.Debug.WriteLine($"{ex}");
            }
        });
    }

    partial void DeleteUsage(UIButton sender) //<- Button TouchUpInside
    {
        NSCalendar calendar = NSCalendar.CurrentCalendar;
        NSDate now = new NSDate();
        NSDateComponents components = calendar.Components(NSCalendarUnit.Year | NSCalendarUnit.Month | NSCalendarUnit.Day, now);
        NSDate startDate = calendar.DateByAddingUnit(NSCalendarUnit.Day, -2, now, NSCalendarOptions.None);
        NSDate endDate = calendar.DateByAddingUnit(NSCalendarUnit.Day, 1, now, NSCalendarOptions.None);
        HKQuantityType qType = HKQuantityType.Create(HKQuantityTypeIdentifier.DietaryWater);
        NSPredicate pred = HKQuery.GetPredicateForSamples(startDate, endDate, HKQueryOptions.None);
        HKSampleQuery query = new HKSampleQuery(qType, pred, 0, null, (sampleQuery, results, error) =>
        {
            HKObject[] arr = results.Where(r => r.Metadata.ExternalUuid == Id).ToArray();
            if (arr.Length > 0)
            {
                Task.Run(async () =>
                {
                    try
                    {
                        var delete = await Store.DeleteObjectAsync(arr.First());
                        System.Diagnostics.Debug.WriteLine($"{delete}");
                    }
                    catch (Exception ex)
                    {
                        System.Diagnostics.Debug.WriteLine($"{ex}");
                    }
                });
            }
        });
        Store.ExecuteQuery(query);
    }
}