我们目前正在尝试让 HealthKit 在后台运行，以便在应用程序关闭时将步数数据传送到我们的服务器。

出于实验目的，我们在 XCode 中创建了一个全新的 iOS 项目，在 Compabilities 中启用了 HealhtKit 和所有后台模式。之后，我们几乎可以运行代码(见下文)。

那么首先发生的是应用程序当然会请求我们授予的权限。我们期望的是该应用程序应保持每小时向服务器传送步数数据。但它并没有那样做，似乎该应用程序在未处于事件状态时无法执行任何操作。

应用程序仅在恢复或启动时才传输数据，但根本不会从后台(软关闭/硬关闭)

appdelegate.m:

- (BOOL)application:(UIApplication *)application didFinishLaunchingWithOptions:(NSDictionary *)launchOptions {
    [self setTypes];
    return YES;
}


-(void) setTypes
{
    self.healthStore = [[HKHealthStore alloc] init];

    NSMutableSet* types = [[NSMutableSet alloc]init];
    [types addObject:[HKObjectType quantityTypeForIdentifier:HKQuantityTypeIdentifierStepCount]];

    [self.healthStore requestAuthorizationToShareTypes: types
                                             readTypes: types
                                            completion:^(BOOL success, NSError *error) {

                                                dispatch_async(dispatch_get_main_queue(), ^{
                                                    [self observeQuantityType];
                                                    [self enableBackgroundDeliveryForQuantityType];
                                                });
                                            }];
}

-(void)enableBackgroundDeliveryForQuantityType{
    [self.healthStore enableBackgroundDeliveryForType: [HKQuantityType quantityTypeForIdentifier: HKQuantityTypeIdentifierStepCount] frequency:HKUpdateFrequencyImmediate withCompletion:^(BOOL success, NSError *error) {
    }];
}


-(void) observeQuantityType{

    HKSampleType *quantityType = [HKSampleType quantityTypeForIdentifier:HKQuantityTypeIdentifierStepCount];

    HKObserverQuery *query =
    [[HKObserverQuery alloc]
     initWithSampleType:quantityType
     predicate:nil
     updateHandler:^(HKObserverQuery *query,
                     HKObserverQueryCompletionHandler completionHandler,
                     NSError *error) {

         dispatch_async(dispatch_get_main_queue(), ^{
             if (completionHandler) completionHandler();
             [self getQuantityResult];

         });
     }];
    [self.healthStore executeQuery:query];
}


-(void) getQuantityResult{

    NSInteger limit = 0;
    NSPredicate* predicate = nil;

    NSString *endKey =  HKSampleSortIdentifierEndDate;
    NSSortDescriptor *endDate = [NSSortDescriptor sortDescriptorWithKey: endKey ascending: NO];

    HKSampleQuery *query = [[HKSampleQuery alloc] initWithSampleType: [HKQuantityType quantityTypeForIdentifier:HKQuantityTypeIdentifierStepCount]
                                                           predicate: predicate
                                                               limit: limit
                                                     sortDescriptors: @[endDate]
                                                      resultsHandler:^(HKSampleQuery *query, NSArray* results, NSError *error){

                                                          dispatch_async(dispatch_get_main_queue(), ^{
                                                                // sends the data using HTTP
                                                              [self sendData: [self resultAsNumber:results]];

                                                          });
                                                      }];
    [self.healthStore executeQuery:query];
}

最佳答案

我不久前在与 Apple 的某个人交谈时发现了这一点。显然，如果设备被锁定，您将无法在后台访问 HK 数据:

NOTE

Because the HealthKit store is encrypted, your app cannot read data from the store when the phone is locked. This means your app may not be able to access the store when it is launched in the background. However, apps can still write data to the store, even when the phone is locked. The store temporarily caches the data and saves it to the encrypted store as soon as the phone is unlocked.

来自: https://developer.apple.com/library/ios/documentation/HealthKit/Reference/HealthKit_Framework/

关于ios - HealthKit (iOS) 不会在后台传递数据 (objC)，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/27593429/