iOS：Healthkit 实时获取氧饱和度

Question

我是 HealthKit 框架的新手，想要实时血流中的氧饱和度。

参考： https://github.com/coolioxlr/watchOS-2-heartrate

从这个仓库我试图查询氧饱和度

   func createOxygenSaturationStreamingQuery(_ workoutStartDate: Date) -> HKQuery? {

        guard let quantityType = HKObjectType.quantityType(forIdentifier: .oxygenSaturation) else { return nil }
        let datePredicate = HKQuery.predicateForSamples(withStart: workoutStartDate, end: nil, options: .strictEndDate )

        let predicate = NSCompoundPredicate(andPredicateWithSubpredicates:[datePredicate])

        let oxygenSaturationQuery = HKAnchoredObjectQuery(type: quantityType,
                                                       predicate: predicate,
                                                       anchor: nil,
                                                       limit: Int(HKObjectQueryNoLimit)) { (query, sampleObjects, deletedObjects, newAnchor, error) -> Void in

            self.updateOxygenSaturation(sampleObjects)
        }

        oxygenSaturationQuery.updateHandler = {(query, samples, deleteObjects, newAnchor, error) -> Void in
            self.updateOxygenSaturation(samples)
        }
        return oxygenSaturationQuery
    }

    func updateOxygenSaturation(_ samples: [HKSample]?) {

        guard let oxygenSaturationSamples = samples as? [HKQuantitySample] else {return}

        DispatchQueue.main.async {
            // RETURN FROM HERE AS EMPTY ARRAY
            guard let sample = oxygenSaturationSamples.first else { return }
            let value = sample.quantity.doubleValue(for: HKUnit(from: "%/min"))
            let stringValue = String(UInt16(value))
            self.label.setText(stringValue)
            // retrieve source from sample
            let name = sample.sourceRevision.source.name
            print("sample.sourceRevision.source.name : \(name)")
            print("PERCENT : \(stringValue)")
        }
    }

P.S：我正在模拟器中检查

我从那个 repo 获得心率，但氧气水平是空的？

让我知道我做错了什么以及如何改正？

Answer 1

watchOS 不会自动记录氧饱和度样本，因此您不应该期望得到任何结果，除非您的设备正在记录这种类型的样本并使用应用程序将它们写入 HealthKit。