我可以在完成处理程序中保存价值吗

Posted 2023-02-23

【中文标题】我可以在完成处理程序中保存价值吗

【英文标题】：Can I save value in a completion Handler

【发布时间】：2014-11-22 05:30:51

【问题描述】：

事情就是这样，我想将今天的步骤保存到完成处理程序中的核心数据中。但是当我加载这个值时，编译器显示它为零。有什么解决办法吗？

 func fetchDataOfQuantityType(startDate: NSDate, endDate: NSDate, quantityType: HKQuantityType, completion:((NSArray, NSError!) -> Void)!)  

    // initial a predicate with startDate and endDate
    let predicate = HKQuery.predicateForSamplesWithStartDate(startDate, endDate: endDate, options: HKQueryOptions.StrictStartDate)

    // initialize a HKStatisticsQuery
    let query: HKStatisticsQuery = HKStatisticsQuery(quantityType: quantityType, quantitySamplePredicate: predicate, options: HKStatisticsOptions.CumulativeSum, completionHandler:  (query, results, error) in

        if error != nil  // if there is an error print it
            println("there is a \(error) occur")
            return
        
        // Mark: - Saving the data in to Core data

        var todaySteps = results.sumQuantity().doubleValueForUnit(HKUnit.countUnit())
        println("The totalstep for today is \(todaySteps)")
            var appDel: AppDelegate = (UIApplication.sharedApplication().delegate as AppDelegate)
            var context: NSManagedObjectContext = appDel.managedObjectContext!
            var newUser = NSEntityDescription.insertNewObjectForEntityForName("User", inManagedObjectContext: context) as NSManagedObject
            newUser.setValue(todaySteps, forKey: "todaysteps")
            )
    self.healthstore.executeQuery(query)

【参考方案1】：

您似乎没有保存上下文。试试

var error: NSError?
context.save(&error)

设置值之后。