ios - 如何快速循环保存在后台

Question

我将数据作为数组存储在 NSUserDefaults 中。我需要使用 Parse Server 获取这些数据并将其存储在数据库中。当我尝试循环遍历数组并使用 saveInBackgroundWithBlock 时，循环会在 block 完成之前再次运行并设置新值。将此数据保存为数据库中的单独对象的最佳方法是什么？

let other = PFObject(className: "Other")
if (NSUserDefaults.standardUserDefaults().objectForKey("otherTypes") != nil) && (NSUserDefaults.standardUserDefaults().objectForKey("otherCosts") != nil) {
        otherCosts = NSUserDefaults.standardUserDefaults().objectForKey("otherCosts") as! [Double]

        otherTypes = NSUserDefaults.standardUserDefaults().objectForKey("otherTypes") as! [String]

        for costs in otherCosts {

            other.setObject(PFUser.currentUser()!.objectId!, forKey: "userId")
            other.setObject(otherTypes[i], forKey: "otherName")
            let cost = String(costs)
            other.setObject(cost, forKey: "otherCost")
            i = i + 1
            other.saveInBackgroundWithBlock({ (success, error) -> Void in
                if error == nil {
                    print("Success")
                    NSUserDefaults.standardUserDefaults().setObject(nil, forKey: "otherTypes")
                    NSUserDefaults.standardUserDefaults().setObject(nil, forKey: "otherCosts")
                } else {
                    print("Fail")
                }
            })
        } 

Answer 1

您需要在 for 循环内分配 PFObject ，否则您只是一遍又一遍地弄乱同一个对象。

if (NSUserDefaults.standardUserDefaults().objectForKey("otherTypes") != nil) && (NSUserDefaults.standardUserDefaults().objectForKey("otherCosts") != nil) {
        otherCosts = NSUserDefaults.standardUserDefaults().objectForKey("otherCosts") as! [Double]

        otherTypes = NSUserDefaults.standardUserDefaults().objectForKey("otherTypes") as! [String]

        for costs in otherCosts {
            let other = PFObject(className: "Other")
            other.setObject(PFUser.currentUser()!, forKey: "userId")
            other.setObject(otherTypes[i], forKey: "otherName")
            let cost = String(costs)
            other.setObject(cost, forKey: "otherCost")
            i = i + 1
            other.saveInBackgroundWithBlock({ (success, error) -> Void in
                if error == nil {
                    print("Success")
                    NSUserDefaults.standardUserDefaults().setObject(nil, forKey: "otherTypes")
                    NSUserDefaults.standardUserDefaults().setObject(nil, forKey: "otherCosts")
                } else {
                    print("Fail")
                }
            })
        }

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