Question

我希望我的应用程序在后台将所有服务器信息加载到Core Data实体。我创建了一个名为＆＃39; Event＆＃39;然后在其中创建了5个属性。另外，我为我的实体创建了NSManagedObject子类：

import Foundation
import CoreData

@objc(Event)
class Event: NSManagedObject {

    @NSManaged var category: String
    @NSManaged var date: String
    @NSManaged var event: String
    @NSManaged var location: String
    @NSManaged var time: String
}

以下是我如何加载所有数据并希望将其插入核心数据实体：

func loadAllData(){
    println("loading all data")

    let params = ServerConstants.infoParam + "=true"

    // creating request, set its method to POST and append params to request
    var request = NSMutableURLRequest(URL: NSURL(string: ServerConstants.getInfoURL)!)
    request.HTTPMethod = "POST"
    request.HTTPBody = params.dataUsingEncoding(NSUTF8StringEncoding, allowLossyConversion: false)

    // start loading data in background
    dispatch_async(dispatch_get_global_queue(DISPATCH_QUEUE_PRIORITY_HIGH, 0)) {
        var session = NSURLSession.sharedSession()
        var task = session.dataTaskWithRequest(request){ (data, response, error) -> Void in
            if error == nil {
                let json = JSON(data: data)
                self.defaults.setObject(json["lastCategoriesId"].string, forKey: "lastCategoriesId")
                self.defaults.setObject(json["lastEventsId"].string, forKey: "lastEventsId")

                //println(json)
                var maxValue = Float(json["categories"].count + json["events"].count)
                println("maxself. - \(maxValue)")

                var error: NSError?
                var array = json["events"]

                let newItem = NSEntityDescription.insertNewObjectForEntityForName("Event", inManagedObjectContext: self.managedObjectContext!) as! Event

                for var i: Int = 0; i < array.count; i++ {                        
                    newItem.category = array[i]["category"].string!
                    newItem.event = array[i]["event"].string!
                    newItem.location = array[i]["location"].string!
                    newItem.date = array[i]["date"].string!
                    newItem.time = array[i]["time"].string!

                    println(i)
                }
                if !self.managedObjectContext!.save(&error) {
                    println("Could not save \(error), \(error?.userInfo)")
                }
                println("done")
            }
        }
        task.resume()
    }
}

问题是我的for循环工作非常慢。一次迭代约1秒。我究竟做错了什么？数据大约是3500行。

这是我的json：

{
    "lastEventsId" : "3602",
    "events" : [
        {
            "date" : "lorem",
            "time" : "ipsum",
            "event" : "dolor",
            "category" : "sit",
            "location" : "amet"
        },...
}

我试着为循环运行：

for var i: Int = 0; i < array.count; i++ {
    println(i)
}

再次进行1次迭代1秒钟。但是，如果我只将索引最大长度设置为3500，则将整个循环迭代约1秒。

for var i: Int = 0; i < 3500; i++ {
    println(i)
}

Answer 1

也许swift每次都在计算array.count，和php count（array）一样尝试在const

中定义array.count

 let limit = array.count;
 for i in 0..<limit {
    //do your stuff
 }

核心数据在后台插入大数据

1 个答案: