在后台进程之后运行代码 - parse.com [英] Run code after a background process - parse.com

问题描述

我的 viewController 中有一个 findObjectsInBackgroundWithBlock 方法.现在我想执行代码，但直到这个后台方法完成.我该怎么做?

I have a findObjectsInBackgroundWithBlock method in my viewController. Now i want to execute code, but just until this background method is finished. How can i do that?

我正在使用 swift 编程语言.

I'm using the swift programming lanuage.

推荐答案

parse.com 上的文档和指南很好地涵盖了这一点.但也许您有更具体的问题/场景?

This is pretty well covered in the documentation and guide on parse.com. But maybe you have a more specific question/scenario?

parse.com 上的查询指南

var query = PFQuery(className:"GameScore")
query.whereKey("playerName", equalTo:"Sean Plott")
query.findObjectsInBackgroundWithBlock {
  (objects: [AnyObject]?, error: NSError?) -> Void in

  if error == nil {
    // The find succeeded.
    println("Successfully retrieved (objects!.count) scores.")
    // Do something with the found objects
    if let objects = objects as? [PFObject] {
      for object in objects {
        println(object.objectId)
      }
    }
  } else {
    // Log details of the failure
    println("Error: (error!) (error!.userInfo!)")
  }
}

PFUser 到用户名数组的特定版本

specific version for PFUser to array of usernames

var usernames: [String]?
func loadUsernames () {

    if let query = PFUser.query() {
        query.findObjectsInBackgroundWithBlock {
            (objects: [AnyObject]?, error: NSError?) -> Void in

            if error == nil { // No error - should be good to go

                self.userNames = (objects as! [PFUser]).map({$0.username!})

                // Call/run any code you like here - remember 'self' keyword
                // It will not run until userNames is populated
                self.callSomeMethod()

            } else { // Error - do something clever

            }
        }
    }
}

override func viewDidLoad() {
    super.viewDidLoad()
    loadUsernames()
}

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