如何在 Swift Xcode 6.4 的 TableView 中显示 Parse 数组

Question

如何将对象数组放入 theArray 以便在 tableView 中显示结果？由于查询是异步的，我不能简单地说 theArray = objects。那么，如何从查询中截取数组呢？

编辑：

Ashish 的回答解决了这个问题，但由于 Xcode 的建议，我不得不稍微更改一下代码。

现在，我试图打开它，因为我需要，

var new = object.objectId
println("first: \(new)")
if let tryToUnwrap = new as? NSString {
println("second: \(tryToUnwrap)")
}

我向下转换为 NSString 因为在 Swift 中字符串不是警告：从字符串转换？到不相关的类型'NSString'总是失败

代码有效，但它是什么意思？我怎么能摆脱这个？

import UIKit

import Parse


class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {

    @IBOutlet weak var myTableView: UITableView!

    var theArray : [PFObject] = []

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.

        //MARK: PFQUERY
        //***********************************************************************
        var query = PFQuery(className:"TestObject")

        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

                self.theArray = (objects as? [PFObject])!

                if self.theArray.count > 0 {
                    self.myTableView.reloadData()
                }

                if let objects = objects as? [PFObject] {
                    for object in objects {

//                        var new = object.objectId
//                        println("first: \(new)")
//                        
//                        if let tryToUnwrap = new as? NSString {
//                            println("second: \(tryToUnwrap)")
//                        }

                        println("here the object id: \(object.objectId)")

                    }
                }
            } else {
                // Log details of the failure
                println("Error: \(error!) \(error!.userInfo!)")
            }
        }
        //***********************************************************************
        //        if let string = dict.objectForKey("SomeKey") as? String {
        //            // If I get here, I know that "SomeKey" is a valid key in the dictionary, I correctly
        //            // identified the type as String, and the value is now unwrapped and ready to use.  In
        //            // this case "string" has the type "String".
        //            println(string)
        //        }

    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }



    //MARK: UITableViewDataSource (required to conform to UITableViewDataSource)
    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return theArray.count

    }

    //MARK: UITableViewDataSource (required to conform to UITableViewDataSource)
    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

        var cell : TaskCell = tableView.dequeueReusableCellWithIdentifier("myCell") as! TaskCell

        cell.objectIdLabel.text = theArray[indexPath.row].objectId

        return cell
    }


    //MARK: UITableViewDelegate (not required)
    func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
        println("section is: \(indexPath.section) row is: \(indexPath.row)")
    }

}

Answer 1

获取后重新加载表格即可。

    var query = PFQuery(className:"TestObject")
    //        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
            theArray = objects as? [PFObject]
            if theArray.count > 0 {
                  myTableView.reloadData()
            }
            if let objects = objects as? [PFObject] {
                for object in objects {
                    println(object.objectId)
                }
            }
        } else {
            // Log details of the failure
            println("Error: \(error!) \(error!.userInfo!)")
        }
    }

Answer 2

Parse 也有它自己的视图控制器 PFQueryTableViewController，它包含一个查询，然后设置表格视图中的单元格。我认为这可能对您的代码有用。

请参阅https://parse.com/docs/ios/guide#user-interface-pfquerytableviewcontroller 了解更多信息。

Answer 3

对于您的编辑，您是否想要代码：

var new = object.objectId
println("first: \(new)")
if let tryToUnwrap:String = new {
println("second: \(tryToUnwrap)")
}