在iOS Swift中解析查询

Question

Irrespective of object ids,I want to retrieve all the data in a column. I have 10 usernames and all their game scores. I want to get all the usernames and corresponding game scores .What should be my query ? I have stored the usernames as well in the class.I want it in swift. TIA :)

var messages = [String]()
var usernames = [String]()

override func viewDidLoad() {
    super.viewDidLoad()

    var query = PFQuery(className: "RescuePost")
    query.findObjectsInBackgroundWithBlock {
        (objects, error) -> Void in

        if error == nil {
            if let objects = objects {
                for object in objects {
                    self.messages.append(object["message"] as! String)
                    self.usernames.append(object["username"] as! String)
                }
            }
        }
    }
}

Answer 1

If you want to download all those info you will need somewhere to put it , therefore let's create a data structure using the struct

 struct myDataStructure {
        var username:String?
        var userId:String?
        var message:String?
        var Userlocation:PFGeoPoint?
    }

Now let's create an array of that struct

var arrayOfData = [myDataStructure]()

Your query will look like that :

 func queryData()
    {
       let query = PFQuery(className: "NameOfClassYouWantToQueryFrom")
        query.findObjectsInBackgroundWithBlock { (objects :[PFObject]?, error :NSError?) -> Void in
            if error == nil
            {
                if let objects = objects
                {
                    for eachSingleUser in objects
                    {
                        let username = eachSingleUser["username"] as! String
                        let userId = eachSingleUser["userId"] as! String
                        let message = eachSingleUser["message"] as? String
                        let userLocation = eachSingleUser["location"] as? PFGeoPoint

                          var singleData = myDataStructure()
                           singleData.username = username
                           singleData.userId = userId
                           singleData.message = message
                           singleData.Userlocation = userLocation

                           self.arrayOfData.append(singleData)    
                          //<----- Since you are using UITableView don't forget to reload data
                    }
                }
            }
        }
    }

Some Explanation:

findObjectsInBackgroundWithBlock method is a method that returns all your data or objects from parse into an array of PFObjects. Therefore our job is to check and extract those data in order to use it :)

       let username = eachSingleUser["username"] as! String

In this line above, eachSingleUser is one of the many objects from parse that contains all your fields such as username, userId, message, therefore by using the subscript eachSingleUser[""] we will be able to access all those fields.

Finally :

   self.arrayOfData.append(singleData)  

In this line above we are saving each single objects into the array.

All your data is being saved and can be accessed in that array.

In cellPathRowAtIndexPath()

let data = arrayofData[indexPath.row]
 cell.textlabel.text = data.username
 cell.detailTextlabel.text = data.message

Answer 2

You want to get ALL objects of a class. You do this easily by constructing a basic query with no constraints, meaning your query will match with all records.

In your tableview, you access the values normally for each object:

object.objectForKey("username")