Parse Objects not retrieved nor presented in UITableView - ios

Question

I am querying parse objects from a relation pointer, and then presenting those objects in a UITableview. However, whenever I use my code to query nothing shows up and it is just blank. I have used this code before to query objects from parse but not from a relation. Any help on how to query it and present it would greatly be appreciated.
class MyGroupsHomePage: UITableViewController {
let cellidentifer = "MyGroupsCell"
var mygroupsdata: NSMutableArray = NSMutableArray()
func findcurrentuserobjects () {
var currentuser = PFUser.query()
currentuser!.whereKey("username", equalTo: PFUser.currentUser()!.username!)
currentuser!.findObjectsInBackgroundWithBlock { (object:[AnyObject]?, error: NSError?) -> Void in
if error == nil && object != nil {
if let object = object as? [PFObject] {
for objects in object {
let relation = objects.relationForKey("UserGroups")
let query = relation.query()
query?.findObjectsInBackgroundWithBlock({ (ob: [AnyObject]?, er: NSError?) -> Void in
if er == nil && ob != nil {
if let ob = ob as? [PFObject] {
for obs in ob {
self.mygroupsdata.addObject(obs)
}
}
}
})
}
}
}
self.tableView.reloadData()
}
}
override func viewDidLoad() {
super.viewDidLoad()
findcurrentuserobjects()
}
override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
return 1
}
override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return self.mygroupsdata.count
}
The GroupName object represents the column of objects I want to retrieve from the relation.
override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let cell: UITableViewCell = tableView.dequeueReusableCellWithIdentifier(cellidentifer, forIndexPath: indexPath) as! UITableViewCell
let mygroupdata: PFObject = self.mygroupsdata.objectAtIndex(indexPath.row) as! PFObject
cell.textLabel?.text = mygroupdata.objectForKey("GroupName")! as? String
return cell
}

Answer 1

When you call self.tableView.reloadData() there is no data added to mygroupsdata yet, because query?.findObjectsInBackgroundWithBlock is an asynchronous function that returns immediately. The callback that adds objects to mygroupsdata is excuted after you reload the tableview. Try to reload the tableview here:
query?.findObjectsInBackgroundWithBlock({ (ob: [AnyObject]?, er: NSError?) -> Void in
if er == nil && ob != nil {
if let ob = ob as? [PFObject] {
for obs in ob {
self.mygroupsdata.addObject(obs)
}
}
self.tableView.reloadData()
}
})