Adding buttons for each object in array

Question

I have an array of objects, and I want a button for each object in the array. Am I doing it correctly? The buttons are not showing up on the view, and I don't think the for loop is being called. I want the buttons to be in a random position, different for each button. What am I doing wrong? I am using parse to retrieve objects a certain distance from a point, which is working.

var locationarray = [AnyObject]()
var userbutton = [UIButton]()

  override func viewWillAppear(animated: Bool) {
    let userlocation = PFUser.query()
    PFGeoPoint.geoPointForCurrentLocationInBackground(){
        (point:PFGeoPoint?, error:NSError?) -> Void in
        NSLog("Test log 1") // Never printed

        if point != nil {
            // Succeeding in getting current location
            NSLog("Got current location successfully") // never printed
            PFUser.currentUser()!.setValue(point, forKey: "userlocation")
            PFUser.currentUser()!.saveInBackground()
        } else {
            // Failed to get location
            NSLog("Failed to get current location") // never printed
        }

        var query = PFUser.query()
        query?.whereKey("userlocation", nearGeoPoint: point!, withinMiles: 2.0)
        query?.findObjectsInBackgroundWithBlock({ (objects: [AnyObject]?, error: NSError?) -> Void in
            if(error == nil){
                for object in objects! {
                  self.locationarray.append(object)
                  print(self.locationarray)  
                }   
            }else{
                print(error)
            }
        })
    }

    for users in locationarray{
        let button = UIButton()
        button.addTarget(self, action: "buttonAction:", forControlEvents: .TouchUpInside)
        button.frame = CGRectMake(100, 100, 100, 50)

        let buttonWidth = button.frame.width
        let buttonHeight = button.frame.height

        // Find the width and height of the enclosing view
        let viewWidth = button.superview!.bounds.width
        let viewHeight = button.superview!.bounds.height


        let xwidth = viewWidth - buttonWidth
        let yheight = viewHeight - buttonHeight

        // Generate a random x and y offset
        let xoffset = CGFloat(arc4random_uniform(UInt32(xwidth)))
        let yoffset = CGFloat(arc4random_uniform(UInt32(yheight)))

        // Offset the button's center by the random offsets.
        button.center.x = xoffset + buttonWidth / 2
        button.center.y = yoffset + buttonHeight / 2

        self.userbutton.append(button)
        print("called")
        print(self.userbutton)
        self.view.addSubview(button)
    }
}

You need to call self.view.addSubview(button) to add the buttons the view — Paulw11
– Paulw11, Commented Dec 11, 2015 at 6:39
You are taking viewWidth and viewHeight from button.superview but you haven't added the button to the view at that point. You can use self.view rather than button.superView — Paulw11
– Paulw11, Commented Dec 11, 2015 at 6:50
Still does not work. I don't think the for loop is being called. The print("called") is not even showing up in the console. — stackerleet
– stackerleet, Commented Dec 11, 2015 at 6:55

Juri Noga · Accepted Answer · 2015-12-11 07:15:41Z

I've found problem in your code - findObjectsInBackgroundWithBlock is async function, and your location array loop is called before findObjectsInBackgroundWithBlock finishes. And since locationArray is empty at this point - for loop isn't called.

Try this, using this approach locationsSet is called only then, when all objects are received from server.

override func viewWillAppear(animated: Bool) {
  let userlocation = PFUser.query()
  PFGeoPoint.geoPointForCurrentLocationInBackground(){
    (point:PFGeoPoint?, error:NSError?) -> Void in
    NSLog("Test log 1") // Never printed

    if point != nil {
      // Succeeding in getting current location
      NSLog("Got current location successfully") // never printed
      PFUser.currentUser()!.setValue(point, forKey: "userlocation")
      PFUser.currentUser()!.saveInBackground()
    }else{
      // Failed to get location
      NSLog("Failed to get current location") // never printed
    }

    var query = PFUser.query()
    query?.whereKey("userlocation", nearGeoPoint: point!, withinMiles: 2.0)
    query?.findObjectsInBackgroundWithBlock({ (objects: [AnyObject]?, error: NSError?) -> Void in
      if(error == nil){
        for object in objects! {
          self.locationarray.append(object)
          print(self.locationarray)
        }

        self.locationsSet()

       }else{
         print(error)
       }
    })
  }
}

func locationsSet(){
  for users in locationarray{
    let button = UIButton()
    button.addTarget(self, action: "buttonAction:", forControlEvents: .TouchUpInside)
    button.frame = CGRectMake(100, 100, 100, 50)

    let buttonWidth = button.frame.width
    let buttonHeight = button.frame.height

    // Find the width and height of the enclosing view
    let viewWidth = self.view.bounds.width
    let viewHeight = self.view.bounds.height


    let xwidth = viewWidth - buttonWidth
    let yheight = viewHeight - buttonHeight

    // Generate a random x and y offset
    let xoffset = CGFloat(arc4random_uniform(UInt32(xwidth)))
    let yoffset = CGFloat(arc4random_uniform(UInt32(yheight)))

    // Offset the button's center by the random offsets.
    button.center.x = xoffset + buttonWidth / 2
    button.center.y = yoffset + buttonHeight / 2

    self.userbutton.append(button)
    print("called")
    print(self.userbutton)
    self.view.addSubview(button)
   }
}

See updated answer, I replaced button.supeview to self.view

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