必须使用非nil布局参数初始化UICollectionView。 迅速与UICollectionView错误

Question

Hi guys so I am getting the following error - UICollectionView must be initialized with a non-nil layout parameter

The code For PopularShotsCollectionViewController-:

import UIKit

private let reuseIdentifier = "Cell"

class PopularShotsCollectionViewController: UICollectionViewController {
    private var shots : [Shot] = [Shot](){
        didSet{
            self.collectionView?.reloadData()
        }
    }

    var API_URl = Config.SHOT_URL
    var shotPages = 1
    private let leftAndRightPaddings : CGFloat = 32.0
    private let numberOFItemsPerRow : CGFloat = 3.0
    private let heightAdjustMent : CGFloat = 30.0

    override func viewDidLoad() {
        super.viewDidLoad()
      // Do any additional setup after loading the view.
        let width = (CGRectGetWidth(collectionView!.frame) - leftAndRightPaddings) /  numberOFItemsPerRow
        let layout = collectionViewLayout as! UICollectionViewFlowLayout
        layout.itemSize = CGSizeMake(width, width + heightAdjustMent)


        let popularShot = PopularShotsCollectionViewController()
        popularShot.title = "Popular"
        popularShot.API_URl = Config.POPULAR_URL
        popularShot.loadShots()

    }

    func loadShots(){

      DribbleObjectHandler.getShots(API_URl) { (shots) -> Void in
        self.shots = shots
     }
     let refreshControl = UIRefreshControl()
        refreshControl.addTarget(self, action: Selector("refreshInvoked:"), forControlEvents: UIControlEvents.ValueChanged)
        collectionView?.addSubview(refreshControl)
}

    func refreshInvoked(sender : AnyObject){
      sender.beginRefreshing()
      collectionView?.reloadData()
      sender.endRefreshing()
    }

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

   // MARK: UICollectionViewDataSource

    override func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        // #warning Incomplete implementation, return the number of items
        return shots.count
    }

    override func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCellWithReuseIdentifier(reuseIdentifier, forIndexPath: indexPath) as! PopularShotsCollectionViewCell
        // Configure the cell
       let shot = shots[indexPath.row]
        cell.imageView.sd_setImageWithURL(NSURL(string : shot.imageUrl))

        if shots.count - 1 == indexPath.row && shotPages < 5{
          shotPages++
          print(shotPages)
          let url = API_URl + "&page=" + String(shotPages)
          DribbleObjectHandler.getShots(url, callback: { (shots) -> Void in
            for shot in shots {
              self.shots.append(shot)
            }
          })
        }

        return cell
    }
}

This is Where The App Crashes

You can have a look at the log also

And if i try to debug any code after this line it automatically crashes without telling

I have checked in Main.storyboard and nothing and everything this is like it should be the classes are hooked up to the view so is the delegate and the data source

Please Bear in Mind i am only 12 and fairly new to Swift.. Any help will be really appreciated

Thanks In Advance Aryan Kashyap

Answer 1

I don't understand why you create a new instance of itself in viewdidload:

    let popularShot = PopularShotsCollectionViewController()
    popularShot.title = "Popular"
    popularShot.API_URl = Config.POPULAR_URL
    popularShot.loadShots()

I think this might be your issue where it gets stuck in a loop?

Can't you just use...

self.title = "Popular"
self.API_URl = Config.POPULAR_URL
self.loadShots()

...in viewDidLoad when the collectionViewController loads.

See if that makes a difference