Working collection view example in swift

gistfile1.txt

//
//  ViewController.swift
//  CollectionView
//
//  Created by Paul McKellar on 8/13/16.
//  Copyright © 2016 Paul McKellar. All rights reserved.
//

import UIKit

class ViewController: UIViewController, UICollectionViewDelegate, UICollectionViewDataSource {

    var collectionView: UICollectionView!
    
    override func viewDidLoad() {
        super.viewDidLoad()
        
        let layout = UICollectionViewFlowLayout()
        layout.itemSize = CGSizeMake(100, 100)
        
        self.collectionView = UICollectionView(frame: self.view.frame, collectionViewLayout: layout)
        self.view.addSubview(collectionView)
        
        self.collectionView.delegate   = self
        self.collectionView.dataSource = self
        
        self.collectionView.registerClass(UICollectionViewCell.self, forCellWithReuseIdentifier: "cellIdentifier")
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
    }

    func numberOfComponentsInPickerView(pickerView: UIPickerView) -> Int {
        return 2;
    }
    
    func pickerView(pickerView: UIPickerView, numberOfRowsInComponent component: Int) -> Int {
        return 5;
    }

    func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 10;
    }
    
    func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {
        let cell = self.collectionView.dequeueReusableCellWithReuseIdentifier("cellIdentifier", forIndexPath: indexPath)
        cell.backgroundColor = UIColor.redColor()
        return cell
    }

    
}