Playing with CollectionViewController in playground

collectionview.swift

//: A UIKit based Playground for presenting user interface

import UIKit
import PlaygroundSupport



class MyCollectionVC: UICollectionViewController, UICollectionViewDelegateFlowLayout   {
    
    fileprivate let itemsPerRow = 3
    fileprivate let sectionInsets = UIEdgeInsets(top: 10.0, left: 10.0, bottom: 10.0, right: 10.0)
    
    override func viewDidLoad() {
        super.viewDidLoad()
        self.title = "Collection View Tutorial"
        self.collectionView?.backgroundColor = UIColor.red
        self.collectionView?.register(UICollectionViewCell.self, forCellWithReuseIdentifier: "cell")
        self.collectionView?.register(UICollectionReusableView.self, forSupplementaryViewOfKind: UICollectionElementKindSectionHeader, withReuseIdentifier: "header")
        
    }
    
    override func numberOfSections(in collectionView: UICollectionView) -> Int {
        return 5
    }
    
    override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return 5
    }
    
    override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
        let cell = collectionView.dequeueReusableCell(withReuseIdentifier: "cell", for: indexPath)
        cell.contentView.backgroundColor = UIColor.gray
        cell.contentView.layer.cornerRadius = 10
        cell.contentView.layer.maskedCorners = [.layerMinXMinYCorner, .layerMaxXMaxYCorner]
        return cell
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
        let paddingSpace = sectionInsets.left * CGFloat(itemsPerRow + 1)
        let width = self.view.frame.width - paddingSpace
        let widthPerItem = width / CGFloat(itemsPerRow)
        return CGSize(width: widthPerItem, height: widthPerItem)
        
    }
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
        return sectionInsets
    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, minimumLineSpacingForSectionAt section: Int) -> CGFloat {
        return sectionInsets.left
    }
    
//    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForFooterInSection section: Int) -> CGSize {
//        return CGSize(width: 300, height: 100)
//    }
    
    func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHeaderInSection section: Int) -> CGSize {
         return CGSize(width: self.view.frame.width, height: 50)
    }
    
    override func collectionView(_ collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, at indexPath: IndexPath) -> UICollectionReusableView {

        print(kind)
        var resuableView: UICollectionReusableView? = nil
        if kind == UICollectionElementKindSectionHeader {
            resuableView = collectionView.dequeueReusableSupplementaryView(ofKind: UICollectionElementKindSectionHeader, withReuseIdentifier: "header", for: indexPath)
            //resuableView?.frame = CGRect(x: 0, y: 0, width: self.view.frame.width, height: 50)
            resuableView?.backgroundColor = UIColor.green
        }
        
        return resuableView!
    }
    
    
}

let nav = UINavigationController(rootViewController: MyCollectionVC(collectionViewLayout: UICollectionViewFlowLayout()))

// Present the view controller in the Live View window
PlaygroundPage.current.liveView = nav