小编Tri*_*yen的帖子

   1. Abstraction
   2. Encapsulation
   3. Inheritance 
   4. Polymorphism 

如何最好地解释这些概念,例如,在采访中？

我找到了一些关于如何使用UICollectionView的教程.但他们只是在ViewController中编写它们.我想知道如何在另一个swift文件中编写UICollectionView.然后在我的ViewController类中调用它.这是我的UICollectionView代码.

import UIKit

class ViewController: UIViewController, UICollectionViewDelegateFlowLayout, UICollectionViewDataSource {

    var collectionView: UICollectionView!
    var ImageNames: [String] = ["photo", "photo1", "photo2", "photo3"]

    override func viewDidLoad() {
        super.viewDidLoad()

        let layout:UICollectionViewFlowLayout = UICollectionViewFlowLayout()
        layout.sectionInset = UIEdgeInsets(top: 20, left: 10, bottom: 10, right: 10)
        layout.itemSize = CGSize(width: 90, height: 120)

        collectionView = UICollectionView(frame: self.view.frame, collectionViewLayout: layout)
        collectionView.dataSource = self
        collectionView.delegate = self
        collectionView.registerClass(UICollectionViewCell.self, forCellWithReuseIdentifier: "Cell")
        collectionView.backgroundColor = UIColor.whiteColor()
        self.view.addSubview(collectionView)
    }

    func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
        return ImageNames.count
    }

    func collectionView(collectionView: UICollectionView, …