swift微博第14天(新特性的引导图)

import UIKit
private let reuseIdentifier = "Cell"
class NewFeatureCollectionViewController: UICollectionViewController {
private let pageCount = 3
private var layout: UICollectionViewFlowLayout = NewFeaturelayout()
// 因为系统初始化的构造方法是带参数的(UICollectionViewFlowLayout) 而不是不带参数的，所以不用加 override
init(){
    super.init(collectionViewLayout: layout)
    self.collectionView?.backgroundColor = UIColor.white
}
required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}
override func viewWillAppear(_ animated: Bool) {
    super.viewWillAppear(animated)
    /*
    //1.设置layout的布局
    layout.itemSize = UIScreen.main.bounds.size
    layout.minimumLineSpacing = 0
    layout.minimumInteritemSpacing = 0
    layout.scrollDirection = UICollectionViewScrollDirection.horizontal
    // 2.设置collectionView的属性
    collectionView?.showsHorizontalScrollIndicator = false
    collectionView?.bounces = false
    collectionView?.isPagingEnabled = true
    */
}
override func viewDidLoad() {
    super.viewDidLoad()
    // 1.注册一个cell
    collectionView?.register(newFeatureCell.self, forCellWithReuseIdentifier: reuseIdentifier)
}
// MARK: UICollectionViewDataSource UICollectionViewDelegate
override func numberOfSections(in collectionView: UICollectionView) -> Int {
    return 1
}
// 返回一共有多少个cell
override func collectionView(_ collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return pageCount
}
// cell的重写
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
    // 1.获取cell
    let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath) as! newFeatureCell
    // 2.设置cell的数据
    cell.ImageIndex = indexPath.item + 1
    // 3.返回cell
    return cell
}
override func collectionView(_ collectionView: UICollectionView, didEndDisplaying cell: UICollectionViewCell, forItemAt indexPath: IndexPath) {
    // 传递给我们的是上一页的索引
    let path = collectionView.indexPathsForVisibleItems.last
    print(path!)
}
override func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
    if indexPath.item == pageCount-1 {
          print("您点击的是租后一页,页码是第\(indexPath.item+1)页")
    }
}
   override func didReceiveMemoryWarning() {
      super.didReceiveMemoryWarning()
      // Dispose of any resources that can be recreated.
   }
}
// MARK: 自定义cell swift的一个文件里面可以定义多个类的
private class newFeatureCell: UICollectionViewCell
{
// 保存图片的索引
// 在swift里面,private修饰的东西如果是在同一个文件下是可以被调用的
var ImageIndex:Int?{
    didSet{
        iconView.image = UIImage(named:"guide_\(ImageIndex!).jpg")
    }
}
override init(frame: CGRect) {
    super.init(frame: frame)
    // 1.初始化UI
    setupUI()
}
required init?(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}
private func setupUI(){
    // 1.添加子控件到 UICollectionView 上
    contentView.addSubview(iconView)
    // 2.布局子控件的位置
    iconView.frame = contentView.frame
}
// MARK:- 懒加载
private lazy var iconView: UIImageView = {
    let iconViewImage = UIImageView()
    iconViewImage.contentMode = UIViewContentMode.scaleAspectFill
    iconViewImage.clipsToBounds = true
    return iconViewImage
}()
// MARK: 重写layout方法
private class NewFeaturelayout: UICollectionViewFlowLayout {
   override func prepare() {
    // 1.准备布局
    // 什么时候调用？ 1.先调用一个有 多少cell 2.调用准备布局，3.调用返回cell
    itemSize = UIScreen.main.bounds.size
    minimumLineSpacing = 0
    minimumInteritemSpacing = 0
    scrollDirection = UICollectionViewScrollDirection.horizontal
    // 2.设置collectionView的属性
    collectionView?.showsHorizontalScrollIndicator = false
    collectionView?.bounces = false
    collectionView?.isPagingEnabled = true
   }