Swift纯代码走进UICollectionView

override func viewDidLoad() {
    super.viewDidLoad()
    var layout = UICollectionViewFlowLayout()
    colltionView = UICollectionView(frame: CGRectMake(0, 0, width, height), collectionViewLayout: layout)
    //注册一个cell
    colltionView! .registerClass(Home_Cell.self, forCellWithReuseIdentifier:"cell")
    //注册一个headView
    colltionView! .registerClass(Home_HeadView.self, forSupplementaryViewOfKind:UICollectionElementKindSectionHeader, withReuseIdentifier: "headView")
    colltionView?.delegate = self;
    colltionView?.dataSource = self;

    colltionView?.backgroundColor = UIColor.whiteColor()
    //设置每一个cell的宽高
    layout.itemSize = CGSizeMake((width-30)/2, 250)
    self.view .addSubview(colltionView!)
    self .getData()
}

//返回多少个组
func numberOfSectionsInCollectionView(collectionView: UICollectionView) -> Int {

    return 1
}
//返回多少个cell
func collectionView(collectionView: UICollectionView, numberOfItemsInSection section: Int) -> Int {
    return dataArr.count
}
//返回自定义的cell
func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

    let cell = collectionView.dequeueReusableCellWithReuseIdentifier("cell", forIndexPath: indexPath) as! Home_Cell
    var model = GoodsModel()
    model = dataArr[indexPath.row] as! GoodsModel
    let url : NSURL = NSURL(string: model.image_url as String)!
    cell.imgView!.hnk_setImageFromURL(url)
    cell.layer.borderWidth = 0.3;
    cell.layer.borderColor = UIColor.lightGrayColor().CGColor
    cell.titleLabel!.text = model.short_name
    cell.priceLabel!.text = "￥"+model.p_price
    cell.readLabel!.text = "?"+model.like_count
    return cell
}
//返回HeadView的宽高
func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, referenceSizeForHe
aderInSection section: Int) -> CGSize{

    return CGSize(width: width, height: height/1.6)
}


//返回自定义HeadView或者FootView，我这里以headview为例
func collectionView(collectionView: UICollectionView, viewForSupplementaryElementOfKind kind: String, atIndexPath indexPath: NSIndexPath) -> UICollectionReusableView{
    var v = Home_HeadView()
    if kind == UICollectionElementKindSectionHeader{

    v = colltionView!.dequeueReusableSupplementaryViewOfKind(kind, withReuseIdentifier: "headView", forIndexPath: indexPath) as! Home_HeadView
    }
    return v
}
//返回cell 上下左右的间距
func collectionView(collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAtIndex section: Int) -> UIEdgeInsets{
    return UIEdgeInsetsMake(5, 10, 5, 10)
}

//获取数据
func getData(){
    Alamofire.request(.GET, GoodsUrl).responseJSON() { (req, _, JSON, _) -> Void in

        if let j = JSON as? NSDictionary{
            var data = j.valueForKey("data")as! NSArray

            for dict in data{
                var model = GoodsModel()
                model.Analytical(dict as! NSDictionary)
                self.dataArr.addObject(model)
            }

            self.colltionView!.reloadData()
        }
    }
}

class Home_Cell: UICollectionViewCell {

    let width = UIScreen.mainScreen().bounds.size.width//获取屏幕宽
    var imgView : UIImageView?//cell上的图片
    var titleLabel:UILabel?//cell上title
    var priceLabel:UILabel?//cell上价格
    var readLabel:UILabel?//cell上的阅读量

override init(frame: CGRect) {

    super.init(frame: frame)
    //初始化各种控件
    imgView = UIImageView(frame: CGRectMake(0, -10, (width-30)/2, 200))
    self .addSubview(imgView!)
    titleLabel = UILabel(frame: CGRectMake(5, CGRectGetMaxY(imgView!.frame)-12, (width-40)/2, 50))
    titleLabel?.numberOfLines = 0
    titleLabel?.font = UIFont.boldSystemFontOfSize(14.0)
    titleLabel?.textColor = UIColor.lightGrayColor()
    self .addSubview(titleLabel!)

    priceLabel = UILabel(frame: CGRectMake(5, CGRectGetMaxY(titleLabel!.frame), (width-40)/2/2, 20))
    priceLabel?.numberOfLines = 0
    priceLabel?.font = UIFont.boldSystemFontOfSize(14.0)
    priceLabel?.textColor = UIColor.lightGrayColor()
    self .addSubview(priceLabel!)

    readLabel = UILabel(frame: CGRectMake((width-30)/2/2, CGRectGetMaxY(titleLabel!.frame), (width-40)/2/2, 20))
    readLabel?.numberOfLines = 0
    readLabel?.textAlignment = NSTextAlignment.Right
    readLabel?.font = UIFont.boldSystemFontOfSize(14.0)
    readLabel?.textColor = UIColor.lightGrayColor()
    self .addSubview(readLabel!)

}

required init(coder aDecoder: NSCoder) {
    fatalError("init(coder:) has not been implemented")
}

}

override func applyLayoutAttributes(layoutAttributes: UICollectionViewLayoutAttributes!){

}