//懒加载    
  //顶部需要拉伸自定义视图
lazy var headView:MyHeaderView = {
//let hframe = CGRect(x: 0, y: 0, width: swidth, height: swidth/self.imgRation)
// let hview = Bundle.main.loadNibNamed("MyInfoHeaderView", owner: nil, options: nil)?.first as! MyInfoHeaderView
//return hview;
}() //MARK:1)集合视图
self.collectionView?.addSubview(self.headView)
override func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
if indexPath.section == 0 { //顶部返回一个空的cell
let cell = collectionView.dequeueReusableCell(withReuseIdentifier: reuseIdentifier, for: indexPath)
return cell
}
.... func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
if indexPath.section == 0 {//顶部
return CGSize(width: swidth, height:200.0 )
}
.... //MARK:2)列表视图
self.tableView?.addSubview(self.headView)
override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if indexPath.section == 0 { //顶部返回一个空的cell
var cell = tableView.dequeueReusableCell(withIdentifier: reuseIdentifier)
return cell!
}
.... override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
if indexPath.section == 0{
return 200.0;
}
.... //MARK:拉伸效果实现位置
override func scrollViewDidScroll(_ scrollView: UIScrollView) {
let point = scrollView.contentOffset;
if point.y <= 0 {//下拉
//self.headView.frame.size.height = swidth/imgRation - point.y
//self.headView.frame.size.width = self.headView.frame.size.height*imgRation
//self.headView.frame.origin.x = (swidth - self.headView.frame.size.width)/2
//self.headView.frame.origin.y = point.y
//self.headView.titleImgLeft.constant = 18 - self.headView.frame.origin.x
//self.mainNavView.backgroundColor = UIColor.clear
//self.mainNavView.searImg.image = UIImage(named: "搜索框r")
}else{//上推
//if point.y >= (self.headView.frame.height - 64){
//self.mainNavView.searImg.image = UIImage(named: "搜索框w")
//self.mainNavView.searchText.backgroundColor = UIColor.white
//}
//self.headView.titleImgLeft.constant = 18
// self.mainNavView.backgroundColor = UIColor(red:245/255.0, green:74/255.0, blue:48/255.0, alpha: point.y/(self.headView.frame.height - 64))
}
} 
05-08 08:04