IOS(Swift)頁面頂部實現展開效果代碼，iosswift

IOS(Swift)頁面頂部實現展開效果代碼，iosswift

　　//懶載入    
　　//頂部需要展開自訂視圖    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)集合視圖    self.collectionView?.addSubview(self.headView) 
    override func collectionView(_ collectionView: UICollectionView, cellForItemAt     indexPath: IndexPath) -> UICollectionViewCell {        if indexPath.section == 0 { //頂部返回一個空的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  {//頂部            return CGSize(width: swidth, height:200.0 )        }....      //MARK:列表視圖    self.tableView?.addSubview(self.headView)  
    override func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {        if indexPath.section == 0 { //頂部返回一個空的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:展開效果實現位置    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: "搜尋方塊r")        }else{//上推           //if point.y >= (self.headView.frame.height - 64){                //self.mainNavView.searImg.image = UIImage(named: "搜尋方塊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))        }    }