仿微博个人页滑动效果的实现

项目中有个人主页，顶部是个人信息，下面几个tab分别对应不同的帖子类型，和微博个人页很相似，效果如下：

weiboFinal.gif

实现思路：

最底部是一个左右滑动的UIScrollView，每个tab对应一个ContentViewController，将ContentViewController的view添加到ScrollView上；

lazy var bottomScrollView: UIScrollView = {
        let scrollView = UIScrollView(frame: CGRect(x: 0, y: 0, width: ScreenWidth, height: ScreenHeight))
        scrollView.showsVerticalScrollIndicator = false
        scrollView.showsHorizontalScrollIndicator = false
        scrollView.bounces = false
        scrollView.contentSize = CGSize(width: ScreenWidth * 4, height: ScreenHeight)
        scrollView.delegate = self
        scrollView.isPagingEnabled = true
        for i in 0...3 {
            let contentVC = ContentViewController()
            contentVC.view.frame = CGRect(x: ScreenWidth * CGFloat(i), y: 0, width: ScreenWidth, height: ScreenHeight)
            if i == 0 {
                contentVC.delegate = self
            }
            self.viewControllerArray.append(contentVC)
            self.addChildViewController(contentVC)
            scrollView.addSubview(contentVC.view)
        }
        return scrollView
    }()

顶部展示的个人信息和切换tab，添加到ScrollView的上层；

    lazy var headerView: UIView = {
        let view = UIView(frame: CGRect(x: 0, y: 0, width: ScreenWidth, height: HeaderHeight))
        view.backgroundColor = .red
        return view
    }()
    
    lazy var topScrollView: TabScrollView = {
        let scrollView = TabScrollView(frame: CGRect(x: 0, y: HeaderHeight, width: ScreenWidth, height: TopScrollHeight), nameArray: ["tab0","tab1","tab2","tab3"])
        scrollView.delegate = self
        scrollView.backgroundColor = .white
        return scrollView
    }()
    view.addSubview(bottomScrollView)
    view.addSubview(headerView)
    view.addSubview(topScrollView)

顶部个人信息的View肯定会遮挡ContentViewController的内容，要调整ContentViewController内容的开始位置，由于这里使用UITableView，通过调整contentInset的方式，注意这里contentInset的top要和headerView+topScrollView的高度一致

lazy var listTableView: UITableView = {
        let tableView = UITableView(frame: CGRect(x: 0, y: 0, width: ScreenWidth, height: ScreenHeight), style: .plain)
        tableView.contentInset = UIEdgeInsetsMake(285, 0, 0, 0)
        tableView.delegate = self
        tableView.dataSource = self
        tableView.backgroundColor = UIColorFromRGB(0xf5f3f0)
        return tableView
    }()

当ContentViewController中的tableview滑动时通过代理方法来改变顶部View的frame

  //ContentViewController
  func scrollViewDidScroll(_ scrollView: UIScrollView) {
        let offsetY = scrollView.contentOffset.y
        if self.delegate != nil && (self.delegate?.responds(to: #selector(ContentVCScrollDelegate.contentVCDidScrollContentOffset(_:))))! {
            self.delegate?.contentVCDidScrollContentOffset(offsetY)
        }
    }
  //Viewcontroller
  func contentVCDidScrollContentOffset(_ offsetY: CGFloat) {
        for contentVC in self.viewControllerArray {
            let height: CGFloat = -45 - 64
            if offsetY <= height {
                contentVC.listTableView.contentOffset = CGPoint(x: 0, y: offsetY)
            } else {
                let positionY = contentVC.listTableView.contentOffset.y
                if positionY < height {
                    //当某个tableview向上滑动露出headerview后，把所有的tableview滑动到顶部
                    contentVC.listTableView.contentOffset = CGPoint(x: 0, y: height)
                }
            }
        }
        
        let y = offsetY + HeaderHeight + TopScrollHeight
        
        let alpha = Float(y/64.0)
        topView.backgroundColor = UIColor(colorLiteralRed: 1.0, green: 1.0, blue: 1.0, alpha: alpha)
        lineView.backgroundColor = UIColor(colorLiteralRed: 237.0/255.0, green: 231.0/255.0, blue: 228.0/255.0, alpha: alpha)
        if y > 34 {
            UIView.animate(withDuration: 0.4, animations: {
                self.titleLabel.textColor = UIColorFromRGB(0xff7788)
                UIApplication.shared.setStatusBarStyle(.default, animated: true)
            })
        } else {
            UIView.animate(withDuration: 0.4, animations: {
                self.titleLabel.textColor = .white
                UIApplication.shared.setStatusBarStyle(.lightContent, animated: true)
            })
        }
        
        if y >= HeaderHeight - 64 {
            headerView.frame = CGRect(x: 0, y: -HeaderHeight + 64, width: ScreenWidth, height: HeaderHeight)
            topScrollView.frame = CGRect(x: 0, y: 64, width: ScreenWidth, height: 45)
        } else if y <= 0 {
            headerView.frame = CGRect(x: 0, y: 0, width: ScreenWidth, height: -y + HeaderHeight)
            topScrollView.frame = CGRect(x: 0, y: -y + HeaderHeight, width: ScreenWidth, height: 45)
        } else {
            headerView.frame = CGRect(x: 0, y: -y, width: ScreenWidth, height: HeaderHeight)
            topScrollView.frame = CGRect(x: 0, y: -y + HeaderHeight, width: ScreenWidth, height: 45)
        }
    }

当tab切换或底部的UIScrollView左右滑动后要确保只有一个ContentViewController触发代理事件

  func setDelegateWithOffset(_ offsetX: CGFloat) -> Void {
        for contentVC in self.viewControllerArray {
            contentVC.delegate = nil
        }
        let index = Int(offsetX)/Int(ScreenWidth)
        if index < viewControllerArray.count {
            let contentVC = viewControllerArray[index]
            contentVC.delegate = self
        }
    }

附源码地址，如有不足之处，欢迎指正。