如何在swift中解决错误“viewController与协议UIScrollViewDelegate的冗余一致性？

Question

I am new on stackOverflow and learning swift. I am getting the error "Redundant conformance of viewController to protocol while working with Stretch headers.UIScrollViewDelegate. I am specifying my code below. please correct any one .

class ViewController: UITableViewController , UIScrollViewDelegate {
    private let kTableHeaderHeight : CGFloat = 300.0
    // Using Implicitly Unwrapped Optional, UIView!
    var headerView:UIView!

    let items = [
    NewsItem(category: .World, summary: "Climate Change protests, Need to preserve our Ecosysytem"),
    NewsItem(category: .India, summary: "Climate Change protests, Need to preserve our Ecosysytem"),
    NewsItem(category: .America, summary: "Climate Change protests,Need to preserve our Ecosysytem"),
    NewsItem(category: .Japan, summary: "Climate Change protests, Need to preserve our Ecosysytem"),
    NewsItem(category: .China, summary: "Climate Change protests, Need to preserve our Ecosysytem"),
    NewsItem(category: .Nepal, summary: "Climate Change protests, Need to preserve our Ecosysytem")]
    override func viewDidLoad() {
        super.viewDidLoad()
        headerView = tableView.tableHeaderView
        tableView.tableHeaderView = nil
        tableView.addSubview(headerView)
   tableView.contentInset = UIEdgeInsetsMake(kTableHeaderHeight, 0, 0, 0)
        tableView.contentOffset = CGPointMake(0, -kTableHeaderHeight)
        updateHeaderView()
    }
    func updateHeaderView(){
        var HeaderRect = CGRectMake(0,-kTableHeaderHeight, tableView.bounds.width, kTableHeaderHeight)

        if tableView.contentOffset.y < -kTableHeaderHeight{
            HeaderRect.origin.y = tableView.contentOffset.y
            HeaderRect.size.height = -tableView.contentOffset.y
        }
        headerView.frame = HeaderRect
    }
    override func didReceiveMemoryWarning() {enter code here
        super.didReceiveMemoryWarning()   
    }
    override func scrollViewDidScroll(scrollView: UIScrollView) {
        updateHeaderView()
    }
    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return items.count
    }
    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let item = items[indexPath.row]
let cell = tableView.dequeueReusableCellWithIdentifier("Cell" forIndexPath: indexPath) as! NewsItemTableViewCell
        cell.newsItem = item
 return cell          
    }

Answer 1

You are getting this error because your class ViewController conforming to the protocol UIScrollViewDelegate in two ways. UITableViewController is already conforming to that protocol, you dont need to add it again. So remove UIScrollViewDelegate from there, you are good.

This is how it is UITableViewController conforms to UITableViewDelegate which conforms to UIScrollViewDelegate . This would be enough

class ViewController: UITableViewController{
}

Answer 2

The shortest explanation would be that Your UITableViewController comes with a built in scroll View, so you don't need a delegate for Scrollview. Remove UIScrollViewDelegate and you will be fine.

Feel free to ask any question :)