Swift: Table view superclass error

问题:

I have created a slide out menu using Swift. I have done this many times before, but when I created it today, I get this error (see screenshot). It could just be a simple mistake I have made.

Here is the code, that I think is causing the problem:

    override func tableView(tableView: UITableView!, cellForRowAtIndexPath indexPath: NSIndexPath!) -> UITableViewCell! {

    var cell:UITableViewCell? = tableView.dequeueReusableCellWithIdentifier("Cell")! as UITableViewCell

    if cell == nil{
        cell = UITableViewCell(style: UITableViewCellStyle.Default, reuseIdentifier: "Cell")

        cell!.backgroundColor = UIColor.clearColor()
        cell!.textLabel!.textColor = UIColor.darkTextColor()

        let selectedView:UIView = UIView(frame: CGRect(x: 0, y: 0, width: cell!.frame.size.width, height: cell!.frame.size.height))
        selectedView.backgroundColor = UIColor.blackColor().colorWithAlphaComponent(0.3)

        cell!.selectedBackgroundView = selectedView
    }

    cell!.textLabel!.text = tableData[indexPath.row]

    return cell
}

Screenshot:

UPDATE: I have tried removing override

Hope someone can help!

回答1:

The method does not override any method of the superclass because the signature is wrong.

The correct signature is

override func tableView(tableView: UITableView, 
  cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {

All parameters are non-optional types.

And use also the recommended method

let cell = tableView.dequeueReusableCellWithIdentifier(cellIdentifier,
                                           forIndexPath: indexPath)

which also returns always a non-optional type

回答2:

Make sure that your class implements UITableViewDelegate and UITableViewDataSource.

class MyController: UIViewController, UITableViewDelegate, UITableViewDataSource {
    // All your methods here
}

You won't need override keyword unless any other superclass already implements those methods.

回答3:

See this works for me

• Just confirm UITableViewDelegate and UITableViewDataSource
• Implement required methods

---

import UIKit

class ListViewController: UIViewController, UITableViewDelegate, UITableViewDataSource  {

    let containArray = ["One","two","three","four","five"]


    // MARK: - View Lifecycle
    override func viewDidLoad() {
        super.viewDidLoad()
    }
    override func viewWillAppear(animated: Bool) {
        super.viewWillAppear(animated)
    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }

    //MARK: Table view data source and delegate methods

    //Number of rows
    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return containArray.count
    }

    //Prepare Custom Cell
    func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell{

        let identifier = "simpleTextCell"
        var cell: SimpleTextCell! = tableView.dequeueReusableCellWithIdentifier(identifier) as? SimpleTextCell

        if cell == nil {
            tableView.registerNib(UINib(nibName: "SimpleTextCell", bundle: nil), forCellReuseIdentifier: identifier)
            cell = tableView.dequeueReusableCellWithIdentifier(identifier) as? SimpleTextCell
        }

        let dayName = containArray[indexPath.row]
        cell.lblProductName.text = dayName


        return cell
    }

    //Handle click
    func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
        self.performSegueWithIdentifier("productListSegue", sender: self)
    }
}

回答4:

Try to removing "!", declaration for this function is:

 func tableView(_ tableView: UITableView,cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell

and make sure you have set delegate and datasource of tableview to "self"