Type 'ViewController' does not conform to protocol 'UICollectionViewDataSource'

[cbutelli]

Hi!

I'm very very new to coding and especially swift. followed your tutorial and am getting this error at the ViewController extension.

I made things a little different than your code, I am using a TableViewController as the starting point. This is the complete code for the subclass.

import UIKit
public let model: [[UIColor]] = generateRandomData()
class TableViewController: UITableViewController {


    override func viewDidLoad() {
        super.viewDidLoad()

        // Uncomment the following line to preserve selection between presentations
        // self.clearsSelectionOnViewWillAppear = false

        // Uncomment the following line to display an Edit button in the navigation bar for this view controller.
        // self.navigationItem.rightBarButtonItem = self.editButtonItem()
    }

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

    // MARK: - Table view data source

    override func numberOfSectionsInTableView(tableView: UITableView) -> Int {
        // #warning Incomplete implementation, return the number of sections
        return 0
    }


    // next two functions are to display table view cells
    override func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

        // ajustado
        return model.count
    }


    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath)

        return cell
    }

    // [kk2] set the collectionView delegate/datasource and row number one function to be called just before the cell is about to be displayed


    override func tableView(tableView: UITableView, willDisplayCell cell: UITableViewCell, forRowAtIndexPath indexPath: NSIndexPath) {
        guard let tableViewCell = cell as? TableViewCell else { return }

        tableViewCell.setCollectionViewDataSourceDelegate(self, forRow: indexPath.row)
        tableViewCell.collectionViewOffset = storedOffsets[indexPath.row] ?? 0

    }

    override func tableView(tableView: UITableView, didEndDisplayingCell cell: UITableViewCell, forRowAtIndexPath indexPath: NSIndexPath) {

        guard let tableViewCell = cell as? TableViewCell else { return }

        storedOffsets[indexPath.row] = tableViewCell.collectionViewOffset
    }






    /*
    override func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("reuseIdentifier", forIndexPath: indexPath)

        // Configure the cell...

        return cell
    }
    */

    /*
    // Override to support conditional editing of the table view.
    override func tableView(tableView: UITableView, canEditRowAtIndexPath indexPath: NSIndexPath) -> Bool {
        // Return false if you do not want the specified item to be editable.
        return true
    }
    */

    /*
    // Override to support editing the table view.
    override func tableView(tableView: UITableView, commitEditingStyle editingStyle: UITableViewCellEditingStyle, forRowAtIndexPath indexPath: NSIndexPath) {
        if editingStyle == .Delete {
            // Delete the row from the data source
            tableView.deleteRowsAtIndexPaths([indexPath], withRowAnimation: .Fade)
        } else if editingStyle == .Insert {
            // Create a new instance of the appropriate class, insert it into the array, and add a new row to the table view
        }    
    }
    */

    /*
    // Override to support rearranging the table view.
    override func tableView(tableView: UITableView, moveRowAtIndexPath fromIndexPath: NSIndexPath, toIndexPath: NSIndexPath) {

    }
    */

    /*
    // Override to support conditional rearranging of the table view.
    override func tableView(tableView: UITableView, canMoveRowAtIndexPath indexPath: NSIndexPath) -> Bool {
        // Return false if you do not want the item to be re-orderable.
        return true
    }
    */

    /*
    // MARK: - Navigation

    // In a storyboard-based application, you will often want to do a little preparation before navigation
    override func prepareForSegue(segue: UIStoryboardSegue, sender: AnyObject?) {
        // Get the new view controller using segue.destinationViewController.
        // Pass the selected object to the new view controller.
    }
    */

}

extension ViewController: UICollectionViewDelegate, UICollectionViewDataSource {
    func collectionView(collectionView: UICollectionView, numberOfRowsInSection section: Int) -> Int {

        return model[collectionView.tag].count
    }

    func collectionView(collectionView: UICollectionView, cellForItemAtIndexPath indexPath: NSIndexPath) -> UICollectionViewCell {

        let cell = collectionView.dequeueReusableCellWithReuseIdentifier("Cell", forIndexPath: indexPath)

        cell.backgroundColor = model[collectionView.tag] [indexPath.item]

        return cell
    }

}


func collectionView(collectionView: UICollectionView, didSelectItemAtIndexPath indexPath: NSIndexPath) {
    print("Collection view at row \(collectionView.tag) selected index path \(indexPath)")
}

It shows another two errors up there, which are Cannot invoke 'setCollectionViewDataSourceDelegate' with an argument list of type '(TableViewController, forRow: Int)'

and

Use of unresolved identifier 'storedOffsets'

both at one of the same override tableView function.

Any idea of what might be causing the problem?

[ashfurrow]

Hey there! Sorry to hear you're having issues. The storedOffsets problem looks like it's a problem with not having a storedOffsets property on your UITableViewController subclass (which this repo has here). The other issue, the setCollectionViewDataSourceDelegate looks more complicated. Assuming you have the same TableViewCell.swift class as this repo, then I imagine it may be a bug with Swift not inferring that self conforms to UICollectionViewDataSource and UICollectionViewDelegate. Can I ask you to try the following?

let castSelf = self as protocol<UICollectionViewDataSource, UICollectionViewDelegate>
tableViewCell.setCollectionViewDataSourceDelegate(castSelf, forRow: indexPath.row)