How to use Reusable Cells in uitableview for IOS

Question

Ok. I cant seem to get a firm understanding on how tableviews work. Would someone please explain to me how cells are reused in tableviews especially when scrolling? One of t

Answer 1

Swift 2.1 version of accepted answer. Works great for me.

        override func viewDidLoad() {
        super.viewDidLoad();

        self.arrayProducts = NSMutableArray(array: ["this", "that", "How", "What", "Where", "Whatnot"]); //array from api for example
        var i:Int = 0;
        for (i = 0; i<=self.arrayProducts.count; i++){
            let numb:NSNumber = NSNumber(bool: false);
            self.arrayFavState.addObject(numb); //array of bool values
            }
        }

TablView Datasource methods ::

        func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
        let cell = tableView.dequeueReusableCellWithIdentifier("SubCategoryCellId", forIndexPath: indexPath) as! SubCategoryCell;


        cell.btnFavourite.addTarget(self, action: "btnFavouriteAction:", forControlEvents: UIControlEvents.TouchUpInside);

        var isFavourite: Bool!;
        isFavourite = self.arrayFavState[indexPath.row].boolValue;
        if isFavourite == true {
            cell.btnFavourite.setBackgroundImage(UIImage(named: "like-fill"), forState: UIControlState.Normal);
        } else {
            cell.btnFavourite.setBackgroundImage(UIImage(named: "like"), forState: UIControlState.Normal);
        }


        return cell;
    }

    func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return self.arrayProducts.count;
    }

Button Action method ::

        func btnFavouriteAction(sender: UIButton!){

        let position: CGPoint = sender.convertPoint(CGPointZero, toView: self.tableProducts)
        let indexPath = self.tableProducts.indexPathForRowAtPoint(position)
        let cell: SubCategoryCell = self.tableProducts.cellForRowAtIndexPath(indexPath!) as! SubCategoryCell
        //print(indexPath?.row)
        //print("Favorite button tapped")
        if !sender.selected {
            cell.btnFavourite.setBackgroundImage(UIImage(named: "like-fill"), forState: UIControlState.Normal);
            sender.selected = true;
            self.arrayFavState.replaceObjectAtIndex((indexPath?.row)!, withObject:1);
        } else {
            cell.btnFavourite.setBackgroundImage(UIImage(named: "like"), forState: UIControlState.Normal);
            sender.selected = false;
            self.arrayFavState.replaceObjectAtIndex((indexPath?.row)!, withObject:0);
        }

    }