它在tableview的cellforrowatindexpath中崩溃，表示：“致命错误：在展开可选值时意外发现nil”

Question

I have two tableview on the same Collectionviewcell. When I run the application, it crashes in cellforrowatindexpath of tableview , says : "fatal error: unexpectedly found nil while unwrapping an Optional value"

Please find below some of my code -

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> 
UITableViewCell {

let cell = collectionView.dequeueReusableCell(withReuseIdentifier:     
reuseIdentifier, for: indexPathOfCollectionView as IndexPath) as!   
MyCustomCollectionViewCell

if(tableView == cell.graphTableView){

let cell:CustomGraphTableViewCell =   
tableView.dequeueReusableCell(withIdentifier: "CustomGraphTableViewCell") as!    
CustomGraphTableViewCell

return cell
    }
    else
    {
        let cell:MyCustomTableViewCell = 
 tableView.dequeueReusableCell(withIdentifier: "MyCustomTableViewCell") as!   
 MyCustomTableViewCell
        cell.nameLabel.text = namesArray[indexPath.row]
        return cell

    }
}

Can anyone please suggest the solution. Why is it happening and what can be the solution for the same?

Answer 1

In tableview UICollectionViewCell won't work, UICollectionViewCell is different class which is inherited from UICollectionReusableView and UITableViewCell is a different class from UICollectionViewCell and it is inherited from UIView , NSCoding , UIGestureRecognizerDelegate , so here, you have to use only uitableview cell for your tableview. Else it will crash.

When your tableview delegate method return some value not but null or 0, then datasource method of tableview will execute, that means when your tableview's delegate method have some value the

func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> 
UITableViewCell 

above method will now started executing and when it found

let cell = collectionView.dequeueReusableCell(withReuseIdentifier:     
reuseIdentifier, for: indexPathOfCollectionView as IndexPath) as!   
MyCustomCollectionViewCell

above statement, it will get crashed.

This is

let cell:MyCustomTableViewCell = 
 tableView.dequeueReusableCell(withIdentifier: "MyCustomTableViewCell") as!   
 MyCustomTableViewCell
        cell.nameLabel.text = namesArray[indexPath.row]
        return cell

only put this statement under the cellforRow datasource method, it will work accordingly.

Thanks

Answer 2

Please check this line

cell.nameLabel.text = namesArray[indexPath.row]

The cell.nameLabel is always accept string value, first convert into string value like this:

cell.nameLabel.text = namesArray[indexPath.row] as NSString