CODEWITHSUNDEEP
iosuitableview
Wael
Wael

Reputation: 411

Swift 4 : UITableView cellForRow crash

I can't understand what I am doing wrong. I have a UITableView called TblView_Categorie, what I am trying to do is get the cell at desired indexpath:

Here is my code:

let myRecordindex = IndexPath(row: myRecordcheck, section: 0)

let cell = tblViewcategorie.cellForRow(at: myRecordindex) as! categorieTVC

The problem is if MyRecordIndex is shown screen (no scrolling needed) everything working fine

If MyRecordIndex is not shown on screen (scrolling needed) I have this error:

Thread 1: Fatal error: Unexpectedly found nil while unwrapping an Optional value

If I manually scroll to the desired index and I enter the desired MyRecordIndex everything working fine

I tried to automatically scrolling using the code below: the scroll work but still same error

   self.tblViewCategorie.scrollToRow(at: myRecordindex, at: UITableViewScrollPosition.middle, animated: true)

Why I have this error? All I am trying to do is getting the cell at desired indexpath to change color, font, etc.

// UPDATE cellForRowAt Implementation 

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

    let cell = tableView.dequeueReusableCell(withIdentifier: "Cell") as! categorieTVC
    if let categorieName = self.fetchedResultsController.object(at: indexPath).categorieName{
        cell.setListeDesCategories(categorieName: categorieName)
    }
    return cell
}

// Update code and crash screen shot

Crash and code

Upvotes: 2

Views: 1618

Answers (1)

Shehata Gamal
Shehata Gamal

Reputation: 100541

You can't explicit unwarp 

 let cell = TblView_Categorie.cellForRow(at: MyRecordIndex) as! CategorieTVC

as cell my be not visible so it will be nil -> crash

try

 let cell = TblView_Categorie.cellForRow(at: MyRecordIndex) as? CategorieTVC 

 if(cell != nil)
 {

 }

Edit : scroll to the cell and dispatch after the cellForRow

let myRecordindex = IndexPath(row: myRecordcheck, section: 0)

self.tblViewCategorie.scrollToRow(at: myRecordindex, at: UITableViewScrollPosition.middle, animated: true)

DispatchQueue.main.asyncAfter(deadline: .now() + 1.0 )) {

 let cell = TblView_Categorie.cellForRow(at: MyRecordIndex) as? CategorieTVC 

 if(cell != nil)
 {

 }
}

Upvotes: 3

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