Simple UITableView in Swift - unexpectedly found nil - ios

Question

Pretty simple code:
func numberOfSectionsInTableView(tableView: UITableView?) -> Int {
return 1
}
func tableView(tableView:UITableView!, numberOfRowsInSection section:Int) -> Int {
return 5
}
func tableView(tableView:UITableView!, cellForRowAtIndexPath indexPath:NSIndexPath!) -> UITableViewCell! {
let cell: BookTableViewCell = BookTableViewCell(style: UITableViewCellStyle.Default, reuseIdentifier: "BookCell")
println("ip: \(indexPath.row)")
cell.bookLabel.text = "test"
return cell
}
On the cell.bookLabel.text line I get this:
fatal error: unexpectedly found nil while unwrapping an Optional value
The BookTableViewCell is defined like this:
class BookTableViewCell: UITableViewCell {
#IBOutlet var bookLabel: UILabel
override func awakeFromNib() {
super.awakeFromNib()
// Initialization code
}
override func setSelected(selected: Bool, animated: Bool) {
super.setSelected(selected, animated: animated)
// Configure the view for the selected state
}
}
And bookLabel is correctly hooked up in a Prototype cell in the Storyboard. Why am I getting this error?

Answer 1

If you're using storyboard, make sure you don't have this line at the start of your file:
self.tableView.registerClass(CustomTableViewCell.self, forCellReuseIdentifier: "customCell")
It will overwrite the storyboard and as a result, the outlet links in the storyboard are ignored.

Answer 2

I was getting this error because I didn't have the identifier written in the Storyboard of the Custom Cell.
Also make sure it matches you code in:
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell
{
let cell = tableView.dequeueReusableCellWithIdentifier("CustomTableCell") as CustomTableCell
...
}

Answer 3

Possibly that your view in Main.Storyboard lost its IBOutlet reference in ViewController file, just link it again.

Answer 4

When you create a view in code, its IBOutlet properties don't get hooked up properly. You want the version that you get back from dequeueReusableCellWithIdentifier:
let cell = tableView.dequeueReusableCellWithIdentifier("BookCell") as BookTableViewCell

Answer 5

Do not forget to register nib (tested with Swift3), e. g. inside override func viewDidLoad():
self.tableView.register(UINib(nibName: "BookTableViewCell", bundle: nil), forCellReuseIdentifier: "BookCell")

Answer 6

The reason why this question gets asked a lot is because it depends on how you setup your tableview and custom CellClass. Do you create your tableview in storyboard or programmatically? Do you create custom .xib Cells and custom Cell classes?
If you created your tableview programmatically and created custom .xib and Cell class here is the answer for Swift 4:
in viewDidLoad:
customTable.register(UINib(nibName: "NibName", bundle: nil), forCellReuseIdentifier: "NibNameIdentifier")
in cellforRowat:
let cell = tableView.dequeueReusableCell(withIdentifier: "NibName") as! ClassName
Note: In your cell .xib file make sure you set your identifier in the Attributes inspector ("NibNameIdentifier").

Answer 7

You need to check two things
1. Register cell with nib name in viewDidLoad
func viewDidLoad()
{
super.viewDidLoad()
listTableView.register(UINib.init(nibName: "ListProductCell", bundle: nil), forCellReuseIdentifier: "ListProductCell")
}
2. Create custom cell this way.
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "ListProductCell") as! ListProductCell
return cell
}

Answer 8

Swift 5
In same storyboard two class are there Class A and Class B, Class B contains tableview outlet, when i tried to push Class A to Class B it's crashed and show tableView outlet nil.
In class A i did navigation like below code.
let classBObj = ClassB()
self.navigationController?.pushViewController(classBObj, animated: true)
Then i realised my mistake and used below code and it's work perfectly.
let storyboard = UIStoryboard(name: "Main", bundle: nil)
let classBObj = storyboard.instantiateViewController(withIdentifier: "ClassB") as! ClassB
self.navigationController?.pushViewController(classBObj, animated: true)

Answer 9

In my case it was the way the Optional is unwrapped:
let cellId:String = "ConverterTableCell"
let cell: ConverterTableViewCell = (tableView.dequeueReusableCellWithIdentifier(cellId)! as? ConverterTableViewCell)!

Answer 10

Try doing this:
let cell = tableView.dequeueReusableCellWithIdentifier("BookCell", forIndexPath: indexPath) as! BookTableViewCell
and don't forget to set the reuse identifier in your storyboard

Answer 11

I am getting this error whenever I use reuse Identifer name different than the custom class name
unifid those names solve it for me

Answer 12

I encounter this error, if I put UITapGestureRecognizer in a custom UITableViewCell on the storyboard.(Xcode version is 8.3).

Answer 13

In Swift 5
First I tried registering my UITableViewCell in viewdidload() using class and identifier which I have mentioned below but it did not work for me.
self.tableView.registerClass(MyCustomTableViewCell.self, forCellReuseIdentifier: "customCell")
Solution
Then I registered my UITableViewCell using Nib name and it worked for me
Register your cell in viewdidload() using Nib name
override func viewDidLoad()
{
super.viewDidLoad()
// Do any additional setup after loading the view.
//register your table view cell in Viewdidload() using Nib Name
tableView.register(UINib.init(nibName: "MyCustomTableViewCell", bundle: nil), forCellReuseIdentifier: "customCell")
}