UITextField in custom UITableViewCell unexpectedly found nil

Question

I have a TableView with custom cells that have a TextField inside, unfortunately I get a Thread 1: Fatal error: Unexpectedly found nil while un

Answer 1

Everywhere where you use WalletTableViewCell() you are creating a new instance of the WalletTableViewCell. The crash happens because you are creating it programmatically, while WalletTableViewCell was designed using storyboards, and since you did not instantiated it using storyboards, @IBOutlets have not been set, therefore are nil.

Update

Try to fix it using this. Update CryptoCellDelegate to this:

protocol CryptoCellDelegate {
    func cellAmountEntered(_ walletTableViewCell: WalletTableViewCell)
}

Then in WalletTableViewCell update amountTextFieldEntered to:

@IBAction func amountTextFieldEntered(_ sender: Any) {
    delegate?.cellAmountEntered(self)
}

And finally update delegate implementation:

extension WalletTableViewController: CryptoCellDelegate {
    func cellAmountEntered(_ walletTableViewCell: WalletTableViewCell) {
        // now you can use walletTableViewCell to access the cell that called the delegate method
        if walletTableViewCell.amountTextField.text == "" {
            return
        }
        let str = walletTableViewCell.amountTextField.text

        let formatter = NumberFormatter()
        formatter.locale = Locale(identifier: "en_US")
        let dNumber = formatter.number(from: str!)
        let nDouble = dNumber!
        let eNumber = Double(truncating: nDouble)

        walletTableViewCell.amountLabel.text = String(format:"%.8f", eNumber)

        UserDefaults.standard.set(walletTableViewCell.amountLabel.text, forKey: "bitcoinAmount")
        walletTableViewCell.amountTextField.text = ""

    }
}