Inserting a table view row data from another table view? - swift

Question

So I have two table views. MainTableView and SecondaryTableView, The MainTableView has empty rows with no text. A Table view cell is configured though. These rows have the option to delete. The SecondaryTableView rows also have an editing style in which I am using to ADD the selected row into the MainTableView rows.
class MainVC: UIViewController,UITableViewDataSource,UITableViewDelegate {
#IBOutlet var mycartableview: UITableView!
var passedcar = String()
override func viewDidLoad() {
super.viewDidLoad()
mycartableview.tableFooterView = UIView(frame: CGRect.zero)
}
var diynames: [String] = ["a","b","c"]
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return diynames.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let diyname = diynames[indexPath.row]
let cell = tableView.dequeueReusableCell(withIdentifier: "mycarcell") as! mycarcell
cell.mycartitle.text = diyname
return cell
}
func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
return true
}
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete{
diynames.remove(at: indexPath.row)
tableView.beginUpdates()
tableView.deleteRows(at: [indexPath], with: .fade)
tableView.endUpdates()
}
}
SecondaryVC code:
class MainVC: UIViewController, UITableViewDelegate, UITableViewDataSource{
let names = ["aa","ba","ca","da","ea",]
#IBOutlet var tableview: UITableView!
#IBOutlet var slctedcar: UILabel!
override func viewDidLoad() {
super.viewDidLoad()
self.tableview.backgroundColor = .white
// Do any additional setup after loading the view.
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return names.count
return names.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let cell = tableView.dequeueReusableCell(withIdentifier: "diylistcell") as! diylistcellTableViewCell
cell.diytitle.text = names[indexPath.row]
return cell
}
func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
return true
}
func tableView(_ tableView: UITableView, editActionsForRowAt indexPath: IndexPath) -> [UITableViewRowAction]? {
let addbutton = UITableViewRowAction(style: .normal, title: "Add") { (rowAction, indexpath
) in
print("Add clicked")
let mycarvc = MyCarViewController()
mycarvc.diynames.append(contentsOf: self.hcdiynames)
let hcindexpath = IndexPath(row: mycarvc.diynames.count - 1, section: 0)
mycarvc.mycartableview.insertRows(at: [hcindexpath], with: .automatic) //this is where the error occurs. Thread 1: Fatal error: Unexpectedly found nil while implicitly unwrapping an Optional value
mycarvc.mycartableview.endUpdates()
}
addbutton.backgroundColor = UIColor.darkGray
return [addbutton]
}
Clear Image of Error
That's where my pain is coming from. As you could see in the picture above the highlighted area it says that my array coming from the main vc is a count of 8. That checks out completely because the original array has 3 and I am appending 5 new ones. The error implicitly found nil has left me clueless in this scenario. If anybody has any suggestions on how to fix this problem it would be highly appreciated, thank you .

Answer 1

This is a common error when you try to transfer data between VC , I usually create 1 variable which will store what I want and after in the viewDidLoad() I give the value of this variable to what I really want , IN your code the equivalent is
class MainVC: UIViewController,UITableViewDataSource,UITableViewDelegate {
#IBOutlet var mycartableview: UITableView!
var passedcar = String()
// I JUST CREATED THE VARIABLE WHICH WILL HOLD OUR VALUES
var diynamesContainer = [String]()
///////////////////
var diynames: [String] = ["a","b","c"]
override func viewDidLoad() {
super.viewDidLoad()
mycartableview.tableFooterView = UIView(frame: CGRect.zero)
// I ADD TO OUR ARRAY THE VALUE OF THE diynamesContainer
diynames.append(contentsOf: diynamesContainer)
//////////////////
}
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return diynames.count
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let diyname = diynames[indexPath.row]
let cell = tableView.dequeueReusableCell(withIdentifier: "mycarcell") as! mycarcell
cell.mycartitle.text = diyname
return cell
}
func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
return true
}
func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
if editingStyle == .delete{
diynames.remove(at: indexPath.row)
tableView.beginUpdates()
tableView.deleteRows(at: [indexPath], with: .fade)
tableView.endUpdates()
}
}
/*
// MARK: - Navigation
and in our main vc you replace
let mycarvc = MyCarViewController()
mycarvc.diynames.append(contentsOf: self.hcdiynames)
by
let mycarvc = MyCarViewController()
mycarvc.diynamesContainer = self.hcdiynames
Try to run your code, the error will go away