UITableView in Swift - uitableview

Question

I'm struggling to figure out what's wrong with this code snippet. This is currently working in Objective-C, but in Swift this just crashes on the first line of the method. It shows an error message in console log: Bad_Instruction.
func tableView(tableView: UITableView!, cellForRowAtIndexPath indexPath: NSIndexPath!) -> UITableViewCell! {
var cell : UITableViewCell = tableView.dequeueReusableCellWithIdentifier("Cell") as UITableViewCell
if (cell == nil) {
cell = UITableViewCell(style: UITableViewCellStyle.Value1, reuseIdentifier: "Cell")
}
cell.textLabel.text = "TEXT"
cell.detailTextLabel.text = "DETAIL TEXT"
return cell
}

Answer 1

Also see matt's answer which contains the second half of the solution
Let's find a solution without creating custom subclasses or nibs
The real problem is in the fact that Swift distinguishes between objects that can be empty (nil) and objects that can't be empty. If you don't register a nib for your identifier, then dequeueReusableCellWithIdentifier can return nil.
That means we have to declare the variable as optional:
var cell : UITableViewCell?
and we have to cast using as? not as
//variable type is inferred
var cell = tableView.dequeueReusableCellWithIdentifier("CELL") as? UITableViewCell
if cell == nil {
cell = UITableViewCell(style: UITableViewCellStyle.Value1, reuseIdentifier: "CELL")
}
// we know that cell is not empty now so we use ! to force unwrapping but you could also define cell as
// let cell = (tableView.dequeue... as? UITableViewCell) ?? UITableViewCell(style: ...)
cell!.textLabel.text = "Baking Soda"
cell!.detailTextLabel.text = "1/2 cup"
cell!.textLabel.text = "Hello World"
return cell

Answer 2

Sulthan's answer is clever, but the real solution is: don't call dequeueReusableCellWithIdentifier. That was your mistake at the outset.
This method is completely outmoded, and I'm surprised it has not been formally deprecated; no system that can accommodate Swift (iOS 7 or iOS 8) needs it for any purpose whatever.
Instead, call the modern method, dequeueReusableCellWithIdentifier:forIndexPath:. This has the advantage that no optionals are involved; you are guaranteed that a cell will be returned. All the question marks and exclamation marks fall away, you can use let instead of var because the cell's existence is guaranteed, and you're living in a convenient, modern world.
You must, if you're not using a storyboard, register the table for this identifier beforehand, registering either a class or a nib. The conventional place to do that is viewDidLoad, which is as early as the table view exists at all.
Here's an example using a custom cell class:
override func viewDidLoad() {
super.viewDidLoad()
self.tableView.registerClass(MyCell.self, forCellReuseIdentifier: "Cell")
}
// ...
override func tableView(tableView: UITableView!, cellForRowAtIndexPath indexPath: NSIndexPath!) -> UITableViewCell! {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath:indexPath) as MyCell
// no "if" - the cell is guaranteed to exist
// ... do stuff to the cell here ...
cell.textLabel.text = // ... whatever
// ...
return cell
}
But if you're using a storyboard (which most people do), you don't even need to register the table view in viewDidLoad! Just enter the cell identifier in the storyboard and you're good to go with dequeueReusableCellWithIdentifier:forIndexPath:.

Answer 3

#Sulthan's answer is spot on. One possible convenience modification would be to cast the cell as a UITableViewCell!, rather than a UITableViewCell.
func tableView(tableView: UITableView!, cellForRowAtIndexPath indexPath: NSIndexPath!) -> UITableViewCell! {
var cell = tableView.dequeueReusableCellWithIdentifier("CELL") as UITableViewCell!
if !cell {
cell = UITableViewCell(style:.Default, reuseIdentifier: "CELL")
}
// setup cell without force unwrapping it
cell.textLabel.text = "Swift"
return cell
}
Now, you can modify the cell variable without force unwrapping it each time. Use caution when using implicitly unwrapped optionals. You must be certain that the value you are accessing has a value.
For more information, refer to the "Implicitly Unwrapped Optionals" section of The Swift Programming Language.

Answer 4

Try this:
func tableView(tableView: UITableView!, cellForRowAtIndexPath indexPath: NSIndexPath!) -> UITableViewCell! {
let cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as UITableViewCell
cell.textLabel.text = "\(indexPath.row)"
return cell
}
Note that you should register you UITableViewCell and ID when creating instantiating your UITableView:
tableView.delegate = self
tableView.dataSource = self
tableView.registerClass(UITableViewCell.classForCoder(), forCellReuseIdentifier: "Cell")

Answer 5

Here is what I wrote to get it working...
First Register the table view cell with the table view
self.tableView.registerClass(MyTableViewCell.self, forCellReuseIdentifier: "Cell")
Then configure cellForRowAtIndexPath
func tableView(tableView: UITableView!, cellForRowAtIndexPath indexPath: NSIndexPath!) -> UITableViewCell! {
var cell = tableView.dequeueReusableCellWithIdentifier("Cell", forIndexPath: indexPath) as MyTableViewCell
cell.textLabel.text = "Cell Text"
cell.detailTextLabel.text = "Cell Detail Text in Value 1 Style"
return cell
}
I then defined a custom cell subclass write at the bottom of the file (since its so much easier now)
class MyTableViewCell : UITableViewCell {
init(style: UITableViewCellStyle, reuseIdentifier: String!) {
super.init(style: UITableViewCellStyle.Value1, reuseIdentifier: reuseIdentifier)
}
}

Answer 6

Here is a simple way to define table cell in swift 2:
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let identifier = "cell"
let cell = tableView.dequeueReusableCellWithIdentifier(identifier) ??
UITableViewCell.init(style: UITableViewCellStyle.Default, reuseIdentifier: identifier)
cell.textLabel!.text = "my text"
return cell
}
Swift 3:
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
let identifier = "cell"
let cell = tableView.dequeueReusableCell(withIdentifier: identifier) ??
UITableViewCell(style: .default, reuseIdentifier: identifier)
cell.textLabel!.text = "my text"
return cell
}

Answer 7

There's a few answers here, but I don't think any of them are ideal, because after the declaration you're ending up with an optional UITableViewCell, which then needs a cell!... in any declarations. I think this is a better approach (I can confirm this compiles on Xcode 6.1):
var cell:UITableViewCell
if let c = tableView.dequeueReusableCellWithIdentifier("cell") as? UITableViewCell {
cell = c
}
else {
cell = UITableViewCell()
}

Answer 8

Well, I have done this way:
Steps for UITableView using Swift:
Take UITableView in ViewController
Give Referencing Outlets in ViewController.swift class
Give Outlets dataSource & delegate to ViewController
Now Swift code in ViewController.swift class:
class ViewController: UIViewController, UITableViewDelegate, UITableViewDataSource {
#IBOutlet weak var mTableView: UITableView!
var items: [String] = ["Item 1","Item 2","Item 3", "Item 4", "Item 5"]
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view, typically from a nib.
self.mTableView.registerClass(UITableViewCell.self, forCellReuseIdentifier: "cell")
}
override func didReceiveMemoryWarning() {
super.didReceiveMemoryWarning()
// Dispose of any resources that can be recreated.
}
func tableView(tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return self.items.count;
}
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
var cell:UITableViewCell = self.mTableView.dequeueReusableCellWithIdentifier("cell") as! UITableViewCell
cell.textLabel?.text = self.items[indexPath.row]
println(self.items[indexPath.row])
return cell
}
func tableView(tableView: UITableView, didSelectRowAtIndexPath indexPath: NSIndexPath) {
println("You have selected cell #\(indexPath.row)!")
}
}
Now it's time to Run your program.
Done

Answer 9

Actually in the Apple's TableView Guide document and Sample Code you will find the sentence below:
If the dequeueReusableCellWithIdentifier: method asks for a cell that’s defined in a storyboard, the method always returns a valid cell. If there is not a recycled cell waiting to be reused, the method creates a new one using the information in the storyboard itself. This eliminates the need to check the return value for nil and create a cell manually.
So,we could just code like this:
var identifer: String = "myCell"
var cell = tableView.dequeueReusableCellWithIdentifier(identifer) as UITableViewCell
cell.textLabel.text = a[indexPath.row].name
cell.detailTextLabel.text = "detail"
I think this is a suitable way to use tableView

Answer 10

Using "as" keyword would do the following two steps:
1.creating a optional value which wrap a variable of UITableViewCell;
2.unwrapping the optional value.
So,by doing this
var cell : UITableViewCell = tableView.dequeueReusableCellWithIdentifier("Component") as UITableViewCell
you would get a "plain" UITableViewCell type variable: cell.Theoretically speaking, it's ok to do this.But the next line
if (cell == nil) {}
makes trouble, because in swift, only the optional value can be assigned with nil.
So, to solve this problem, you have to make cell a variable of Optional type. just like this:
var cell = tableView.dequeueReusableCellWithIdentifier("Component") as? UITableViewCell
using the keyword "as?" would create a Optional variable, and this, undoubtedly, can be assigned with nil.

Answer 11

For cell template:
func tableView(tableView: UITableView!, cellForRowAtIndexPath indexPath: NSIndexPath!) -> UITableViewCell! {
let myCell : youCell = youCell(style: UITableViewCellStyle.Subtitle, reuseIdentifier: "cell")
return myCell
}

Answer 12

bro, please take a look at the sample https://github.com/brotchie/SwiftTableView

Answer 13

Why not this?
(please delete if i am not in the goal...)
func tableView(tableView: UITableView!, cellForRowAtIndexPath indexPath: NSIndexPath!) -> UITableViewCell! {
if let cell: UITableViewCell = theTableView.dequeueReusableCellWithIdentifier("myCell", forIndexPath: indexPath) as? UITableViewCell {
// cell ok
}else{
// not ok
}
}

Answer 14

I have done in following way: to show detailTextLabel. text value
func tableView(tableView: UITableView, cellForRowAtIndexPath indexPath: NSIndexPath) -> UITableViewCell {
let CellIdentifier: String = "cell"
var cell = tableView.dequeueReusableCellWithIdentifier(CellIdentifier) as? UITableViewCell
if cell == nil {
cell = UITableViewCell(style: UITableViewCellStyle.Value1, reuseIdentifier: CellIdentifier)
}
//cell.accessoryType = UITableViewCellAccessoryType.DisclosureIndicator
// parse the value of records
let dataRecord = self.paymentData[indexPath.row] as! NSDictionary
let receiverName = dataRecord["receiver_name"] as! String
let profession = dataRecord["profession"] as! String
let dateCreated = dataRecord["date_created"] as! String
let payAmount = dataRecord["pay_amount"] as! String
println("payment \(payAmount)")
cell!.textLabel?.text = "\(receiverName)\n\(profession)\n\(dateCreated)"
cell!.detailTextLabel?.text = "$\(payAmount)"
cell!.textLabel?.numberOfLines = 4
return cell!
}// end tableview

Answer 15

UITableView Demo using Playground
//: Playground - noun: a place where people can play
import UIKit
import PlaygroundSupport
class TableviewDemoDelegate:NSObject,UITableViewDataSource,UITableViewDelegate {
func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return 100
}
func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
var cell:UITableViewCell? = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath as IndexPath)
if cell == nil {
cell = UITableViewCell(style: .default, reuseIdentifier: "cell")
}
cell?.textLabel?.text = "Item \(indexPath.row+1)"
return cell!
}
func tableView(_ tableView: UITableView, didSelectRowAt indexPath: IndexPath) {
print("You have selected cell #\(indexPath.row)!")
}
}
var tableView = UITableView(frame:CGRect(x: 0, y: 0, width: 320, height: 568), style: .plain)
tableView.register(UITableViewCell.self, forCellReuseIdentifier: "cell")
let delegate = TableviewDemoDelegate()
tableView.delegate = delegate
tableView.dataSource = delegate
PlaygroundPage.current.liveView = tableView

Answer 16

I went through your codes and most probably the reason for the crash is you are trying to typecast an optional value which is not assigned
Now consider the line of code below
var cell : UITableViewCell = tableView.dequeueReusableCellWithIdentifier("Cell") as UITableViewCell
When there are no cells in the tableview you are still trying to typecast as UITableView.When the compiler tries to typecast nil value you face this issue
The correct statement should be
var cell : UITableViewCell = tableView.dequeueReusableCellWithIdentifier("Cell")
You can use if else statement to typecast for values which holds

Answer 17

Try this code
var cell:CustomTableViewCell = tableView.dequeueReusableCellWithIdentifier("CustomTableViewCell") as CustomTableViewCell
cell.cellTitle.text="vijay"
https://github.com/iappvk/TableView-Swift