Xcode crashing when displaying array in table

Question

I am Getting

fatal error: Index out of range" and "Thread 1: EXC_BAD_INSTRUCTION (code=EXC_I386_INVOP, subcode=0x0)" at line "cell.textLabel?.text = String(arrayTable[indexPath.row])

When I test my function in playground it works as expected. My array get populated. So, I don't understand why Xcode won't find any value in my array.

any idea?

class ViewController: UIViewController, UITableViewDataSource, UITableViewDelegate {

@IBOutlet weak var slider: UISlider!

@IBAction func sliderSelector(_ sender: Any) {
   arrayTable = [Int]()
    tableGenerate()
}

var arrayTable = [Int]()


public func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
    return 50
}

public func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
    let cell = UITableViewCell(style:UITableViewCellStyle.default, reuseIdentifier: "Cell")
    cell.textLabel?.text = String(arrayTable[indexPath.row])
    return cell
}

func tableGenerate () {
    var tableMultiplier = 1
    while tableMultiplier <= 50 {
        arrayTable.append(tableMultiplier * Int(slider.value))
        tableMultiplier += 1
    }

}

fatal error: Index out of range Means numberOfRowsInSection not sync with cellForRowAtIndexPath with your array count. — Mathi Arasan
– Mathi Arasan, Commented Aug 17, 2017 at 10:35
as suggested below, changing return 50 to return arrayTable.count fixed the crash — Dev0urCode
– Dev0urCode, Commented Aug 17, 2017 at 11:25

pacification · Accepted Answer · 2017-08-17 10:32:37Z

2

Pretty common mistake for newbies is to return from numberOfRowsInSection any magic number. Instead of that you should return your real items count: return arrayTable.count and i believe all should work fine.

answered Aug 17, 2017 at 10:32

pacification

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8 Comments

Divyesh Gondaliya Over a year ago

but the after initialize array the tablview not update so u should to reload its data

Dev0urCode Over a year ago

it fixed the crash but the table does not display the array, looking for that now, @DivyeshGondaliya do you know how to reload ?

Divyesh Gondaliya Over a year ago

check my answer @Dev0urCode

Dev0urCode Over a year ago

I did but I'm sorry I do not understand where you mean to reload ?

pacification Over a year ago

@Dev0urCode just call tableView.reloadData().

|

Divyesh Gondaliya · Accepted Answer · 2017-08-17 13:31:38Z

1

Try to make changes like this

 public func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return arrayTable.count
    }

    func tableGenerate () {
        var tableMultiplier = 1
        while tableMultiplier <= 50 {
            arrayTable.append(tableMultiplier * Int(slider.value))
            tableMultiplier += 1
        }
      DispatchQueue.main.async {
         print(arrayTable)
         tblview.reloadData()
      }
    }

edited Aug 17, 2017 at 13:31

answered Aug 17, 2017 at 10:33

Divyesh Gondaliya

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16 Comments

Divyesh Gondaliya Over a year ago

create your tableview object first and then reload it here its working and also check that your tableview datasource or delegate given or not @Dev0urCode

Dev0urCode Over a year ago

I write what you suggested but I get "Ambiguous reference to member 'tableView(_:numberOfRowsInSection:)'" I also did put the tableGenerate function after the tableView functions

Divyesh Gondaliya Over a year ago

youtube.com/watch?v=I4jSwWmqfOA watch this and get note where you not doing well @Dev0urCode

Dev0urCode Over a year ago

I can't see any tableView.reloadData () anywhere in the video :(

Divyesh Gondaliya Over a year ago

just watch you give delegate datasource method to your viewcontroller or not or how to create object of tableview @Dev0urCode

|

nomadoda · Accepted Answer · 2017-08-17 10:43:50Z

0

When the view loads, your tableView will attempt to return 50 cells. For each cell you're trying to assign the textlabel text to:

cell.textLabel?.text = String(arrayTable[indexPath.row])

But because the arrayTable is empty when the view loads, the application crashes when it's trying to access an index by indexPath.row.

answered Aug 17, 2017 at 10:43

nomadoda

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Comments

Abdul Waheed · Accepted Answer · 2017-08-17 11:44:36Z

0

problem in this method

public func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
return yourArray.count
}

answered Aug 17, 2017 at 11:44

Abdul Waheed

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