Deleting a Row from a UITableView in Swift?

Question

I have a table of names and I am making a swipe and delete function for them which removes them from a names variable which is an array.

I selected the functions which most closely resembled the tutorial inside xcode and filled them out, but my app crashes randomly when I click the delete button. Here is my code for the delete button:

func tableView(_ tableView: UITableView, editActionsForRowAt indexPath: IndexPath) -> [UITableViewRowAction]? {
    let deleteAction = UITableViewRowAction(style: .destructive, title: "Delete") { (rowAction: UITableViewRowAction, indexPath: IndexPath) -> Void in
        print("Deleted")
        self.catNames.remove(at: indexPath.row)
        self.tableView.deleteRows(at: [indexPath], with: UITableViewRowAnimation.automatic)
        self.tableView.reloadData()
    }
}

I'm new to coding and learning swift, I am following a tutorial for swift 2 and working with swift 3 so there are a few issues I have when following along, this being one I'm properly stuck on.

FYI - whenever you post a question about a crash, you must include relevant details about the crash including the exact line causing the crash and the complete error message. — rmaddy, Oct 20 '16 at 14:03
Removing the `reloadData` call will not fix the issue. Look at the answers below. — Phil Hudson, Oct 20 '16 at 14:04
@PhilHudson There is no need to call `reloadData` when the OP is already correctly calling `deleteRows`. And until the OP posts details about the crash, there is no way to know for sure what the complete solution may be. — rmaddy, Oct 20 '16 at 14:13
@maddy just by looking at the code, you can see where the bug is. Sure it should have provided the crash log but what you're suggesting is best practice not the actual root cause. — Phil Hudson, Oct 20 '16 at 14:15

ronatory · Accepted Answer · 2017-10-12T19:53:00.943

132

Works for Swift 3 and Swift 4

Use the UITableViewDataSource tableView(:commit:forRowAt:) method, see also this answer here:

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
  if editingStyle == .delete {
    print("Deleted")

    self.catNames.remove(at: indexPath.row)
    self.tableView.deleteRows(at: [indexPath], with: .automatic)
  }
}

edited Oct 12 '17 at 19:53

answered Oct 20 '16 at 13:54

ronatory

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25

No, do not call `reloadData` just to delete one row. This is a bad practice. – rmaddy Oct 20 '16 at 14:01
2

You are right @rmaddy! Updated the answer and wanted to link it to the other answer which mentioned it before, but the on deleted it unfortunately – ronatory Oct 20 '16 at 14:10
3

There is no reason to use `begin/endUpdates` around a single change to a table view. – rmaddy Oct 20 '16 at 14:12
@rmaddy Thanks for the info – ronatory Oct 20 '16 at 14:17
worth noting that this should be called on the main thread otherwise you might get funky outcomes – Joe Williams Nov 25 '17 at 02:23
What is the aim of implementing this tableViewcomitEditingStyle method as it is for older iOS versions, and not needed while implementing editActionsForRowAt – Michał Ziobro Mar 14 '18 at 09:18
I get `Cannot use mutating member on immutable value: 'myList' is a get-only property` (`myList` being `catNames` in this post). – May 06 '18 at 00:05
how to show delete option on hold of cell like whatsapp message in ios swift – Dilip Tiwari Jul 20 '18 at 11:41

score 28 · Answer 2 · edited Jan 22 '18 at 13:39

28

First you need to add this function

func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
    return true 
}

then your function is ok but no need of tableview reload data just call tableview.beingUpdates and tableview.endUpdates

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
    if editingStyle == .delete {
       print("Deleted")
       self.catNames.remove(at: indexPath.row)
       self.tableView.beginUpdates()
       self.tableView.deleteRows(at: [indexPath], with: .automatic)
       self.tableView.endUpdates() 
    }
}

edited Jan 22 '18 at 13:39

Luca Davanzo

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answered Oct 20 '16 at 13:55

ivan123

317
2
7

1

This is the default and adding this won't solve whatever crash the OP is having. – rmaddy Oct 20 '16 at 14:02
3

There is no reason to use begin/endUpdates around a single change to a table view. – rmaddy Oct 20 '16 at 14:19

score 9 · Answer 3 · answered Nov 03 '17 at 12:22

In Swift 4 Try This

func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool {
        return true
    }
    func tableView(_ tableView: UITableView, commit editingStyle:   UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
        if (editingStyle == .delete) {
            arrStudentName.remove(at: indexPath.row)
            tableView.beginUpdates()
            tableView.deleteRows(at: [indexPath], with: .middle)
            tableView.endUpdates()
        }
    }

It is always a good idea to mention what protocol these methods are part of. In this case it is UITableViewDataSource for both methods. — rommex, Jan 31 '19 at 19:08

score 3 · Answer 4 · edited May 24 '17 at 07:47

3

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {

    if editingStyle == .delete {

        self.animals.remove(at: indexPath.row)

        self.dataDisplayTbleView.reloadData()
    }

}

edited May 24 '17 at 07:47

Arya McCarthy

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answered May 24 '17 at 07:27

suri

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5

Shouldn't call reload data when it's only a single cell. This will mess up the table animations. – Justin Meiners Jun 16 '22 at 17:45

score 2 · Answer 5 · answered Feb 05 '18 at 06:58

**

for swift 3

**

  func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath) {
      if editingStyle == .delete {
        print("Deleted")

        self.catNames.remove(at: indexPath.row)
        self.tableView.deleteRows(at: [indexPath], with: .automatic)
      }
    }

score 0 · Answer 6 · answered Oct 20 '16 at 17:12

0

My answer for you

func tableView(_ tableView: UITableView, canEditRowAt indexPath: IndexPath) -> Bool
{
     return true
}

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCellEditingStyle, forRowAt indexPath: IndexPath)
{
    if editingStyle == .delete
    {
        array.remove(at: indexPath.row)
        tblDltRow.reloadData()
    }
}

You need to refresh the table

answered Oct 20 '16 at 17:12

user3182143

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According to @rmaddy from another answer reloading for just a removed element is a bad practice. instead of reloading It should be something like self.tableView.deleteRows(at: [indexPath], with: .automatic). You really dont know how the cell works or is defined. Imagine a long list with a complex custom Cell maybe with images, a reload could force downloading or trigger – le0diaz Apr 04 '17 at 17:09
@le0diaz, Actually today I got the issue I have the tableview in which we are showing the user lists and there there is delete button in every cell. If I delete the first row, it will delete the first row from table view but if I delete the 10 row after deleting the first row. Delete button will have wrong index and it is deleting the row from tableview. – Mandeep Singh Aug 01 '18 at 08:35
Hi Possible can I ask question related to moveRow ? – Feb 26 '20 at 10:54
@le0diaz same issue here. How did you fix it? I am calling delete function from the cell using delegates. – Yessen Yermukhanbet Jul 05 '21 at 16:33

score 0 · Answer 7 · answered Jun 07 '20 at 21:33

You don't have to reload the tableView.

Before you use tableView.deleteRows(at: [IndexPath], with: UITableView.RowAnimation) you must substrate the number of rows you want delete in numberOfRowsInSection

    override func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {

return //Your current number of rows - The number of rows to delete

    }

Normally the number of rows is the number of Items from an array (yourArray.count), that means you can delete the items from this array before you delete the cells and you get the same result.

score -1 · Answer 8 · answered Jun 18 '19 at 19:03

-1

    self.tableView.beginUpdates()
    self.tableView.deleteRows(at: [ IndexPath(row: index, section: section) ], with: .fade)
    self.remove_object_from_model()
    self.tableView.endUpdates()

answered Jun 18 '19 at 19:03

Lee Irvine

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beginUpdates and endUpdates will be deprecated in a future release. – Nike Kov Sep 03 '19 at 14:24

score -1 · Answer 9 · answered Feb 18 '21 at 15:27

For Swift 5

func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
      if editingStyle == .delete {
        print("Deleted")

        self.catNames.remove(at: indexPath.row)
        self.tableView.deleteRows(at: [indexPath], with: .automatic)
      }
    }

Deleting a Row from a UITableView in Swift?

9 Answers9

for swift 3

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