CODEWITHSUNDEEP
iosswiftuitableview
iOSGeek
iOSGeek

Reputation: 5577

Crash with Missing cell for newly visible row when updating UITableView

I am experiencing a crash when I delete a row.

// Updating my data model 
....
// apply the updates
self.tableView.beginUpdates()
self.tableView.deleteRows(at: indexPathsToDelete, with: .automatic)
self.tableView.endUpdates()

Steps to reproduce - Add rows - Delete rows, specifically making sure there's some rows outside the current screen (that will then be in screen when the deletion is successful - Repeat until crash occurs

It doesn't always happen so my best guess is that it will happen only when the cells it's trying to load get recycled

This is in 10.0 simulator with Xcode 8.0

  *** Assertion failure in -[UITableView _updateWithItems:updateSupport:],
 /BuildRoot/Library/Caches/com.apple.xbs/Sources/UIKit_Sim/UIKit-3599.6/UITableView.m:3149
 Missing cell for newly visible row 2
 (null)

code for cellForRowAt

if isMultipe{
   let cell =  tableView.dequeueReusableCell(withIdentifier: DetailsTableViewCell.defaultIdentifier, for: indexPath) as! DetailsTableViewCell
return cell
    } else {
let cell =  tableView.dequeueReusableCell(withIdentifier: DetailsMultipleTableViewCell.defaultIdentifier, for: indexPath) as! DetailsMultipleTableViewCell
   return cell
}

the same bug reported here : https://forums.developer.apple.com/thread/49676

Upvotes: 19

Views: 5138

Answers (7)

Klaas
Klaas

Reputation: 22763

In my case this happened when I forgot to call super.prepareForReuse() in my custom subclass.

See https://developer.apple.com/documentation/uikit/uitableviewcell/1623223-prepareforreuse:

If you override this method, you must be sure to invoke the superclass implementation.

Upvotes: 0

Bohdan Savych
Bohdan Savych

Reputation: 3447

This problem happened to me when I had cells with different sizes. My code: 

tableView.estimatedRowHeight = 150
tableView.rowHeight = UITableViewAutomaticDimension

During moving/inserting/deleting, app was crashing with "Missing cell for newly visible row" message. So I removed this line: 

tableView.estimatedRowHeight = 150

and implement delegate method in which returned separate estimated height for each row.

func tableView(_ tableView: UITableView, estimatedHeightForRowAt indexPath: IndexPath) -> CGFloat {}

Hope it will help someone.

Upvotes: 1

Gerd Castan
Gerd Castan

Reputation: 6849

I had a similar problem.

emrekyv suggested to delete estimatedSectionHeaderHeight but I have a table with one seaction and no header and no footer.

Expanding his idea and setting estimatedRowHeight to 0 (= not automatic) fixed the problem.

So the rule is:

Do not estimate any height when updating a UITableView.

Upvotes: 0

Mohammed
Mohammed

Reputation: 136

In my case I had this issue just for inserting the first row to an empty section, so I tried to fix it like this:

self.array.append(item)
if self.array.count > 1 {
    self.tableView.beginUpdates()
    self.tableView.insertRows(at: indexPathes, with: .top)
    self.tableView.endUpdates()
} else {
    self.tableView.reloadSections([1], with: .fade)
}

Upvotes: 1

Andrey Zhukov
Andrey Zhukov

Reputation: 71

In my case it was crashing when cells have used autolayout for calculating it's height. So, the only guaranteed solution is use manual calculating heights. (what is actually sad..)

Upvotes: 1

emrekyv
emrekyv

Reputation: 1266

I had the same problem and I found out that UITableView has serious problems with animating insert/update/delete rows when section headers are variable height. Just convert the height to some constant and try it again.

This actually means deleting estimatedSectionHeaderHeight.

Upvotes: 8

Vladimir Prigarin
Vladimir Prigarin

Reputation: 474

Remove indexPath in tableView.dequeueReusableCell

if isMultipe{
   let cell =  tableView.dequeueReusableCell(withIdentifier: DetailsTableViewCell.defaultIdentifier) as! DetailsTableViewCell
return cell
    } else {
let cell =  tableView.dequeueReusableCell(withIdentifier: DetailsMultipleTableViewCell.defaultIdentifier) as! DetailsMultipleTableViewCell
   return cell
}

Upvotes: 0

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