how can I trim my UITableViewController so that it shows always only 10 last rows? - swift

Question

Currently in my Swift app I have a UITableViewController. I already implemented paging when user scrolls to the top of the table - it loads more data and fills the table there.
But now I want to apply also the other feature - when user scroll to the very bottom of the table, it should truncate rows that added before thanks to paging and leave only last 10 cells.
So far my code looks like this:
override func tableView(_ tview: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
if indexPath.row == 0 { // first cell
print("this is first cell - it works")
loadMoreItems()
}
if indexPath.row == messages.count - 1 { // last cell
if(self.messages.count > 10){
leaveTenVisibleMessages()
}
}
let cell = tview.dequeueReusableCell(withIdentifier: "chat") as! SingleCommentCell
let msg = self.messages[indexPath.row]
.
.
.
and the method leaveTenVisibleMessages looks as follows (so far):
func leaveTenVisibleMessages(){
print("last cell before \(self.messages.count)")
if(self.messages.count > 10){
self.messages = Array(self.messages.suffix(10))
}
print("last cell after \(self.messages.count)")
//tview.reloadData()
}
however, even though I see that trimming the array worked:
last cell before 11
last cell after 10
I'm constantly getting error:
fatal error: Index out of range
I think the reason is that cellforrow at the moment of runtime expects more than 10 entries in array messages. How can I refresh only 10 rows then?
I just checked and the problem is this line:
let msg = self.messages[indexPath.row]
e.g. my code refers to the indexPath.row = 29 and messages array has only 10 records

Answer 1

Check your code that returns the numberOfRowsInSection.
e.g.
func tableView(
_ tableView: UITableView,
numberOfRowsInSection section: Int) -> Int
{
let result = self.messages.count
NSLog("numberOfRowsInSection = %d", result)
return result
}