how to get indexpath of tableView in any method - ios

Question

I'm trying to show animation if the indexPath == 0 and scroll direction is downward, but I'm unable to get the indexPath of tableView in scrollViewdidScroll method. here's my code -->
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let indexPath = tableView.indexPath(for: ThirdTableViewCell() as UITableViewCell)
if (self.lastContentOffset > scrollView.contentOffset.y) && indexPath?.row == 0 {
print ("up")
}
else if (self.lastContentOffset < scrollView.contentOffset.y) {
// print ("down")
}
self.lastContentOffset = scrollView.contentOffset.y
}
I got the indexPath nil while debugging

Answer 1

You still haven't explained what you really want to do, but maybe this will help...
Start by setting up your scrollViewDidScroll like this:
func scrollViewDidScroll(_ scrollView: UIScrollView) {
var partOfRowZeroIsVisible: Bool = false
var topOfRowZeroIsVisible: Bool = false
var userIsDraggingDown: Bool = false
// if user pulls table DOWN when Row Zero is at top,
// contentOffset.y will be negative and table will
// bounce back up...
// so, we make y AT LEAST 0.0
let y = max(0.0, tableView.contentOffset.y)
// point for the top visible content
let pt: CGPoint = CGPoint(x: 0, y: y)
if let idx = tableView.indexPathForRow(at: pt), idx.row == 0 {
// At least PART of Row Zero is visible...
partOfRowZeroIsVisible = true
} else {
// Row Zero is NOT visible...
partOfRowZeroIsVisible = false
}
if y == 0 {
// Table view is scrolled all the way to the top...
topOfRowZeroIsVisible = true
} else {
// Table view is NOT scrolled all the way to the top...
topOfRowZeroIsVisible = false
}
if (self.lastContentOffset >= y) {
// User is DRAGGING the table DOWN
userIsDraggingDown = true
} else {
// User is DRAGGING the table UP
userIsDraggingDown = false
}
// save current offset
self.lastContentOffset = y
Then, to show or hide your "arrow":
// if you want to show your "arrow"
// when ANY PART of Row Zero is visible
if partOfRowZeroIsVisible {
arrow.isHidden = false
} else {
arrow.isHidden = true
}
or:
// if you want to show your "arrow"
// ONLY when table view has been scrolled ALL THE WAY to the top
if topOfRowZeroIsVisible {
arrow.isHidden = false
} else {
arrow.isHidden = true
}
or:
// if you want to show your "arrow"
// when ANY PART of Row Zero is visible
// and
// ONLY if the user is dragging DOWN
if partOfRowZeroIsVisible && userIsDraggingDown {
arrow.isHidden = false
} else {
arrow.isHidden = true
}
or:
// if you want to show your "arrow"
// ONLY when table view has been scrolled ALL THE WAY to the top
// and
// ONLY if the user is dragging DOWN
if topOfRowZeroIsVisible && userIsDraggingDown {
arrow.isHidden = false
} else {
arrow.isHidden = true
}