UITableView - scroll to the top

Question

In my table view I have to scroll to the top. But I cannot guarantee that the first object is going to be section 0, row 0. May be that my table view will start from section

Answer 1

I had to add the multiply by -1 * to the sum of the status bar and the navigation bar, because it was going that height off the screen,

self.tableView.setContentOffset(CGPointMake(0 , -1 * 
  (self.navigationController!.navigationBar.height +  
  UIApplication.sharedApplication().statusBarFrame.height) ), animated:true)

Answer 2

It's better to not use NSIndexPath (empty table), nor assume that top point is CGPointZero (content insets), that's what I use -

[tableView setContentOffset:CGPointMake(0.0f, -tableView.contentInset.top) animated:YES];

Hope this helps.

Answer 3

I use tabBarController and i have a few section in my tableview at every tab, so this is best solution for me.

extension UITableView {

    func scrollToTop(){

        for index in 0...numberOfSections - 1 {
            if numberOfSections > 0 && numberOfRows(inSection: index) > 0 {
                scrollToRow(at: IndexPath(row: 0, section: index), at: .top, animated: true)
                break
            }

            if index == numberOfSections - 1 {
                setContentOffset(.zero, animated: true)
                break
            }
        }

    }

}

Answer 4

I've encountered an issue calling trying some of the methods on an empty tableView. Here's another option for Swift 4 that handles empty tableviews.

extension UITableView {
  func hasRowAtIndexPath(indexPath: IndexPath) -> Bool {
    return indexPath.section < self.numberOfSections && indexPath.row < self.numberOfRows(inSection: indexPath.section)
  }

  func scrollToTop(animated: Bool) {
    let indexPath = IndexPath(row: 0, section: 0)
    if self.hasRowAtIndexPath(indexPath: indexPath) {
      self.scrollToRow(at: indexPath, at: .top, animated: animated)
    }
  }
}

Usage:

// from yourViewController or yourTableViewController
tableView.scrollToTop(animated: true)//or false

Answer 5

using contentOffset is not the right way. this would be better as it is table view's natural way

tableView.scrollToRow(at: NSIndexPath.init(row: 0, section: 0) as IndexPath, at: .top, animated: true)

Answer 6

Note: This answer isn't valid for iOS 11 and later.

I prefer

[mainTableView setContentOffset:CGPointZero animated:YES];

If you have a top inset on your table view, you have to subtract it:

[mainTableView setContentOffset:CGPointMake(0.0f, -mainTableView.contentInset.top) animated:YES];