UITableView , Scroll to bottom on reload?

Question

I have a UITableView with cells that are dynamically updated. Everything works fine apart from when tableview.reload is called (see below) to refresh the cells in the table I would like the table to scroll to the bottom to show the new entries.

- (void)reloadTable:(NSNotification *)notification {
    NSLog(@"RELOAD TABLE ...");
    [customTableView reloadData];
    // Scroll to bottom of UITable here ....
}

I was planning to use scrollToRowAtIndexPath:atScrollPosition:animated: but then noticed that I don't have access to an indexPath.

Does anyone know how to do this, or of a delegate callback that I could use?

Similar to [link](http://stackoverflow.com/questions/2156614/how-to-start-uitableview-on-the-last-cell). Apparently, the trick there was to call `numberOfRowsInSection:`. — Andrei Stanescu, Feb 25 '11 at 01:07

score 123 · Accepted Answer · edited Nov 19 '13 at 13:06

123

Use:

NSIndexPath* ipath = [NSIndexPath indexPathForRow: cells_count-1 inSection: sections_count-1];
[tableView scrollToRowAtIndexPath: ipath atScrollPosition: UITableViewScrollPositionTop animated: YES];

Or you can specify the section index manually (If one section => index=0).

edited Nov 19 '13 at 13:06

Dilip Manek

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answered Feb 25 '11 at 00:47

Max

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I don't think [customTableView reloadData] is a blocking call. If that code is copy-pasted right after the reloadData it will generate an exception since there is no real data at that moment. I will test this. – Andrei Stanescu Feb 25 '11 at 00:55
2

No it won't crash - reloadData is synchronous – Max Feb 25 '11 at 01:00
4

To scroll to the bottom use UITableViewScrollPositionBottom – orkoden May 30 '13 at 07:59
1

@Max Why not use setContentOffset ? – onmyway133 Jan 15 '14 at 10:27
1

Bad stuff happens if `cells_count` is 0 – user102008 Jan 25 '14 at 02:37
1

Note that this method may not work when you have set estimatedRowHeight to non-zero value. You need to disable estimatedRowHeight to get it works. – Oscar Jun 26 '15 at 14:02

score 41 · Answer 2 · answered Feb 10 '15 at 15:16

41

Another solution is to flip the table vertically, and flip each cell vertically:

Apply the transform to the UITableView when initializing:

tableview.transform = CGAffineTransformMakeScale(1, -1);

and in cellForRowAtIndexPath:

cell.transform = CGAffineTransformMakeScale(1, -1);

This way you don't need workarounds for scrolling issues, but you will need to think a little harder about contentInsets/contentOffsets and header/footer interactions.

answered Feb 10 '15 at 15:16

Michael Wilson

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This is hacky, but its so much more visually appealing than the other solutions! – David Wong Sep 10 '15 at 06:49
You are genius! best way to do this. So elegant. – Faruk Dec 21 '15 at 22:21
I hate to say it but this hack works better then all other methods. – SpaceTrucker Apr 13 '16 at 23:17
4

SlackViewController uses this technique :) – aryaxt Apr 19 '16 at 18:21
@michael-wilson please please please tell us why this even works. – George Maisuradze Jan 08 '17 at 13:44
4

This is indeed a brilliant solution! It's not that difficult to see why this works. @GeorgeMaisuradze the first transform flips the whole tableview up-side down. So all cells are actually unreadable since it's up-side down. But without the cell transform you can already see that since the tableview is upside-down any pull-to-refresh would be at the bottom and you can use scrollToTop to easily scroll to the bottom: [self.tableView setContentOffset:CGPointZero animated:animated]; Then simply use the flip-transform on the cells again to make them readable. Brilliant! – Bob de Graaf Mar 24 '17 at 08:55
Awesome . Just FYI. You'll need to swap your header with footer and flip the views too ;) – Sourav Chandra Apr 27 '17 at 05:16
Unfortunately, footer is showing on the top :(.which is basically a big empty space. – coolly Nov 08 '17 at 16:33
Wow, I spent 2 days trying to create smooth scrolling and loading previous data when the scroll approaches top. Finally found this post and this solution totally changed my approach. Now everything works so smooth that I would give 100 pluses to you Mr. Michael Wilson. Thanks! – Art Feb 04 '18 at 19:39

score 34 · Answer 3 · answered Aug 16 '13 at 00:55

34

-(void)scrollToBottom{

        [self.tableView scrollRectToVisible:CGRectMake(0, self.tableView.contentSize.height - self.tableView.bounds.size.height, self.tableView.bounds.size.width, self.tableView.bounds.size.height) animated:YES];

}

answered Aug 16 '13 at 00:55

mkral

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This seems to be a better solution for a general case of scrolling to the bottom. If the contents of your tableview change, or you've deallocated the table when you attempt to scroll, cells_count will probably be 0 and you may run into some issues. Scrolling to the end of the table by it's size may be slightly more robust. I'll be using this moving forward. Admittedly, the question doesn't require this. – Roderic Campbell Apr 15 '14 at 22:23
Great job boss... Thanks! – Anand Gautam Sep 05 '14 at 15:30

score 10 · Answer 4 · answered Sep 23 '14 at 01:49

//In swift 

var iPath = NSIndexPath(forRow: self.tableView.numberOfRowsInSection(0)-1, 
                        inSection: self.tableView.numberOfSections()-1)
self.tableView.scrollToRowAtIndexPath(iPath, 
                                      atScrollPosition: UITableViewScrollPosition.Bottom,                     
                                      animated: true)

score 8 · Answer 5 · answered May 16 '18 at 17:36

8

Swift 3

For all the folks here trying to figure out how to solve this problem the key is to call the .layoutIfNeeded() method after .reloadData() :

tableView.reloadData()
tableView.layoutIfNeeded()
tableView.setContentOffset(CGPoint(x: 0, y: tableView.contentSize.height - tableView.frame.height), animated: false)

I was working with multiple sections in UITableView and it worked well.

answered May 16 '18 at 17:36

Chris Tsitsaris

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Thank you. It is the most valuable answer for the case when autolayout is used. There are plenty of possibilities to perform scroll and calculate offset, but they are of no help because layout is not updated yet, when setContentOffset called. And call .layoutIfNeeded() resolves this problem. – Vladimir Aug 11 '20 at 15:38
This actually works if number of rows changes :) thanks – Matej Ukmar Feb 02 '21 at 18:48

score 8 · Answer 6 · answered Aug 30 '19 at 06:29

Fot Swift 5

extension UITableView {
    func scrollToBottom(animated: Bool = true) {
        let section = self.numberOfSections
        if section > 0 {
            let row = self.numberOfRows(inSection: section - 1)
            if row > 0 {

                self.scrollToRow(at: IndexPath(row: row-1, section: section-1), at: .bottom, animated: animated)
            }
        }
    }
}

jfgrang · Answer 7 · 2016-01-20T09:25:41.967

As this is something you might want to use really often, I suggest that you create a class extension on UITableView :

extension UITableView {
    func scrollToBottom(animated: Bool = true) {
        let section = self.numberOfSections
        if section > 0 {
            let row = self.numberOfRowsInSection(section - 1)
            if row > 0 {
                self.scrollToRowAtIndexPath(NSIndexPath(forRow: row - 1, inSection: section - 1), atScrollPosition: .Bottom, animated: animated)
            }
        }
    }
}

score 5 · Answer 8 · answered Jun 29 '13 at 11:20

This is another solution, worked well in my case, when cell height is big.

- (void)scrollToBottom
{
    CGPoint bottomOffset = CGPointMake(0, _bubbleTable.contentSize.height - _bubbleTable.bounds.size.height);
    if ( bottomOffset.y > 0 ) {
        [_bubbleTable setContentOffset:bottomOffset animated:YES];
    }
}

score 1 · Answer 9 · answered Apr 19 '16 at 18:15

extension is better to be done on UIScrollView instead of UITableView, this way it works on scrollView, tableView, collectionView (vertical), UIWebView (inner scroll view), etc

public extension UIScrollView {

    public func scrollToBottom(animated animated: Bool) {
        let rect = CGRectMake(0, contentSize.height - bounds.size.height, bounds.size.width, bounds.size.height)
        scrollRectToVisible(rect, animated: animated)
    }

}

score 1 · Answer 10 · answered Jun 29 '19 at 03:07

Swift 5

    func scrollToBottom() {
        let section = self.tableView.numberOfSections
        let row = self.tableView.numberOfRows(inSection: self.tableView.numberOfSections - 1) - 1;
        guard (section > 0) && (row > 0) else{ // check bounds
            return
        }
        let indexPath = IndexPath(row: row-1, section: section-1)
        self.tableView.scrollToRow(at: indexPath, at: .top, animated: true)
    }

I dont agree that we should user cells_count,sections_count,self.dateSource.countand so on, Instead, the delegate will be better.

score 0 · Answer 11 · edited Nov 26 '17 at 22:02

0

This is the best way.

- (void)scrollToBottom
{
    CGFloat yOffset = 0;

    if (self.tableView.contentSize.height > self.tableView.bounds.size.height) {
        yOffset = self.tableView.contentSize.height - self.tableView.bounds.size.height;
    }

    [self.tableView setContentOffset:CGPointMake(0, yOffset) animated:NO];
}

edited Nov 26 '17 at 22:02

Dhiru

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answered Mar 06 '17 at 13:52

Jigar Patel

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score -1 · Answer 12 · answered May 10 '18 at 08:41

try this code, It may help you:

    self.tableView.reloadData()
    DispatchQueue.main.asyncAfter(deadline: DispatchTime.now()+0.1, execute: {
        let indexPath = IndexPath(row: self.dateSource.count-1, section: 0)
        self.tableView.scrollToRow(at: indexPath, at: UITableViewScrollPosition.bottom, animated: true)
    })

UITableView , Scroll to bottom on reload?

12 Answers12

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