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How to know when UITableView did scroll to bottom in iPhone

I would like to know when a UITableView did scroll to bottom in order to load and show more content, something like a delegate or something else to let the controller know when the table did scroll to bottom.

How can I do this?

like image 565
Son Nguyen Avatar asked Feb 28 '11 03:02

Son Nguyen


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16 Answers

in the tableview delegate do something like this

ObjC:

- (void)scrollViewDidScroll:(UIScrollView *)aScrollView {
    CGPoint offset = aScrollView.contentOffset;
    CGRect bounds = aScrollView.bounds;
    CGSize size = aScrollView.contentSize;
    UIEdgeInsets inset = aScrollView.contentInset;
    float y = offset.y + bounds.size.height - inset.bottom;
    float h = size.height;
    // NSLog(@"offset: %f", offset.y);   
    // NSLog(@"content.height: %f", size.height);   
    // NSLog(@"bounds.height: %f", bounds.size.height);   
    // NSLog(@"inset.top: %f", inset.top);   
    // NSLog(@"inset.bottom: %f", inset.bottom);   
    // NSLog(@"pos: %f of %f", y, h);

    float reload_distance = 10;
    if(y > h + reload_distance) {
        NSLog(@"load more rows");
    }
}

Swift:

func scrollViewDidScroll(_ scrollView: UIScrollView) {
    let offset = scrollView.contentOffset
    let bounds = scrollView.bounds
    let size = scrollView.contentSize
    let inset = scrollView.contentInset
    let y = offset.y + bounds.size.height - inset.bottom
    let h = size.height
    let reload_distance:CGFloat = 10.0
    if y > (h + reload_distance) {
        print("load more rows")
    }
}
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neoneye Avatar answered Oct 05 '22 04:10

neoneye


Modified neoneyes answer a bit.

This answer targets those of you who only wants the event to be triggered once per release of the finger.

Suitable when loading more content from some content provider (web service, core data etc). Note that this approach does not respect the response time from your web service.

- (void)scrollViewDidEndDragging:(UIScrollView *)aScrollView
                  willDecelerate:(BOOL)decelerate
{
    CGPoint offset = aScrollView.contentOffset;
    CGRect bounds = aScrollView.bounds;
    CGSize size = aScrollView.contentSize;
    UIEdgeInsets inset = aScrollView.contentInset;
    float y = offset.y + bounds.size.height - inset.bottom;
    float h = size.height;

    float reload_distance = 50;
    if(y > h + reload_distance) {
        NSLog(@"load more rows");
    }
}
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Eyeball Avatar answered Oct 05 '22 03:10

Eyeball


add this method in the UITableViewDelegate:

-(void)scrollViewDidScroll:(UIScrollView *)scrollView
{   
    CGFloat height = scrollView.frame.size.height;

    CGFloat contentYoffset = scrollView.contentOffset.y;

    CGFloat distanceFromBottom = scrollView.contentSize.height - contentYoffset;

    if(distanceFromBottom < height) 
    {
        NSLog(@"end of the table");
    }
}
like image 37
8suhas Avatar answered Oct 05 '22 04:10

8suhas


None of the answers above helped me, so I came up with this:

- (void)scrollViewDidEndDecelerating:(UIScrollView *)aScrollView
{   
    NSArray *visibleRows = [self.tableView visibleCells];
    UITableViewCell *lastVisibleCell = [visibleRows lastObject];
    NSIndexPath *path = [self.tableView indexPathForCell:lastVisibleCell];
    if(path.section == lastSection && path.row == lastRow)
    {
        // Do something here
    }
}
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Iftach Orr Avatar answered Oct 05 '22 03:10

Iftach Orr


in Swift you can do something like this. Following condition will be true every time you reach end of the tableview

func tableView(tableView: UITableView, willDisplayCell cell: UITableViewCell, forRowAtIndexPath indexPath: NSIndexPath) {
        if indexPath.row+1 == postArray.count {
            println("came to last row")
        }
}
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Jay Mayu Avatar answered Oct 05 '22 02:10

Jay Mayu


The best way is to test a point at the bottom of the screen and use this method call when ever the user scrolls (scrollViewDidScroll):

- (NSIndexPath *)indexPathForRowAtPoint:(CGPoint)point

Test a point near the bottom of the screen, and then using the indexPath it returns check if that indexPath is the last row then if it is, add rows.

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Ajay Avatar answered Oct 05 '22 04:10

Ajay


Use – tableView:willDisplayCell:forRowAtIndexPath: (UITableViewDelegate method)

Simply compare the indexPath with the items in your data array (or whatever data source you use for your table view) to figure out if the last element is being displayed.

Docs: http://developer.apple.com/library/ios/documentation/uikit/reference/UITableViewDelegate_Protocol/Reference/Reference.html#//apple_ref/occ/intfm/UITableViewDelegate/tableView:willDisplayCell:forRowAtIndexPath:

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Wolfgang Schreurs Avatar answered Oct 05 '22 04:10

Wolfgang Schreurs


UITableView is a subclass of UIScrollView, and UITableViewDelegate conforms to UIScrollViewDelegate. So the delegate you attach to the table view will get events such as scrollViewDidScroll:, and you can call methods such as contentOffset on the table view to find the scroll position.

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Anomie Avatar answered Oct 05 '22 02:10

Anomie


NSLog(@"%f / %f",tableView.contentOffset.y, tableView.contentSize.height - tableView.frame.size.height);

if (tableView.contentOffset.y == tableView.contentSize.height - tableView.frame.size.height)
        [self doSomething];

Nice and simple

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user1641587 Avatar answered Oct 05 '22 04:10

user1641587


Building on @Jay Mayu's answer, which I felt was one of the better solutions:

Objective-C

// UITableViewDelegate
- (void)tableView:(UITableView *)tableView willDisplayCell:(UITableViewCell *)cell forRowAtIndexPath:(NSIndexPath *)indexPath {

// Need to call the service & update the array
if(indexPath.row + 1 == self.sourceArray.count) {
    DLog(@"Displayed the last row!");
  }
}

Swift 2.x

// UITableViewDelegate
func tableView(tableView: UITableView, willDisplayCell cell: UITableViewCell, forRowAtIndexPath indexPath: NSIndexPath) {
    if (indexPath.row + 1) == sourceArray.count {
        print("Displayed the last row!")
    }
}
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footyapps27 Avatar answered Oct 05 '22 02:10

footyapps27


Here is the swift 3.0 version code.

   func scrollViewDidScroll(_ scrollView: UIScrollView) {

        let offset = scrollView.contentOffset
        let bounds = scrollView.bounds
        let size = scrollView.contentSize
        let inset = scrollView.contentInset
        let y: Float = Float(offset.y) + Float(bounds.size.height) + Float(inset.bottom)
        let height: Float = Float(size.height)
        let distance: Float = 10

        if y > height + distance {
            // load more data
        }
    }
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Morshed Alam Avatar answered Oct 05 '22 03:10

Morshed Alam


I generally use this to load more data , when last cell starts display

-(UITableViewCell *)tableView:(UITableView *)tableView cellForRowAtIndexPath:(NSIndexPath *)indexPath
{
   if (indexPath.row ==  myDataArray.count-1) {
        NSLog(@"load more");
    }
}
like image 43
Shaik Riyaz Avatar answered Oct 05 '22 02:10

Shaik Riyaz


Taking neoneye excellent answers but in swift, and renaming of the variables..

Basically we know we have reached the bottom of the table view if the yOffsetAtBottom is beyond the table content height.

func isTableViewScrolledToBottom() -> Bool {
    let tableHeight = tableView.bounds.size.height
    let contentHeight = tableView.contentSize.height
    let insetHeight = tableView.contentInset.bottom

    let yOffset = tableView.contentOffset.y
    let yOffsetAtBottom = yOffset + tableHeight - insetHeight

    return yOffsetAtBottom > contentHeight
}
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samwize Avatar answered Oct 05 '22 04:10

samwize


My solution is to add cells before tableview will decelerate on estimated offset. It's predictable on by velocity.

- (void)scrollViewWillEndDragging:(UIScrollView *)scrollView withVelocity:(CGPoint)velocity targetContentOffset:(inout CGPoint *)offset {

    NSLog(@"offset: %f", offset->y+scrollView.frame.size.height);
    NSLog(@"Scroll view content size: %f", scrollView.contentSize.height);

    if (offset->y+scrollView.frame.size.height > scrollView.contentSize.height - 300) {
        NSLog(@"Load new rows when reaches 300px before end of content");
        [[DataManager shared] fetchRecordsNextPage];
    }
}
like image 29
fir Avatar answered Oct 05 '22 04:10

fir


Update for Swift 3

Neoneye's answer worked best for me in Objective C, this is the equivalent of the answer in Swift 3:

func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) {
    let offset: CGPoint = scrollView.contentOffset
    let bounds: CGRect = scrollView.bounds
    let size: CGSize = scrollView.contentSize
    let inset: UIEdgeInsets = scrollView.contentInset
    let y: CGFloat = offset.y + bounds.size.height - inset.bottom
    let h: CGFloat = size.height
//        print("offset: %f", offset.y)
//        print("content.height: %f", size.height)
//        print("bounds.height: %f", bounds.size.height)
//        print("inset.top: %f", inset.top)
//        print("inset.bottom: %f", inset.bottom)
//        print("position: %f of %f", y, h)

    let reloadDistance: CGFloat = 10

    if (y > h + reloadDistance) {
            print("load more rows")
    }
}
like image 37
Ibrahim Avatar answered Oct 05 '22 02:10

Ibrahim


I want perform some action on my any 1 full Tableviewcell.

So the code is link the :

-(void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView
{
    NSArray* cells = self.tableView.visibleCells;
    NSIndexPath *indexPath = nil ;

    for (int aIntCount = 0; aIntCount < [cells count]; aIntCount++)
    {

        UITableViewCell *cell = [cells objectAtIndex:aIntCount];
CGRect cellRect = [self.tableView convertRect:cell.frame toView:self.tableView.superview];

        if (CGRectContainsRect(self.tableView.frame, cellRect))
        {
            indexPath = [self.tableView indexPathForCell:cell];

    //  remain logic
        }
     }
}

May this is help to some one.

like image 22
Mayuri R Talaviya Avatar answered Oct 05 '22 03:10

Mayuri R Talaviya