UIScrollView, reaching the bottom of the scroll view

Question

I know the Apple documentation has the following delegate method:

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView;      // called when scroll         


        

Answer 1

It work in Swift 3:

override func scrollViewDidScroll(_ scrollView: UIScrollView) {
    if scrollView.contentOffset.y == (scrollView.contentSize.height - scrollView.frame.size.height) {
        loadMore()
    }
}

Answer 2

I Think @bensnider answer is correct, But not exart. Because of these two reasons

1. - (void)scrollViewDidScroll:(UIScrollView *)scrollView{}

This method will call continuously if we check for if (bottomEdge >= scrollView.contentSize.height)

2 . In this if we go for == check also this condition will valid for two times.

• (i) when we will scroll up when the end of the scroll view touches the bottom edge
• (ii) When the scrollview bounces back to retain it's own position

I feel this is more accurate.

Very few cases this codition is valid for two times also. But User will not come across this.

- (void)scrollViewDidScroll:(UIScrollView *)scrollView
 {
    if (scrollView.contentOffset.y == roundf(scrollView.contentSize.height-scrollView.frame.size.height)) {
    NSLog(@"we are at the enffffdd");

   //Call your function here...

    }
}

Answer 3

The accepted answer works only if the bottom contentInset value is non-negative. A slight evolution would consider the bottom of the contentInset regardless of it's sign:

CGFloat bottomInset = scrollView.contentInset.bottom;
CGFloat bottomEdge = scrollView.contentOffset.y + scrollView.frame.size.height - bottomInset;
if (bottomEdge == scrollView.contentSize.height) {
    // Scroll view is scrolled to bottom
}

Answer 4

See what items are currently displayed in the UIView, using something like indexPathsForVisibleRows and if your model has more items than displayed, put an arrow at the bottom.

Answer 5

So if you want it in swift, here you go:

override func scrollViewDidScroll(_ scrollView: UIScrollView) {

    if (scrollView.contentOffset.y >= (scrollView.contentSize.height - scrollView.frame.size.height)) {
        //reach bottom
    }

    if (scrollView.contentOffset.y < 0){
        //reach top
    }

    if (scrollView.contentOffset.y >= 0 && scrollView.contentOffset.y < (scrollView.contentSize.height - scrollView.frame.size.height)){
        //not top and not bottom
    }
}

Answer 6

I think what you might be able to do is to check that your contentOffset point is at the bottom of contentSize. So you could probably do something like:

- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
    float bottomEdge = scrollView.contentOffset.y + scrollView.frame.size.height;
    if (bottomEdge >= scrollView.contentSize.height) {
        // we are at the end
    }
}

You'll likely also need a negative case there to show your indicator when the user scrolls back up. You might also want to add some padding to that so, for example, you could hide the indicator when the user is near the bottom, but not exactly at the bottom.