iOS how to check if go to the bottom of webView - ios

Question

Is there any event I can notify the supper view?
I try the scrollViewDidScroll. But it don't be called.
-(void)scrollViewDidScroll: (UIScrollView*)scrollView
{
NSLog(#"At the bottom...");
}

Answer 1

You must set the delegate of scrollview which in the webview to self first. So that, scrollViewDidScroll: could be call when you scroll the webview. So, try this:
- (void)viewDidLoad
{
[super viewDidLoad];
self.webview.scrollview.delegate = self;
}
- (void)scrollViewDidScroll:(UIScrollView*)scrollview
{
CGPoint offset = scrollView.contentOffset;
CGRect bounds = scrollView.bounds;
UIEdgeInsets inset = scrollView.contentInset;
CGFloat currentOffset = offset.y + bounds.size.height - inset.bottom;
if (currentOffset - scrollView.contentSize.height <= 0)
{
NSLog(#"At the bottom...");
}
}

Answer 2

If you have an instance of webView, you can get the reference of its scrollView by doing,
webView.scrollView. Set its delegate to self like so:
webView.scrollView.delegate = self;
Now, make sure you have implemented UIScrollViewDelegate in your class where you have an instance of the webView. Implement the below the code that tells you whether you have reached the bottom.
- (void)scrollViewDidEndDecelerating:(UIScrollView *)scrollView {
float bottomEdge = scrollView.contentOffset.y + scrollView.frame.size.height;
if (bottomEdge >= scrollView.contentSize.height) {
//This means that you have reached the end.
}
}

Answer 3

To get the call in scrollView delegate methods you need to assign the delegate for webview scroll view like this:
webview.scrollView.delegate = self;
Also Conform the UIScrollViewDelegate in .h file like this:
#interface MyController : UIViewController <UIScrollViewDelegate>
#end

Answer 4

If anyone is interested on how this is done in Swift 4, here it is:
Set the webviews' scrollView delegate to self in viewDidLoad() self.webView.scrollView.delegate = self
Extend your class from UIScrollViewDelegate
Implement the method scrollViewDidScroll() which will handle the scroll events
(this particular implementation is used to check if the user has scrolled to the bottom of the webview's content)
func scrollViewDidScroll(_ scrollView: UIScrollView) {
let bottom = scrollView.contentOffset.y + scrollView.frame.size.height
if (bottom >= scrollView.contentSize.height) {
// Do something here
}
}