scrollViewDidScroll: when scroll programmatically?

Question

I have this delegate which intended to be execute when user scrolls with his fingers :

-(void)scrollViewDidScroll:(UIScrollView *)scrollView

I have this line that scroll with code to the start :

[scroller scrollRectToVisible:CGRectMake(0, 0,scroller.frame.size.width,scroller.frame.size.height) animated:YES];

When i execute this line of code to scroll programmatically, the first delegate is also being called. I would like to eliminate this from happen.

I was trying to set the delegate to nil, but it still execute the delegate:

scroller.delegate=nil;//to not excute scrolldidscroll
[scroller scrollRectToVisible:CGRectMake(0, 0,scroller.frame.size.width,scroller.frame.size.height) animated:YES];
scroller.delegate=self;

EDIT:

I have read this great answer :Setting contentOffset programmatically triggers scrollViewDidScroll but it seems that his solution(the first) is without animation, while i need that animation .

streem · Accepted Answer · 2014-05-23 13:21:09Z

7

There might be a better solution but this should work :

Declare a boolean in your .h

@property(nonatomic,assign) BOOL scrollingProgrammatically;

And in your .m :

self.scrollingProgrammatically = YES;
[scroller scrollRectToVisible:CGRectMake(0, 0,scroller.frame.size.width,scroller.frame.size.height) animated:YES];

...

-(void)scrollViewDidScroll:(UIScrollView *)scrollView{
    if(!self.scrollingProgrammatically){
        ...
    }
}

-(void)scrollViewDidEndScrollingAnimation:(UIScrollView *)scrollView{
    self.scrollingProgrammatically = NO;
}

edited May 23, 2014 at 13:21

answered May 23, 2014 at 13:09

streem

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3 Comments

Curnelious Over a year ago

Ok , i will go for it .. :)

streem Over a year ago

hmm, yeah there is probably no lighter way to do this. Also I've edited my answer since didEndDragging is not called if scroll is called programmatically.

Curnelious Over a year ago

it actually did ! the dragging method(your first answer) did worked for me as well. strange .

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