Hi,
I finally managed to get back on this! I've got it working when scrolling from
left to right and can detect when the user scrolls past the last item, however,
I can't seem to find a way to detect when the user scrolls to before the first
item.
I get -0 for offset X
2013-10-08 20:18:20.607 LTWScrollTest1[17988:a0b] contentOffset : {-0, 0}
But that doesn't do me much good!
It seems to work quite nicely going left to right, but having difficulties
figuring out how to make it work scrolling right to left.
Any idea greatly appreciated as I'm need to get this working for tomorrow
morning!
Thanks a lot.
All the Best
Dave
On 8 Oct 2013, at 08:56, Kyle Sluder <k...@ksluder.com> wrote:
>> On Oct 8, 2013, at 12:44 AM, Dave <d...@looktowindward.com> wrote:
>>
>> Thanks Kyle,
>>
>> That's what I was trying to figure out, whether I needed to re-layout the
>> views based on the positions or whether I could just do it by keeping an
>> Array of the image views separately and rotating this as it scroll past the
>> end. I sort of got this working, but of course the Subviews of the Scroll
>> View just grows and grows!
>>
>> This is what I got at the moment:
>>
>> // Scroll past last item detected (in the scrollViewDidScroll delegate
>> method)
>>
>> if (theScrollView.contentSize.width - theScrollView.contentOffset.x <=
>> 1024)
>> {
>> myContentInfo = [self.pContentArray objectAtIndex:0];
>> [self.pContentArray addObject:myContentInfo];
>> [self.pContentArray removeObjectAtIndex:0];
>>
>> [self addContentInfo:myContentInfo withEndFlag:YES];
>> }
>>
>> Which kind of works, but obviously isn't the way to do it.
>>
>> Thanks for confirming I needed to use -layoutSubviews, I'm about to start on
>> this track now.
>
> You don’t *have* to use -layoutSubviews, but you'll probably get the best
> results if you do. You could theoretically do this all in the delegate's
> implementation of -scrollViewDidScroll:, but that’ll probably double the
> number of layout passes and certainly multiply the number of message sends.
> When scrolling, you want to avoid as much unnecessary work as is reasonable.
>
> It’s kind of a bummer that you’re going to need to split your logic up
> between the scroll view and its delegate, thus tightly coupling the two. I
> wish the frameworks exposed many more of their delegate hooks as subclass
> hooks as well. Scroll views seem to stir this desire particularly frequently.
>
> --Kyle Sluder
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