Re: Infinite Scroll View?
Re: Infinite Scroll View?
- Subject: Re: Infinite Scroll View?
- From: Dave <email@hidden>
- Date: Tue, 08 Oct 2013 21:29:07 +0100
Well, it never goes less than -0 whatever that means so the "<" is redundant and 0 is a valid offset, I need to detect a scroll to *before* 0, which I never get.
Thanks
Dave
On 8 Oct 2013, at 21:26, Steve Christensen <email@hidden> wrote:
> Does (scrollView.contentOffset.x <= 0) not work? How are you testing for it now?
>
>
> On Oct 8, 2013, at 12:20 PM, Dave <email@hidden> wrote:
>
>> 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 <email@hidden> wrote:
>>
>>>> On Oct 8, 2013, at 12:44 AM, Dave <email@hidden> 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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