UIScrollView with custom paging?

samurle · 10-19-2011, 04:17 PM

I'm trying to create a UIScrollView with custom paging, however, I'm having an issue with
how the paging decelerates.

Whenever the UIScrollView deceleration routine kicks in, the paging doesn't "decelerate to" my custom paging offset.
Instead, it stops anywhere it wants. Then, I have to tell it where I want the offset to go.
I find this stop-and-go behavior annoying.

Can anyone tell me if this new delegate solves this problem?

Code:

scrollViewWillEndDragging:withVelocity:targetContentOffset:

I'm assuming if I set targetContentOffset to my custom paging offset, then it should fix my
stop-and-go problem.

But, it's only available with iOS 5.0. I'm not a paid developer, so I guess I can't use it?

Domele · 10-19-2011, 05:18 PM

The only reason you need to be paid developer is to test on devices and release your app to the app store. Everything else, you can either buy for a minimal amount (ex. Xcode 4 $5) or get for free.

Everyone (developers) has equal access to the SDK.

samurle · 10-19-2011, 05:27 PM

Quote:

Originally Posted by Domele

The only reason you need to be paid developer is to test on devices and release your app to the app store. Everything else, you can either buy for a minimal amount (ex. Xcode 4 $5) or get for free.

Everyone (developers) has equal access to the SDK.

That doesn't appear to be so:

iOS 5 for Developers - Apple Developer

Quote:

Download iOS 5 SDK
iOS 5 and iOS 5 SDK are available to iOS Developer Program members.

Quote:

You do not have access to this resource based on your membership.
Access to technical resources such as pre-release software and associated documentation, and information related to distributing iOS or Mac apps on the App Store are benefits offered to Apple Developer Program members.

I can't download it without being a paid developer. I can only download XCode 4.1.

I just want to know if this new UIScrollView delegate will solve my problem??

Domele · 10-19-2011, 05:43 PM

I have no idea if it'll solve your problem or not but you CAN download the SDK without paying. Go here, log in (or create an account if you don't have one), and go to downloads. The only difference is that paid developer accounts have access to Xcode for Snow Leopard.

samurle · 10-19-2011, 06:14 PM

Quote:

Originally Posted by Domele

I have no idea if it'll solve your problem or not but you CAN download the SDK without paying. Go here, log in (or create an account if you don't have one), and go to downloads. The only difference is that paid developer accounts have access to Xcode for Snow Leopard.

Ah, thanks, my fault. I didn't know iOS 5.0 was part of XCode 4.2.
I guess I was trying to download XCode5 or something.

Downloading it now.

samurle · 10-19-2011, 09:19 PM

Well, I finally got it installed, and...it doesn't work very good.

Adding this delegate kills the deceleration. The scrolling abruptly stops the
moment it hits a paging offset.

And about half the time, it stops halfway, and doesn't even make it.

I'm going back to iOS 4.3.

Domele · 10-19-2011, 10:09 PM

So why don't you just remove the delegate method?

samurle · 10-19-2011, 11:03 PM

Quote:

Originally Posted by Domele

So why don't you just remove the delegate method?

I finally got it working, with the new delegate method!

I was trying to set targetContentOffset with scrollView.contentOffset, which was wrong.

targetContentOffset already contains a valid offset, that was presumably calculated using
the passed velocity. I just needed to adjust targetContentOffset, and it magically decelerates
to the correct offset. No more abrupt stops. Awesome.