How to set ContentSize of a UIScrollView which is a sub-view?

Question

I have an iPad app using Storyboards. I have one scene with a UIView, which has an additional UIView on the top half (which I draw on), and a UIScrollView on the bottom half (I needed to keeep them separate). I'm having a hard time figuring out how to address the UIView with this code that I copied from another SO question:

CGFloat scrollViewHeight = 0.0f;
for (UIView* view in scrollView.subviews)
{
   scrollViewHeight += view.frame.size.height;
}

[scrollView setContentSize:(CGSizeMake(320, scrollViewHeight))];

The way I read the code above, I'm supposed to use the UIView, but that doesn't make sense, since the UIView covers the entire "scene/window". It makes more sense to me to use the UIScrollView to calculate the ContentSize.

So, what am I supposed to use?

Can you explain a little more what the problem is and what you are trying to do? And what is that code supposed to do from where you took it? — pedros
The code I copied is supposed to find the height of the containing frame and set the ContentSize of the UIScrollView. The problem is I don't know if I'm supposed to use the UIView or the UIScrollView. The code isn't commented, and it makes absolutely no sense to me to get the frame height for the UIView, when the UIScrollView is the one that needs that information. HTH — SpokaneDude

Metabble Metabble · Accepted Answer · 2012-11-08T21:28:35

Not completely clear on what you are asking. Once you have a reference to the scroll view, either through tags, properties or some other method, you should set its content size to the width and height of all of its content combined (accounting for overlap, etc). Ex. if you had a single image view that was 600 by 900 points inside the scroll view, you'd set its size to a 600 by 900 CGSize.

That goes through all of the subviews of the scroll view using a for...in loop (aka fast enumeration), adding their heights together, then uses that as the height of the content. I don't think that would be a good way to do it, because that assumes that all the subviews are stacked vertically on top of one another perfectly. It's basically going, "For every subview of my scroll view, add their height to this total and then use that as the content size's height."

The easiest way to manage scroll views is to slap all the content into one UIView, place that in the scroll view, then set the scroll view's content size to the frame of the UIView. If you need a reference to the UIView contained in the scroll view, you can set it to a property or give it a tag and use viewWithTag.

How to set ContentSize of a UIScrollView which is a sub-view?

1 Answers