UIScrollView height while adding content programmatically in UIStackView

Question

I am trying to make a view containing an UIScrollView. This UIScrollView contains 3 UIViews. The last one contains another UIStackView I wanted to fill at runtime.

Here an image of the storyboard :

But when I add content at runtime in the second UIStackView, the ScrollView's height remains the same.

The second UIStackView is defined as the first one with:

Axis : vertical
Alignment : Fill
Distribution : Equal Spacing

Then I use :

mStackView.addArrangedSubview(matProgress)

The result below :

What's the way to have the bottom view and the ScrollView stretch to fit the content.

Do you initially show this with *empty* bottom view? Or when it is first shown it has *some* of the multiple-lines? — DonMag, May 12 '17 at 16:27
When it first shown it already has some views. The problem I had is described in my comment in the accepted answer — Mory, May 15 '17 at 08:24

score 2 · Accepted Answer · answered May 12 '17 at 18:58

The layout can be done with auto-layout and constraints.

The key points are:

do not set height constraints on either StackView
set the "Main" StackView Distribution to Equal Spacing
set the "Main" StackView Leading, Trailing, Top and Bottom constraints to its Superview (which is the ScrollView)
you do need to also set a width constraint on the "Main" StackView to control the horizontal contentSize

The only quirk will be on startup. If you have NO content in the bottom / inner StackView, it will still "exist" in the Main StackView and take up space. There is a trick to get around that, but it must be done in code.

You can see a working example here: https://github.com/DonMag/StackyScrolly

Thanks DonMag, the example you provide helped me to make it work. My project was working exactly as yours when I use `UILabels` as you've done. So the problem was that the views I added in the bottom `UIStackView` haven't got any height constraint... — Mory, May 15 '17 at 07:43

score 0 · Answer 2 · answered May 12 '17 at 16:58

If you have UIScrollView and the child views with auto-layout. Setting programmatically the height of the scrollview will stretch the inside views to comply with the auto-layout.

So, you get by code the height of the third view and set the UIScrollView height to view1.height + view2.height + expectedThirdViewHeight.

UIScrollView height while adding content programmatically in UIStackView

2 Answers2