Xamarin iOS: Auto Layout within scroll view?

问题:

I have a scrollView on my storyboard on which I have added top, left, right, bottom constraints in order for it to resize automatically in accordance with different screen sizes. The problem is that if I add image view or any other stuff within this scroll view and place constraints on this image view to maintain some distance from top, left, right and bottom of the scrollview boundaries. It just doesn't work. I Would like to have everything resized according to the screen size of the target device. How could I do so?

Light Grey area is my scrollview, grey area is plain view, innermost element is imageview.

回答1:

It is a little complicated to explain.

As we know , before the autolayout get working, we should set constraints on them , according to those constraints the compiler can determine the Frame (position and size) on controls.

However, UIScrollView is a bit of different from UIView. In general, we just need to set left,right,top,bottom , but in UIScrollView, it has a definition called contentSize which determines the actual size of scrollview. so the constraints we set above is not enough.

So, as a workaround ,we add a container view inside the scrollview to determine contentSize.

1. Constraint on scrollview (green area in the following gif)

2. Constraint on container view.(red area in the following gif)

pay attention: we set additional width (equal to scrollview) in order to indicate the the width is fixed , means we can't scroll horizontally but vertical orientation is allowed.

3. Constraint on inner view(blue area in the following gif)

Test result :

iPhone5S

iPad Air2

回答2:

I' ve encountered this question while I was struggling with this problem. The accepted answer is quite right, even if it leaves out some details.

Here I've made a complete answer will all the details,

https://stackoverflow.com/a/49096334/3765617

I write it here because maybe it will be helpful for someone in the future.