Views do not respect 'Hidden' property in iOS 8 like they do in iOS9

[toddrick]

One of the perks of UIStackView is that hidden views do not affect the layout. So if a view is marked as hidden it's as if it didn't exist. This behavior is absent from iOS8, where marking a view as hidden will still force it to occupy it's space.

[sunnyxx]

Actually, a hidden subview DO affect the layout, UIStackView adds a width/height constraint of zero constant to make that hiding view "collapsed" , other constraints are still connecting against it, a zero width or height makes it not rendering.

[toddrick]

With FDStackView, it does not respect this. If you modify your demo project to sit views as hidden, the behavior differs depending on which iOS version you are running. I would consider this a bug.

[nobre84]

@sunnyxx If FDStackView can't animate hidden property as UIStackView can, this issue should remain open, don't you think?

[dsmo]

实际上 UIStackView 是不对 Hidden 的 Subview 做 layout 计算的，WWDC 201717#412 有提到，目前这个问题还是存在的，iOS 8 上不能通过设置 hidden 对 FDStackView 的 subviews 动态显示和隐藏