resize superview after subviews change dynamically using autolayout

Question

I cant for the love of god the the hang of this resizing superview.

I have a UIView *superview with 4 UILabels. 2 function as header for t

Answer 1

This almost follows @smileyborg answer and comes with a concrete example.

Won't describe all constraints, but those related to the calculation of the height of UI objects.

1. [Label] Labels must not have a fixed height constraint, in this case, AutoLayout won't resize labels to fit the text, so setting edge constraints is the key. (green arrows)

2. [Subview] Steps 1 and 3 are very easy to follow, but this step can be misunderstood. As in the case with labels, subviews must not have height constraint set. All subviews must have top constraint set, ignoring bottom constraint, which can make you think will trigger unsatisfied constraint exception at runtime, but it won't if you set bottom constraint for the last subview. Missing to do so will blow the layout. (red arrows)

3. [Superview] Set all constraints the way you need, but pay big attention to the height constraint. Assign it a random value, but make it optional, AutoLayout will set the height exactly to fit the subviews. (blue arrows)

This works perfectly, there is no need to call any additional system-layout update methods.