Swift how to set UIView's height constraint based on it's content - ios

Question

I have a UIView in my swift code
let profile_inf_wrapper: UIView = {
let v = UIView()
v.backgroundColor = .red
v.translatesAutoresizingMaskIntoConstraints = false
return v
}()
profile_inf_wrapper.topAnchor.constraint(equalTo: view.topAnchor, constant:64).isActive = true
profile_inf_wrapper.leftAnchor.constraint(equalTo: view.leftAnchor).isActive = true
profile_inf_wrapper.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
profile_inf_wrapper.heightAnchor.constraint(equalToConstant: view.frame.height/4).isActive = true
backgroundImageView.topAnchor.constraint(equalTo: profile_inf_wrapper.topAnchor).isActive = true
backgroundImageView.leftAnchor.constraint(equalTo: profile_inf_wrapper.leftAnchor).isActive = true
backgroundImageView.rightAnchor.constraint(equalTo: profile_inf_wrapper.rightAnchor).isActive = true
backgroundImageView.bottomAnchor.constraint(equalTo: profile_inf_wrapper.bottomAnchor).isActive = true
profileImage.centerYAnchor.constraint(equalTo: profile_inf_wrapper.centerYAnchor).isActive = true
profileImage.leftAnchor.constraint(equalTo: view.leftAnchor, constant:25).isActive = true
profileImage.widthAnchor.constraint(equalToConstant: 110).isActive = true
profileImage.heightAnchor.constraint(equalToConstant: 110).isActive = true
usernameLabel.topAnchor.constraint(equalTo: profile_inf_wrapper.topAnchor, constant:40).isActive = true
usernameLabel.leftAnchor.constraint(equalTo: profileImage.rightAnchor, constant:20).isActive = true
countryIcon.topAnchor.constraint(equalTo: usernameLabel.bottomAnchor, constant:10).isActive = true
countryIcon.leftAnchor.constraint(equalTo: profileImage.rightAnchor, constant:20).isActive = true
countryIcon.widthAnchor.constraint(equalToConstant: 25).isActive = true
countryIcon.heightAnchor.constraint(equalToConstant: 25 ).isActive = true
countryName.topAnchor.constraint(equalTo: usernameLabel.bottomAnchor, constant:5).isActive = true
countryName.leftAnchor.constraint(equalTo: countryIcon.rightAnchor, constant:10).isActive = true
countryName.rightAnchor.constraint(equalTo: view.rightAnchor).isActive = true
All these elements are the subviews of profile_inf_wrapper.Sometimes view.frame.height/4 is too small and i want to be able to resize the UIView based on it's content

Answer 1

There's a property in UIView called intrinsicContentSize. It returns the smallest size that the view would need show all of it's content.
While the default implementation is not very useful because a UIView doesn't have any content on it's own, all of the default subclasses implement it.
A UILabel will return a size that fits the text perfectly, and a UIButton will return a size that fits it's contents plus whatever spacing you've added. You get the gist of it.
You can take advantage of this property by only constraining either width or height of a view, not both. If you constrain the width of a UILabel and add more text, it will grow vertically.
Finally, when you add subviews to a UIView, and you add constraints to both margins of an axis (top and bottom or left and right), as long as there's a "chain" of constraints and views, and the view doesn't have any constraints on the size, it will expand to fit.
For example, if you have a view with a label and a button, vertically arranged, if the label is constrained to the top, then constrained to the button, and the button is constrained to the bottom, as long as the container view doesn't have a height constraint, it will expand to fit the two views plus the margins perfectly.
Your goal should always be to use the least amount of constraints to express your design, without removing useful constraints. Make sure you take advantage of the intrinsicContentSize.

Answer 2

For setting the height of uiview dynamically you have to add height/bottom constraint to the view in your problem it might be
profile_inf_wrapper.heightAnchor.constraint(equalToConstant: view.frame.height/4+countryName.frame.size.height).isActive = true
you also need the view size to fit to get actual updated size
like
countryName.sizeToFit()
And then update layout if needed to get all affect

Answer 3

The first thing you want to do is make a reference to the height constraint of profile_inf_wrapper.
var profile_inf_wrapper_height_constraint: NSLayoutConstraint?
I don't know the details of your content, but when the view needs resized, you can check that with a conditional in your viewController,
if contentRequiresResizing {
profile_inf_wrapper_height_constraint.constant = view.frame.width/3
else {
profile_inf_wrapper_height_constraint.constant = view.frame.width/4
}
By referencing constraints, it allows you to support dynamic UI changes easily.
As a side note, I would recommend renaming your UIView variable name so that the reference constraint isn't so long. The Swift 3 API guidelines also support lowerCamelCase, as opposed to underscore naming.