Can't set translatesAutoresizingMaskIntoConstraints

Question

In an attempt to solve an Auto-Layout issue related to programmatically adding sub views to a scroll view, I have run into many references throughout the internet that, in various scenarios say to set translatesAutoresizingMaskIntoConstraints = YES or translatesAutoresizingMaskIntoConstraints = NO, depending on the case.

However, in Swift, when I type:

var view = UIView()
view.translatesAutoresizingMaskIntoConstraints = false

I get the in-line error: Cannot assign to 'translatesAutoresizingMaskIntoConstraints' in 'view'. Why? Because, when inspected, you'll find that it's a parameterless function, not a property.

I've gotten around this by subclassing, but it's a major inconvenience to have to subclass every view I'm dealing with, just to set translatesAutoresizingMaskIntoConstraints:

class CardView: UIView {
    override func translatesAutoresizingMaskIntoConstraints() -> Bool {
        return false
    }
}

Does anyone know a way around this, or can shed light on the discrepancy between what the general internet councils tell you and what you can actually do, in Swift?

Answer 1

translatesAutoresizingMaskIntoConstraints is actually a method on UIView and not a property.

The syntax works because ObjC lets you use dot-notation for calling methods as well (there's a whole other discussion on how properties actually auto-generate getter/setter methods).

Use the method instead of trying to use the property notation from ObjC

view.setTranslatesAutoresizingMaskIntoConstraints(false)