无法以编程方式用视图填充超级视图

Question

I'll try to make subview's sizes same its superview.

override func viewDidLayoutSubviews() {
    subView.setTranslatesAutoresizingMaskIntoConstraints(true)
    let viewsDictionary = ["subView": subView]

    view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|[subView]|", options: nil, metrics: nil, views: viewsDictionary))
    view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|[subView]|", options: nil, metrics: nil, views: viewsDictionary))
}

What I do wrong?

=========================

Update!

subView.setTranslatesAutoresizingMaskIntoConstraints(false)
        let viewsDictionary = ["subView": subView]

        view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("V:|-0.0-[subView]-0.0-|", options: nil, metrics: nil, views: viewsDictionary))
        view.addConstraints(NSLayoutConstraint.constraintsWithVisualFormat("H:|-0.0-[subView]-0.0-|", options: nil, metrics: nil, views: viewsDictionary))
    }

But no effect =(

Thx a lot!

Answer 1

Two mistakes (at least). First:

subView.setTranslatesAutoresizingMaskIntoConstraints(true)

That needs to be false , not true .

Second: You don't want to simply do this in viewDidLayoutSubviews , because that method will be called many times during the life of your app, and you're going to be adding new constraints unconditionally every time.