CODEWITHSUNDEEP
iosswiftnslayoutconstraint
shaibow
shaibow

Reputation: 105

clear constraints when using NSLayoutAnchor

I'm new in creating views without interface builder . I'm using NSLayoutAnchors to create views!

when I'm using some view that created in viewcontroller like this : 

let borderView:UIView = {

    let view = UIView()
    view.translatesAutoresizingMaskIntoConstraints = false
    view.backgroundColor = UIColor.lightGray
    view.isUserInteractionEnabled = false
    view.alpha = 0.5
    return view

}()

then i use this view to border sth in view like this : 

view.addSubview(borderView)
borderView.bottomAnchor.constraint(equalTo: headerView.bottomAnchor).isActive = true
borderView.leftAnchor.constraint(equalTo: headerView.leftAnchor).isActive = true
borderView.rightAnchor.constraint(equalTo: headerView.rightAnchor).isActive = true
borderView.heightAnchor.constraint(equalToConstant: 1).isActive = true

then in another view i try this :

    informationView.addSubview(borderView)

    borderView.topAnchor.constraint(equalTo: informationView.topAnchor).isActive = true
    borderView.leftAnchor.constraint(equalTo: informationView.leftAnchor).isActive = true
    borderView.rightAnchor.constraint(equalTo: informationView.rightAnchor).isActive = true
    borderView.heightAnchor.constraint(equalToConstant: 1).isActive = true

but looks like this view has it's previous constraints end show constraints error !

how can I remove borderView constraints before reusing it ?

Upvotes: 2

Views: 5099

Answers (1)

Lou Franco
Lou Franco

Reputation: 89142

You can't reuse views. Each view can only be in the view hierarchy one time. You need to make a new bordered view object for each view you want to use it with.

To answer the question, you can remove constraints from a view with view.removeConstraints(view.constraints)

Upvotes: 7

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