CODEWITHSUNDEEP
swiftview
LetUsDevelop
LetUsDevelop

Reputation: 15

How to hide and unhide a view with height in swift?

I am trying to hide and unhide a view. Its size should be 0 when it is hidden and about 200 when it is unhidden. I have two view controllers. When the first controller shows the view is hidden for the first time and its size is set to 0 and then it navigates to other controller and takes some values from the textfeilds and display them on a tableview in previous controller.

Now, I am able to hide the view for the first time with height 0 but when I take up the values the view is still hidden.

This is the code I have tried so far:

mainView.isHidden == true
mainView.heightAnchor.constraint(equalToConstant: CGFloat(0)).isActive = true

// when I get the values but this code doesn't work
    mainView.isHidden == false
    mainView.heightAnchor.constraint(equalToConstant: CGFloat(100)).isActive = true

Any help would be appreciated.

Upvotes: 0

Views: 2319

Answers (3)

gcharita
gcharita

Reputation: 8347

You keep both created constraints in your view controller and activate however you need accordingly, using isActive property of NSLayoutConstraint:

var hiddenHeightConstraint: NSLayoutConstraint?
var showingHeightConstraint: NSLayoutConstraint?

var isMainViewHidden: Bool = false {
    didSet {
        mainView.isHidden == isMainViewHidden
        hiddenHeightConstraint?.isActive = isMainViewHidden
        showingHeightConstraint?.isActive = !isMainViewHidden
        
        // Don't forget to call layoutIfNeeded() when you messing with the constraints
        view.layoutIfNeeded()
    }
}

override func viewDidLoad() {
    super.viewDidLoad()
    
    hiddenHeightConstraint = mainView.heightAnchor.constraint(equalToConstant: CGFloat(0))
    showingHeightConstraint = mainView.heightAnchor.constraint(equalToConstant: CGFloat(100))
    
    isMainViewHidden = false
}

Upvotes: 0

parsa parand
parsa parand

Reputation: 52

class viewController: UIViewController {

     var height: NSLayoutConstraint!

     override func viewDidLoad() {
         super.viewDidLoad()
         
         height = mainView.heightAnch.constraint(equalToConstant: 0)
         height.isActive = true

         //handle change height
         if mainView.isHidden == true {
             height.constant = 0
         }
         else {
             height.constant = 200
         }
     }
}

Upvotes: 2

hessam
hessam

Reputation: 432

You have two options. The first method set identifier to height constraint

set identifier:

set identifier:

then find and change with below code:

// first option
        // find own constraint with indentifier
        if let heightConstraint = self.myView.constraints.first(where: { item -> Bool in
            return item.identifier == "heightIdentifier"
        }) {
            
            // set any constant to constraint
            heightConstraint.constant = 200.0 // for hidden
            heightConstraint.constant = 0.0 // for hide
            
            // any work
            
        }

second option: set IBOutlet to target constraint:

@IBOutlet weak var heightConstraint: NSLayoutConstraint!

then change direct and simple:

// second option
// change constant direct
self.heightConstraint.constant = 200.0 // for hidden
self.heightConstraint.constant = 0.0 // for hide
            
// any work

Upvotes: 0

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