CODEWITHSUNDEEP
iosswiftswift3nslayoutconstraint
Varun Naharia
Varun Naharia

Reputation: 5420

How to remove a view and update constraints?

I have a view in which i am creating another view programmatically on add button through xib. I am able to create multiple views on tapping add more button and remove is also working if I remove last view but the problem occurs with middle views due to missing constraints view not updating correctly bellow are images how it is looking

At start view Look like this

enter image description here

After Adding more view

enter image description here

After removing middle view

enter image description here

Delete button code

@IBAction func deletebnt(_ sender: UIButton) {
        let view = self.superview
        let index =  view?.subviews.index(of:self)!
        delegate.txtcheck(text: countstr)
         self.view.removeFromSuperview()
    }

Add button Code

@IBAction func addMoreBnt(_ sender: UIButton) {
      for constraint in addSuperview.constraints {
            if constraint.firstAttribute == NSLayoutAttribute.height
            {
                constraint.constant +=  45
                space = constraint.constant
            }
        }
        let newView : AvalabileTimeView = AvalabileTimeView()
        newView.frame = CGRect(x: self.addsubView.frame.origin.x, y: 70, width: addsubView.frame.size.width, height:addsubView.frame.size.height)
        newView.delegate = self as AvalabileTimeDelegate
        addSuperview.addSubview(newView)
        let index = addSuperview.subviews.index(of: newView)!        
        newView.translatesAutoresizingMaskIntoConstraints = false
        let heightConstraint = newView.widthAnchor.constraint(equalToConstant:addsubView.frame.size.width )
        let widthConstaint = newView.heightAnchor.constraint(equalToConstant:31 )
        let topConstraint = newView.topAnchor.constraint(equalTo: addSuperview.topAnchor, constant: space - 31)  NSLayoutConstraint.activate([heightConstraint,topConstraint,widthConstaint])

    }

delegate to change height of superview

func txtcheck(text: String!) {
        print(text)
        for constraint in addSuperview.constraints {
            if constraint.firstAttribute == NSLayoutAttribute.height
            {
                constraint.constant -=  45
                // Here I have to set constraint for bottom view and topview of deleted view but I don't know how to do
            }
        }
    }

Here is link to demo project https://github.com/logictrix/addFieldDemo

Upvotes: 0

Views: 1633

Answers (1)

DonMag
DonMag

Reputation: 77423

Instead of adding each new AvalabileTimeView with its own constraints, use a UIStackView - you can remove almost all of your existing code for adding / removing the new views.

Look at .addArrangedSubview() and .removeArrangedSubview()

Here is some sample code... you'll need to add a UIStackView in Interface Builder, connect it to the Outlet, and adjust the constraints, but that's about all:

// in ViewController.swift

@IBOutlet weak var availableTimeStackView: UIStackView!

@IBAction func addMoreBnt(_ sender: UIButton) {

    // instantiate a new AvalabileTimeView
    let newView : AvalabileTimeView = AvalabileTimeView()

    // set its delegate to self
    newView.delegate = self as AvalabileTimeDelegate

    // add it to the Stack View
    availableTimeStackView.addArrangedSubview(newView)

    // standard for auto-layout
    newView.translatesAutoresizingMaskIntoConstraints = false

    // only constraint needed is Height (width and vertical spacing handled by the Stack View)
    newView.heightAnchor.constraint(equalToConstant: 31).isActive = true

}

// new delegate func
func removeMe(_ view: AvalabileTimeView) {

    // remove the AvalabileTimeView from the Stack View
    availableTimeStackView.removeArrangedSubview(view)

}

// in AvalabileTimeView.swift

protocol AvalabileTimeDelegate{
    // don't need this anymore
    func txtcheck(text: String!)

    // new delegate func
    func removeMe(_ view: AvalabileTimeView)
}

@IBAction func deletebnt(_ sender: UIButton) {
    delegate.removeMe(self)
}

Upvotes: 3

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