如何在按钮单击时在一个视图控制器中正确启用和禁用约束

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【中文标题】如何在按钮单击时在一个视图控制器中正确启用和禁用约束【英文标题】:How to properly enable and disable constraint in one view controller on button click 【发布时间】:2020-01-08 10:32:58 【问题描述】:

我在 Storyboard 上有一个 UIView 作为 ViewController 的子视图,并且该视图中有一些字段,必须在单击按钮时更改其位置。所以我改变了,所以我为每个 FiledsView 创建了一个出口,并以编程方式给它们提供了约束,但问题是当我点击其他按钮时它们相互重叠和冲突。

这是我要制作的布局

这里我把所有字段放在另一个视图中

这是代码

import UIKit

class AddOfferTabViewController: UIViewController 

    @IBOutlet weak var formBaseView: UIView!
    @IBOutlet weak var titleFieldView: RoundView!
    @IBOutlet weak var descriptionView: RoundView!
    @IBOutlet weak var pointsView: RoundView!
    @IBOutlet weak var startEndDateStackView: UIStackView!
    @IBOutlet weak var maxCharLimitStackView: UIStackView!
    @IBOutlet weak var amountView: RoundView!

    @IBOutlet weak var textViewDescription: TextViewWithPlaceholder!
    @IBOutlet weak var textFieldAmount: UITextField!


    var buttonClicked:String!

    override func viewDidLoad() 
        super.viewDidLoad()
        self.tabBarController?.tabBar.isHidden = true

       // setupCashDiscountView(isLayoutActive: true)
        setupFreebeView(isLayoutActive: true)

    


    @IBAction func addOfferButtonsActions(_ sender: UIButton) 

        switch sender.tag 
        case 1: //FreeBe
            print("Freebe")
            buttonClicked = "Freebe"
            setupCashDiscountView(isLayoutActive: false)
            setupPercentDiscountView(isLayoutActive: false)
            setupFreebeView(isLayoutActive: true)
        case 2: //Cash Discount
            print("Cash Discount")
            buttonClicked = "Cash"
            setupFreebeView(isLayoutActive: false)
            setupPercentDiscountView(isLayoutActive: false)
            setupCashDiscountView(isLayoutActive: true)

        case 3: //% Discount
            print("% Discount")
            buttonClicked = "percent"
            setupFreebeView(isLayoutActive: false)
            setupCashDiscountView(isLayoutActive: false)
            setupPercentDiscountView(isLayoutActive: true)
        default:
            print("there is something wrong")
        

    


    //MARK:Setup FreebeView
    func setupFreebeView(isLayoutActive:Bool)

        amountView.isHidden = true
        textViewDescription.placeholderText = "Any T&C"

        setupInputFields(fieldView: titleFieldView, topConstraints: formBaseView.topAnchor, leadingSpace: 0, trailingSpace: 0, topSpace: 8, height: 44, isActive: isLayoutActive) //Title Input Field
        setupInputFields(fieldView: descriptionView, topConstraints: titleFieldView.bottomAnchor, leadingSpace: 0, trailingSpace: 0, topSpace: 15, height: 95, isActive: isLayoutActive) //Description View
        setupMaxCharStackView(formStackView: maxCharLimitStackView, topConstraints: descriptionView.bottomAnchor, trailingSpace: 0, topSpace: 10, isActive: isLayoutActive) //Character Limit View

        setupInputFields(fieldView: pointsView, topConstraints: descriptionView.bottomAnchor, leadingSpace: 0, trailingSpace: 0, topSpace: 40, height: 44, isActive: isLayoutActive) //PointsView

        setupStartEndDateStackView(formStackView: startEndDateStackView, topConstraints: pointsView.bottomAnchor, leadingSpace: 0, trailingSpace: 0, topSpace: 15, isActive: isLayoutActive) //StartDate Endate



    

    //MARK:Setup CashDiscount
    func setupCashDiscountView(isLayoutActive:Bool)

        amountView.isHidden = false
        textViewDescription.placeholderText = "Description"

        setupInputFields(fieldView: amountView, topConstraints: formBaseView.topAnchor, leadingSpace: 0, trailingSpace: 0, topSpace: 8, height: 44, isActive: isLayoutActive) //Amount View

        setupInputFields(fieldView: pointsView, topConstraints: amountView.bottomAnchor, leadingSpace: 0, trailingSpace: 0, topSpace: 15, height: 44, isActive: isLayoutActive) //Points View

        setupStartEndDateStackView(formStackView: startEndDateStackView, topConstraints: pointsView.bottomAnchor, leadingSpace: 0, trailingSpace: 0, topSpace: 15, isActive: isLayoutActive) //StartDate Endate

         setupInputFields(fieldView: titleFieldView, topConstraints: startEndDateStackView.bottomAnchor, leadingSpace: 0, trailingSpace: 0, topSpace: 15, height: 44, isActive: isLayoutActive) //Title View

        setupInputFields(fieldView: descriptionView, topConstraints: titleFieldView.bottomAnchor, leadingSpace: 0, trailingSpace: 0, topSpace: 15, height: 95, isActive: isLayoutActive) //Description View

        setupMaxCharStackView(formStackView: maxCharLimitStackView, topConstraints: descriptionView.bottomAnchor, trailingSpace: 0, topSpace: 10, isActive: isLayoutActive) //Character Limit View


    


    //MARK:Setup % Discount
    func setupPercentDiscountView(isLayoutActive:Bool)

        amountView.isHidden = false
        textViewDescription.placeholderText = "Description"

        setupInputFields(fieldView: amountView, topConstraints: formBaseView.topAnchor, leadingSpace: 0, trailingSpace: 0, topSpace: 8, height: 44, isActive: isLayoutActive) //Amount View

        setupInputFields(fieldView: pointsView, topConstraints: amountView.bottomAnchor, leadingSpace: 0, trailingSpace: 0, topSpace: 15, height: 44, isActive: isLayoutActive) //Points View

        setupStartEndDateStackView(formStackView: startEndDateStackView, topConstraints: pointsView.bottomAnchor, leadingSpace: 0, trailingSpace: 0, topSpace: 15, isActive: isLayoutActive) //StartDate Endate

        setupInputFields(fieldView: titleFieldView, topConstraints: startEndDateStackView.bottomAnchor, leadingSpace: 0, trailingSpace: 0, topSpace: 15, height: 44, isActive: isLayoutActive) //Title View

        setupInputFields(fieldView: descriptionView, topConstraints: titleFieldView.bottomAnchor, leadingSpace: 0, trailingSpace: 0, topSpace: 15, height: 95, isActive: isLayoutActive) //Description View

        setupMaxCharStackView(formStackView: maxCharLimitStackView, topConstraints: descriptionView.bottomAnchor, trailingSpace: 0, topSpace: 10, isActive: isLayoutActive) //Character Limit View

    

    //MARK: SetupInputFields function
    func setupInputFields(fieldView:UIView,topConstraints:NSLayoutAnchor<NSLayoutYAxisAnchor>,leadingSpace:CGFloat,trailingSpace:CGFloat,topSpace:CGFloat,height:CGFloat,isActive:Bool)
        fieldView.translatesAutoresizingMaskIntoConstraints = false //Make it false for working of constraints
        fieldView.topAnchor.constraint(equalTo: topConstraints,constant: topSpace).isActive = isActive
        fieldView.leadingAnchor.constraint(equalTo: formBaseView.leadingAnchor,constant: leadingSpace).isActive = isActive
        fieldView.trailingAnchor.constraint(equalTo: formBaseView.trailingAnchor,constant: trailingSpace).isActive = isActive
        fieldView.heightAnchor.constraint(equalToConstant: height).isActive = isActive
    //  fieldView.layoutIfNeeded()
    

    //MARK: Setup MaxCharacter StackView function
    func setupMaxCharStackView(formStackView:UIStackView,topConstraints:NSLayoutAnchor<NSLayoutYAxisAnchor>,trailingSpace:CGFloat,topSpace:CGFloat,isActive:Bool)
        formStackView.translatesAutoresizingMaskIntoConstraints = false //Make it false for working of constraints
        formStackView.topAnchor.constraint(equalTo: topConstraints,constant: topSpace).isActive = isActive
        formStackView.trailingAnchor.constraint(equalTo: formBaseView.trailingAnchor,constant: trailingSpace).isActive = isActive
    

    //MARK: Setup StartDate EndDate StackView function
    func setupStartEndDateStackView(formStackView:UIStackView,topConstraints:NSLayoutAnchor<NSLayoutYAxisAnchor>,leadingSpace:CGFloat? = nil,trailingSpace:CGFloat,topSpace:CGFloat,isActive:Bool)

        formStackView.translatesAutoresizingMaskIntoConstraints = false //Make it false for working of constraints
        formStackView.topAnchor.constraint(equalTo: topConstraints,constant: topSpace).isActive = isActive
        formStackView.leadingAnchor.constraint(equalTo: formBaseView.leadingAnchor,constant: leadingSpace!).isActive = isActive
        formStackView.trailingAnchor.constraint(equalTo: formBaseView.trailingAnchor,constant: trailingSpace).isActive = isActive

    


【问题讨论】:

【参考方案1】:

问题是每次您点击按钮 1 的情况下触发,最终调用 setupInputFields 并导致重新添加可能与旧约束冲突的新约束,因此要么访问旧约束并删除它们,要么创建 2 个数组可能的变化和玩激活/停用

【讨论】:

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