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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