Merge pull request #20 from NSMyself/fix/layoutGuide

Fix layout guide issue

Author: pedrommcarrasco

Constrictor.podspec

@@ -1,7 +1,7 @@
 Pod::Spec.new do |s|
   s.swift_version = "4.2"
   s.name         = "Constrictor"
-  s.version      = "4.1.0"
+  s.version      = "4.1.1"
   s.summary      = "🐍 AutoLayout's µFramework"
 
   s.description  = "(Boe) Constrictor's AutoLayout µFramework with the goal of simplying your constraints by reducing the amount of code you have to write."

Constrictor/Constrictor/Factory/LayoutItemFactory.swift

@@ -10,109 +10,115 @@ import Foundation
 
 // MARK: - LayoutItemFactory
 struct LayoutItemFactory {
-
+    
+    // MARK: Constants
+    private enum Constants {
+        
+        static let fakeSafeAreaIdentifier = "fakeSafeArea"
+    }
+    
     /**
      Converts a set of attributes, elements and constant into two LayoutItems
-
+     
      - parameters:
      - firstElement: Optional Constrictable's to extract NSLayoutConstraint.Attribute from.
      - secondElement: Optional Constrictable's to extract NSLayoutConstraint.Attribute from.
      - firstAttribute: ConstrictorAttributor from the first element.
      - secondAttribute: ConstrictorAttributor from the second element.
      - constant: Constant to be applied to the first element.
-
+     
      - returns:
      Tuple containing an HeadLayoutImte & TailLayoutItem (starting anchor and ending anchor).
      */
     static func makeLayoutItems(firstElement: Constrictable?, secondElement: Constrictable?,
                                 firstAttribute: ConstrictorAttribute, secondAttribute: ConstrictorAttribute,
                                 constant: Constant) -> (head: HeadLayoutItem, tail: TailLayoutItem) {
-
+        
         let firstItem = layoutItem(for: firstElement, attribute: firstAttribute, constant: constant)
         let secondItem = layoutItem(for: secondElement, attribute: secondAttribute, constant: constant)
-
+        
         return (firstItem.asHead, secondItem.asTail)
     }
-
+    
     /**
      Converts an attribute, element and constant into a LayoutItem
-
+     
      - parameters:
      - element: Optional Constrictable's to extract NSLayoutConstraint.Attribute from.
      - attribute: ConstrictorAttributor from the  element.
      - constant: Constant to be applied.
-
+     
      - returns:
      HeadLayoutItem
      */
-
+    
     static func makeLayoutItem(element: Constrictable?,
                                attribute: ConstrictorAttribute,
                                constant: Constant) -> HeadLayoutItem {
-
+        
         return layoutItem(for: element, attribute: attribute, constant: constant).asHead
     }
 }
 
 
 // MARK: - Decision Maker
 private extension LayoutItemFactory {
-
-
+    
+    
     static func layoutItem(for element: Constrictable?,
                            attribute: ConstrictorAttribute,
                            constant: Constant) -> LayoutItem {
-
+        
         var item = LayoutItem()
-
+        
         if let view = element as? UIView {
             item = layoutItem(view: view, with: attribute, and: constant)
         } else if let viewController = element as? UIViewController {
             item = layoutItem(viewController: viewController, with: attribute, and: constant)
         } else if let layoutGuide = element as? UILayoutGuide {
             item = layoutItem(layoutGuide: layoutGuide, with: attribute, and: constant)
         }
-
+        
         return item
     }
-
+    
     static func layoutItem(layoutGuide: UILayoutGuide,
                            with attribute: ConstrictorAttribute,
                            and constantStruct: Constant) -> LayoutItem {
-
+        
         return buildLayoutItem(for: attribute, with: constantStruct, safeArea: layoutGuide)
     }
-
+    
     static func layoutItem(view: UIView,
                            with attribute: ConstrictorAttribute,
                            and constantStruct: Constant) -> LayoutItem {
-
+        
         let safeArea: Any
-
+        
         if #available(iOS 11.0, *), ConstrictorAttribute.guidedAttributes.contains(attribute) {
             safeArea = view.safeAreaLayoutGuide
         } else {
             safeArea = view
         }
-
+        
         return buildLayoutItem(for: attribute, with: constantStruct, safeArea: safeArea)
     }
-
+    
     static func layoutItem(viewController: UIViewController,
                            with constrictorAttribute: ConstrictorAttribute,
                            and constantStruct: Constant) -> LayoutItem {
-
+        
         let safeArea: Any
         let atLeastiOS11: Bool
-
+        
         if #available(iOS 11.0, *), ConstrictorAttribute.guidedAttributes.contains(constrictorAttribute) {
             safeArea = viewController.view.safeAreaLayoutGuide
             atLeastiOS11 = true
         } else {
             safeArea = viewController.view
             atLeastiOS11 = false
         }
-
+        
         return buildLayoutItem(for: constrictorAttribute,
                                with: constantStruct,
                                viewController: viewController,
@@ -123,115 +129,136 @@ private extension LayoutItemFactory {
 
 // MARK: - Builder
 private extension LayoutItemFactory {
-
+    
     static func buildLayoutItem(for constrictorAttribute: ConstrictorAttribute,
                                 with constantStruct: Constant,
                                 viewController: UIViewController? = nil,
                                 atLeastiOS11: Bool? = nil,
                                 safeArea: Any) -> LayoutItem {
-
+        
         let attribute: NSLayoutConstraint.Attribute
         let constant: CGFloat
         var element = safeArea
-
+        
         switch constrictorAttribute {
         case .top:
             attribute = .top
             constant = constantStruct.top
-
+            
         case .topGuide:
             attribute = .top
             constant = constantStruct.top
-
-            if let atLeastiOS11 = atLeastiOS11, !atLeastiOS11, let vc = viewController { element = vc.topLayoutGuide
+            
+            if let atLeastiOS11 = atLeastiOS11, !atLeastiOS11,
+                let vc = viewController, let fakeSafeArea = safeLayoutGuide(for: vc) {
+                
+                element = fakeSafeArea
+                
             } else { element = safeArea }
-
+            
         case .bottom:
             attribute = .bottom
             constant = -constantStruct.bottom
-
+            
         case .bottomGuide:
             attribute = .bottom
             constant = -constantStruct.bottom
-
-            if let atLeastiOS11 = atLeastiOS11, !atLeastiOS11, let vc = viewController { element = vc.bottomLayoutGuide
+            
+            if let atLeastiOS11 = atLeastiOS11, !atLeastiOS11,
+                let vc = viewController, let fakeSafeArea = safeLayoutGuide(for: vc) {
+                
+                element = fakeSafeArea
+                
             } else { element = safeArea }
-
+            
         case .right, .rightGuide:
             attribute = .right
             constant = -constantStruct.right
-
+            
         case .left, .leftGuide:
             attribute = .left
             constant = constantStruct.left
-
+            
         case .leading, .leadingGuide:
             attribute = .leading
             constant = constantStruct.leading
-
+            
         case .trailing, .trailingGuide:
             attribute = .trailing
             constant = -constantStruct.trailing
-
+            
         case .centerX:
             attribute = .centerX
             constant = constantStruct.x
-
+            
         case .centerXGuide:
             attribute = .centerX
             constant = constantStruct.x
-
-            if let atLeastiOS11 = atLeastiOS11, !atLeastiOS11, let vc = viewController {
-                element = safeLayoutGuide(for: vc)
+            
+            if let atLeastiOS11 = atLeastiOS11, !atLeastiOS11,
+                let vc = viewController, let fakeSafeArea = safeLayoutGuide(for: vc) {
+                
+                element = fakeSafeArea
+                
             } else { element = safeArea }
-
+            
         case .centerY:
             attribute = .centerY
             constant = constantStruct.y
-
+            
         case .centerYGuide:
             attribute = .centerY
             constant = constantStruct.y
-
-            if let atLeastiOS11 = atLeastiOS11, !atLeastiOS11, let vc = viewController {
-                element = safeLayoutGuide(for: vc)
+            
+            if let atLeastiOS11 = atLeastiOS11, !atLeastiOS11,
+                let vc = viewController, let fakeSafeArea = safeLayoutGuide(for: vc) {
+                
+                element = fakeSafeArea
+                
             } else { element = safeArea }
-
+            
         case .width:
             attribute = .width
             constant = constantStruct.width
-
+            
         case .height:
             attribute = .height
             constant = constantStruct.height
-
+            
         case .none:
             attribute = .notAnAttribute
             constant = 0.0
         }
-
+        
         return LayoutItem(element: element, attribute: attribute, constant: constant)
     }
 }
 
 // MARK: - Utils
 private extension LayoutItemFactory {
-
+    
     /**
-     Get an UILayoutGuide pinned to the viewController's safe edges. 
-
+     Get an UILayoutGuide pinned to the viewController's safe edges.
+     
      - parameters:
      - viewController: UIViewController to get an UILayoutGuide pinned its edges
-
+     
      - returns:
      Safe UILayoutGuide.
      */
-
-    static func safeLayoutGuide(for viewController: UIViewController) -> UILayoutGuide {
-
+    
+    static func safeLayoutGuide(for viewController: UIViewController) -> UILayoutGuide? {
+        
+        let fakeSafeArea = viewController.view.layoutGuides
+            .filter(isFakeSafeArea)
+            .first
+        
+        guard fakeSafeArea == nil else { return fakeSafeArea }
+        
         let layoutGuide = UILayoutGuide()
+        layoutGuide.identifier = Constants.fakeSafeAreaIdentifier
         viewController.view.addLayoutGuide(layoutGuide)
-
+        
         NSLayoutConstraint.activate(
             [
                 NSLayoutConstraint(
@@ -256,7 +283,11 @@ private extension LayoutItemFactory {
                 )
             ]
         )
-
+        
         return layoutGuide
     }
+    
+    static func isFakeSafeArea(_ layoutGuide: UILayoutGuide) -> Bool {
+        return layoutGuide.identifier == Constants.fakeSafeAreaIdentifier
+    }
 }