Add safeAreaLayoutGuide support for iOS versions below 11.

Author: srdanrasic

Layoutless.podspec

@@ -1,12 +1,12 @@
 Pod::Spec.new do |s|
   s.name             = "Layoutless"
-  s.version          = "0.1.3"
+  s.version          = "0.1.4"
   s.summary          = "Write less UI code"
   s.description      = "Layoutless enables you to spend less time writing UI code. It provides a way to abstract common layout patterns and enable consistent styling approach."
   s.homepage         = "https://github.com/DeclarativeHub/Layoutless"
   s.license          = 'MIT'
   s.author           = { "Srdan Rasic" => "[email protected]" }
-  s.source           = { :git => "https://github.com/DeclarativeHub/Layoutless.git", :tag => "0.1.3" }
+  s.source           = { :git => "https://github.com/DeclarativeHub/Layoutless.git", :tag => "0.1.4" }
 
   s.ios.deployment_target       = '9.3'
   s.tvos.deployment_target      = '11.0'

Layoutless.xcodeproj/project.pbxproj

@@ -14,6 +14,8 @@
 		EC2870F0201E448100702624 /* Layout.swift in Sources */ = {isa = PBXBuildFile; fileRef = EC2870EF201E448100702624 /* Layout.swift */; };
 		EC2870F2201E44CE00702624 /* Layoutless+UIKit.swift in Sources */ = {isa = PBXBuildFile; fileRef = EC2870F1201E44CE00702624 /* Layoutless+UIKit.swift */; };
 		EC2870F4201E455A00702624 /* LayoutNode.swift in Sources */ = {isa = PBXBuildFile; fileRef = EC2870F3201E455A00702624 /* LayoutNode.swift */; };
+		EC8287712099D56F00E371EC /* UIView+iOS10.swift in Sources */ = {isa = PBXBuildFile; fileRef = EC8287702099D56F00E371EC /* UIView+iOS10.swift */; };
+		EC8287722099D56F00E371EC /* UIView+iOS10.swift in Sources */ = {isa = PBXBuildFile; fileRef = EC8287702099D56F00E371EC /* UIView+iOS10.swift */; };
 		ECCF2CE420246CD9008099DD /* Layoutless.swift in Sources */ = {isa = PBXBuildFile; fileRef = ECCF2CE320246CD9008099DD /* Layoutless.swift */; };
 		ECCF2CE620246DF0008099DD /* ChildNode.swift in Sources */ = {isa = PBXBuildFile; fileRef = ECCF2CE520246DF0008099DD /* ChildNode.swift */; };
 		ECCF2D9D2024C03A008099DD /* Label.swift in Sources */ = {isa = PBXBuildFile; fileRef = ECCF2D8D2024C03A008099DD /* Label.swift */; };
@@ -57,6 +59,7 @@
 		EC2870EF201E448100702624 /* Layout.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Layout.swift; sourceTree = "<group>"; };
 		EC2870F1201E44CE00702624 /* Layoutless+UIKit.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "Layoutless+UIKit.swift"; sourceTree = "<group>"; };
 		EC2870F3201E455A00702624 /* LayoutNode.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = LayoutNode.swift; sourceTree = "<group>"; };
+		EC8287702099D56F00E371EC /* UIView+iOS10.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = "UIView+iOS10.swift"; sourceTree = "<group>"; };
 		ECCF2CE320246CD9008099DD /* Layoutless.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = Layoutless.swift; sourceTree = "<group>"; };
 		ECCF2CE520246DF0008099DD /* ChildNode.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = ChildNode.swift; sourceTree = "<group>"; };
 		ECCF2D8D2024C03A008099DD /* Label.swift */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.swift; path = Label.swift; sourceTree = "<group>"; };
@@ -141,6 +144,7 @@
 				ECCF2CE520246DF0008099DD /* ChildNode.swift */,
 				ECCF2CE320246CD9008099DD /* Layoutless.swift */,
 				EC2870F1201E44CE00702624 /* Layoutless+UIKit.swift */,
+				EC8287702099D56F00E371EC /* UIView+iOS10.swift */,
 			);
 			path = Layout;
 			sourceTree = "<group>";
@@ -300,6 +304,7 @@
 				EC2870EE201E446900702624 /* LayoutProtocol.swift in Sources */,
 				ECCF2DA22024C03A008099DD /* TextField.swift in Sources */,
 				ECCF2DA32024C03A008099DD /* ImageView.swift in Sources */,
+				EC8287712099D56F00E371EC /* UIView+iOS10.swift in Sources */,
 				ECCF2D9D2024C03A008099DD /* Label.swift in Sources */,
 				EC2870F4201E455A00702624 /* LayoutNode.swift in Sources */,
 				ECCF2D9E2024C03A008099DD /* ViewController.swift in Sources */,
@@ -325,6 +330,7 @@
 				ECCF2E0F20274F82008099DD /* Anchorable.swift in Sources */,
 				ECCF2E0E20274F82008099DD /* Length.swift in Sources */,
 				ECCF2E1220274F82008099DD /* Layout.swift in Sources */,
+				EC8287722099D56F00E371EC /* UIView+iOS10.swift in Sources */,
 				ECCF2E1020274F82008099DD /* LayoutNode.swift in Sources */,
 				ECCF2E1820274F88008099DD /* Label.swift in Sources */,
 				ECCF2E1A20274F88008099DD /* TextField.swift in Sources */,

Layoutless/Info.plist

@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>0.1.3</string>
+	<string>0.1.4</string>
 	<key>CFBundleVersion</key>
 	<string>$(CURRENT_PROJECT_VERSION)</string>
 	<key>NSPrincipalClass</key>

Sources/Layout/Layoutless.swift

@@ -51,7 +51,7 @@ extension LayoutProtocol where LayoutNode: Anchorable {
                 if #available(iOS 11.0, *), safeArea {
                     layout(parent.safeAreaLayoutGuide, node)
                 } else {
-                    layout(parent, node)
+                    layout(parent.___safeAreaLayoutGuide, node)
                 }
             }
         }

Sources/Layout/UIView+iOS10.swift

@@ -0,0 +1,34 @@
+//
+//  UIView+iOS10.swift
+//  Layoutless
+//
+//  Created by Srdan Rasic on 02/05/2018.
+//  Copyright © 2018 Declarative Hub. All rights reserved.
+//
+
+import UIKit
+
+extension UIView {
+
+    private struct AssociatedKeys {
+        static var safeAreaLayoutGuide = "safeAreaLayoutGuide"
+    }
+
+    internal var ___safeAreaLayoutGuide: UILayoutGuide {
+        get {
+            let layoutGuide = objc_getAssociatedObject(self, &AssociatedKeys.safeAreaLayoutGuide) as? UILayoutGuide
+            if let layoutGuide = layoutGuide {
+                return layoutGuide
+            } else {
+                let layoutGuide = UILayoutGuide()
+                addLayoutGuide(layoutGuide)
+                NSLayoutConstraint.activate([
+                    layoutGuide.leadingAnchor.constraint(equalTo: leadingAnchor),
+                    layoutGuide.trailingAnchor.constraint(equalTo: trailingAnchor)
+                ])
+                objc_setAssociatedObject(self, &AssociatedKeys.safeAreaLayoutGuide, layoutGuide, .OBJC_ASSOCIATION_RETAIN_NONATOMIC)
+                return layoutGuide
+            }
+        }
+    }
+}

Sources/Views/View.swift

@@ -60,4 +60,19 @@ open class View: UIView {
     open var subviewsLayout: AnyLayout {
         return EmptyLayout()
     }
+
+    open override func didMoveToSuperview() {
+        super.didMoveToSuperview()
+
+        guard let superview = superview else { return }
+
+        if #available(iOS 11.0, *) {
+            // safeAreaLayoutGuide is already available
+        } else {
+            NSLayoutConstraint.activate([
+                ___safeAreaLayoutGuide.topAnchor.constraint(equalTo: superview.___safeAreaLayoutGuide.topAnchor),
+                ___safeAreaLayoutGuide.bottomAnchor.constraint(equalTo: superview.___safeAreaLayoutGuide.bottomAnchor)
+            ])
+        }
+    }
 }

Sources/Views/ViewController.swift

@@ -38,6 +38,13 @@ open class ViewController: UIViewController {
 
     open override func viewDidLoad() {
         super.viewDidLoad()
+
+        if #available(iOS 11.0, *) {
+            // safeAreaLayoutGuide is already available
+        } else {
+            setupSafeAreaLayoutGuideFallback()
+        }
+
         defineLayout()
     }
 
@@ -51,4 +58,11 @@ open class ViewController: UIViewController {
     open var subviewsLayout: AnyLayout {
         return EmptyLayout()
     }
+
+    private func setupSafeAreaLayoutGuideFallback() {
+        NSLayoutConstraint.activate([
+            view.___safeAreaLayoutGuide.topAnchor.constraint(equalTo: topLayoutGuide.bottomAnchor),
+            view.___safeAreaLayoutGuide.bottomAnchor.constraint(equalTo: bottomLayoutGuide.topAnchor)
+        ])
+    }
 }