[FEATURE] Support Priority

- SnapLayout now supports priority with all snaps!
- Added test for priority
- Updated Example project priority cell with update

Example/Podfile.lock

@@ -1,5 +1,5 @@
 PODS:
-  - SnapLayout (1.6.2)
+  - SnapLayout (1.8.0)
 
 DEPENDENCIES:
   - SnapLayout (from `../`)
@@ -9,7 +9,7 @@ EXTERNAL SOURCES:
     :path: "../"
 
 SPEC CHECKSUMS:
-  SnapLayout: 387502e5b6acbd2f12308fab94425907a87866c1
+  SnapLayout: bef399cd9d9cf1959e249edd58eadc60836862dc
 
 PODFILE CHECKSUM: 15badb46d75d789f8e26d30c1acb2aa5249c4ced
 

Example/SnapLayout.xcodeproj/xcshareddata/xcschemes/SnapLayout_ExampleTests.xcscheme

@@ -10,7 +10,8 @@
       buildConfiguration = "Debug"
       selectedDebuggerIdentifier = "Xcode.DebuggerFoundation.Debugger.LLDB"
       selectedLauncherIdentifier = "Xcode.DebuggerFoundation.Launcher.LLDB"
-      shouldUseLaunchSchemeArgsEnv = "YES">
+      shouldUseLaunchSchemeArgsEnv = "YES"
+      codeCoverageEnabled = "YES">
       <Testables>
          <TestableReference
             skipped = "NO">

Example/SnapLayout/AdjacentHorizontalTableViewCell.swift

@@ -27,7 +27,7 @@ internal final class AdjacentHorizontalTableViewCell: TitleTableViewCell {
     fileprivate func setupLabels() {
         let leadingLabel = Style.subtitleLabel(text: "Leading Label")
         contentView.addSubview(leadingLabel)
-        leadingLabel.snap(constants: leadingLabelConfig)
+        leadingLabel.snap(config: leadingLabelConfig)
 
         let trailingLabel = Style.subtitleLabel(text: "Trailing Label")
         contentView.addSubview(trailingLabel)

Example/SnapLayout/Base.lproj/LaunchScreen.xib

@@ -1,8 +1,12 @@
-<?xml version="1.0" encoding="UTF-8" standalone="no"?>
-<document type="com.apple.InterfaceBuilder3.CocoaTouch.XIB" version="3.0" toolsVersion="6214" systemVersion="14A314h" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" launchScreen="YES" useTraitCollections="YES">
+<?xml version="1.0" encoding="UTF-8"?>
+<document type="com.apple.InterfaceBuilder3.CocoaTouch.XIB" version="3.0" toolsVersion="12120" systemVersion="16E195" targetRuntime="iOS.CocoaTouch" propertyAccessControl="none" useAutolayout="YES" launchScreen="YES" useTraitCollections="YES" colorMatched="YES">
+    <device id="retina4_7" orientation="portrait">
+        <adaptation id="fullscreen"/>
+    </device>
     <dependencies>
-        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="6207"/>
+        <plugIn identifier="com.apple.InterfaceBuilder.IBCocoaTouchPlugin" version="12088"/>
         <capability name="Constraints with non-1.0 multipliers" minToolsVersion="5.1"/>
+        <capability name="documents saved in the Xcode 8 format" minToolsVersion="8.0"/>
     </dependencies>
     <objects>
         <placeholder placeholderIdentifier="IBFilesOwner" id="-1" userLabel="File's Owner"/>
@@ -24,7 +28,7 @@
                     <nil key="highlightedColor"/>
                 </label>
             </subviews>
-            <color key="backgroundColor" white="1" alpha="1" colorSpace="custom" customColorSpace="calibratedWhite"/>
+            <color key="backgroundColor" red="1" green="1" blue="1" alpha="1" colorSpace="custom" customColorSpace="sRGB"/>
             <constraints>
                 <constraint firstItem="kId-c2-rCX" firstAttribute="centerY" secondItem="iN0-l3-epB" secondAttribute="bottom" multiplier="1/3" constant="1" id="5cJ-9S-tgC"/>
                 <constraint firstAttribute="centerX" secondItem="kId-c2-rCX" secondAttribute="centerX" id="Koa-jz-hwk"/>

Example/SnapLayout/Info.plist

@@ -20,5 +20,7 @@
 	<string>$(CURRENT_PROJECT_VERSION)</string>
 	<key>NSPrincipalClass</key>
 	<string></string>
+	<key>UILaunchStoryboardName</key>
+	<string>LaunchScreen</string>
 </dict>
 </plist>

Example/SnapLayout/PriorityTableViewCell.swift

@@ -7,6 +7,7 @@
 //
 
 import UIKit
+import SnapLayout
 
 /// Displays rectangle view with a constraint whose priority is updated
 class PriorityTableViewCell: TitleTableViewCell {
@@ -27,14 +28,11 @@ class PriorityTableViewCell: TitleTableViewCell {
         contentView.addSubview(rectangleView)
 
         // Snaps square view by pinning to all 4 sides (activated constraints)
-        // Then creates an inactive height constraint whose priority is updated before being activated through `squareViewSnapManager`
+        // Then creates a height constraint whose priority is updated and then activated
         // Updating height priority to avoid following runtime warning
         // http://stackoverflow.com/questions/28410309/strange-uiview-encapsulated-layout-height-error
-        let squareViewSnapManager = rectangleView
-            .snap(top: 48, leading: 16, bottom: 16, trailing: 16)
-            .snap(height: 40, isActive: false)
-        squareViewSnapManager.height?.priority = 999
-        squareViewSnapManager.height?.isActive = true
+        rectangleView.snap(top: 48, leading: 16, bottom: 16, trailing: 16)
+                     .snap(height: 40, priority: UILayoutPriorityDefaultHigh)
 
         let circleView = UIView()
         circleView.backgroundColor = .green

Example/SnapLayout/ViewController.swift

@@ -38,7 +38,7 @@ internal final class ViewController: UIViewController {
         tableView.allowsSelection = false
         tableView.tableFooterView = UIView(frame: .zero)
         view.addSubview(tableView)
-        tableView.snap(constants: .zero) // snaps top, leading, bottom, and trailing
+        tableView.snap(config: .zero) // snaps top, leading, bottom, and trailing
     }
 
 }

Example/SnapLayout_ExampleTests/SnapLayoutTests.swift

@@ -170,5 +170,17 @@ class SnapLayoutTests: BaseTestCase {
         XCTAssertEqual(snapManagerInActive.top!.constant, topConstant)
         XCTAssertEqual(snapManagerInActive.top!.multiplier, 1.0)
     }
+
+    /// Tests priority for a snap
+    func testPriority() {
+        let snapManagerDefaultPriority = childView.snapHeight(to: childView2, multiplier: 0.5)
+        XCTAssertEqual(snapManagerDefaultPriority.height!.priority, LayoutPriorityRequired)
+
+        let snapManagerHighPriority = childView.snapWidth(to: childView2, priority: UILayoutPriorityDefaultHigh)
+        XCTAssertEqual(snapManagerHighPriority.width!.priority, UILayoutPriorityDefaultHigh)
+
+        let snapManagerLowPriority = childView.snap(top: 100, priority: UILayoutPriorityDefaultLow)
+        XCTAssertEqual(snapManagerLowPriority.top!.priority, UILayoutPriorityDefaultLow)
+    }
 
 }

Example/SnapLayout_ExampleTests/SnapManagerTests.swift

@@ -90,7 +90,7 @@ class SnapManagerTests: BaseTestCase {
         let containerView = UIView()
         containerView.addSubview(containerViewSubview)
         containerView.addSubview(otherView)
-        let snapManager = containerViewSubview.snap(to: otherView, constants: .zero)
+        let snapManager = containerViewSubview.snap(to: otherView, config: .zero)
         XCTAssertEqual(containerViewSubview.translatesAutoresizingMaskIntoConstraints, false)
         XCTAssertNotNil(snapManager.top)
         XCTAssertEqual(snapManager.top!.constant, 0)
@@ -124,7 +124,7 @@ class SnapManagerTests: BaseTestCase {
                                     height: heightConstant,
                                     centerX: centerXConstant,
                                     centerY: centerYConstant)
-        let snapManager = childView.snap(constants: snapConfig)
+        let snapManager = childView.snap(config: snapConfig)
         XCTAssertEqual(childView.translatesAutoresizingMaskIntoConstraints, false)
         XCTAssertNotNil(snapManager.top)
         XCTAssertEqual(snapManager.top!.constant, topConstant)
@@ -162,7 +162,7 @@ class SnapManagerTests: BaseTestCase {
                                     width: widthConstant,
                                     height: heightConstant)
         let centerConfig = SnapConfig(centerX: centerXConstant, centerY: centerYConstant)
-        let snapManager = childView.snap(constants: snapConfig)
+        let snapManager = childView.snap(config: snapConfig)
                                    .snap(config: centerConfig)
         XCTAssertNotNil(snapManager.top)
         XCTAssertEqual(snapManager.top!.constant, topConstant)

README.md

@@ -69,15 +69,15 @@ github "sp71/SnapLayout"
 
 ### [`Methods`](SnapLayout/Classes/SnapLayout.swift)
 ```swift
-func snap(to view: View? = nil, top: CGFloat? = nil, leading: CGFloat? = nil, bottom: CGFloat? = nil, trailing: CGFloat? = nil, width: CGFloat? = nil, height: CGFloat? = nil, centerX: CGFloat? = nil, centerY: CGFloat? = nil, isActive: Bool = true) -> SnapManager
-func snap(to view: View? = nil, constants: SnapConfig, isActive: Bool = true) -> SnapManager
-func snapWidth(to view: View, multiplier: CGFloat = 1, isActive: Bool = true) -> SnapManager
-func snapHeight(to view: View, multiplier: CGFloat = 1, isActive: Bool = true) -> SnapManager
-func snap(size: CGSize, isActive: Bool = true) -> SnapManager
-func snap(trailingView: View, constant: CGFloat = 0, isActive: Bool = true) -> SnapManager
-func snap(leadingView: View, constant: CGFloat = 0, isActive: Bool = true) -> SnapManager
-func snap(bottomView: View, constant: CGFloat = 0, isActive: Bool = true) -> SnapManager
-func snap(topView: View, constant: CGFloat = 0, isActive: Bool = true) -> SnapManager
+func snap(to view: View? = nil, top: CGFloat? = nil, leading: CGFloat? = nil, bottom: CGFloat? = nil, trailing: CGFloat? = nil, width: CGFloat? = nil, height: CGFloat? = nil, centerX: CGFloat? = nil, centerY: CGFloat? = nil, priority: LayoutPriority = LayoutPriorityRequired, isActive: Bool = true) -> SnapManager
+func snap(to view: View? = nil, config: SnapConfig, priority: LayoutPriority = LayoutPriorityRequired, isActive: Bool = true) -> SnapManager
+func snapWidth(to view: View, multiplier: CGFloat = 1, priority: LayoutPriority = LayoutPriorityRequired, isActive: Bool = true) -> SnapManager
+func snapHeight(to view: View, multiplier: CGFloat = 1, priority: LayoutPriority = LayoutPriorityRequired, isActive: Bool = true) -> SnapManager
+func snap(size: CGSize, priority: LayoutPriority = LayoutPriorityRequired, isActive: Bool = true) -> SnapManager
+func snap(trailingView: View, constant: CGFloat = 0, priority: LayoutPriority = LayoutPriorityRequired, isActive: Bool = true) -> SnapManager
+func snap(leadingView: View, constant: CGFloat = 0, priority: LayoutPriority = LayoutPriorityRequired, isActive: Bool = true) -> SnapManager
+func snap(bottomView: View, constant: CGFloat = 0, priority: LayoutPriority = LayoutPriorityRequired, isActive: Bool = true) -> SnapManager
+func snap(topView: View, constant: CGFloat = 0, priority: LayoutPriority = LayoutPriorityRequired, isActive: Bool = true) -> SnapManager
 ```
 
 ### Sample Code
@@ -102,12 +102,26 @@ print(snapManager.top?.constant)    # 8.0
 print(snapManager.height?.constant) # 0.5
 ```
 Snap calls may also be chained and will continue to return a `SnapManager`.
-### Constants
+### Config
 A `SnapConfig ` struct is also available where a developer may list all of their constraint constants beforehand and provide this type to the snap method argument.
 
 ```swift
 let config = SnapConfig(top: 50, leading: 50, trailing: 50, width: 30, centerX: 0)
-button.snap(constants: config)
+button.snap(config: config)
+```
+
+### Priority
+SnapLayout assumes required priority (same default as Apple) unless otherwise specified for those created constraints.
+
+```swift
+button1.snap(trailingView: button2, constant: 8, priority: UILayoutPriorityDefaultLow)
+```
+
+In the following example, the top, leading, bottom, and trailing constraint all have a priority of required; however, the height constraint has a `UILayoutPriorityDefaultHigh` priority. That's it!
+
+```swift
+rectangleView.snap(top: 48, leading: 16, bottom: 16, trailing: 16)
+             .snap(height: 40, priority: UILayoutPriorityDefaultHigh)
 ```
 
 ### To Activate or not to Activate

SnapLayout.podspec

@@ -8,7 +8,7 @@
 
 Pod::Spec.new do |s|
   s.name             = 'SnapLayout'
-  s.version          = '1.7.0'
+  s.version          = '1.8.0'
   s.summary          = 'Concise API for iOS Auto Layout'
 
 s.description  = <<-DESC

SnapLayout/Classes/Aliases.swift

@@ -9,7 +9,15 @@
 #if os(iOS) || os(tvOS)
     /// Allows views to be OS independent while leveraging existing code
     public typealias View = UIView
+    /// Allows layout priority to be OS independent while leveraging existing code
+    public typealias LayoutPriority = UILayoutPriority
+    /// Allows layout priority required to be OS independent while leveraging existing code
+    public var LayoutPriorityRequired = UILayoutPriorityRequired
 #elseif os(OSX)
     /// Allows views to be OS independent while leveraging existing code
     public typealias View = NSView
+    /// Allows layout priority to be OS independent while leveraging existing code
+    public typealias LayoutPriority = NSLayoutPriority
+    /// Allows layout priority required to be OS independent while leveraging existing code
+    public var LayoutPriorityRequired = NSLayoutPriorityRequired
 #endif