SwiftLint support + overall project improvements

.swiftlint.yml

@@ -0,0 +1,21 @@
+# rule identifiers to exclude from running
+disabled_rules:
+  - line_length
+
+# some rules are only opt-in
+opt_in_rules:
+# Find all the available rules by running:
+# swiftlint rules
+
+
+# paths to include during linting. `--path` is ignored if present.
+included:
+
+
+# paths to ignore during linting. Takes precedence over `included`.
+excluded:
+
+
+# configurable rules can be customized from this configuration file
+# binary rules can set their severity level  
+force_cast: warning

.travis.yml

@@ -18,11 +18,4 @@ before_install:
     - xcodebuild -version
     - xcodebuild -showsdks
 
-    # This command will fix Travis CI duplicated simulators build issue
-    # happening while using Xcode 8.2 + iOS simulator 10.2 configuration. Be
-    # sure to check GitHub issue #7031
-    # (https://github.com/travis-ci/travis-ci/issues/7031) for updates and, as
-    # soon as the Travis team fix the issue, remove this line.
-    - xcrun simctl delete D0257C83-DB81-4567-93EC-4C6DF23DC24C
-
 script: xcodebuild -project "$PROJECT" -scheme "$SCHEME" -sdk "$SDK" -destination "$DESTINATION" -configuration Debug test | xcpretty -f `xcpretty-travis-formatter` && exit ${PIPESTATUS[0]}

Classes/GLCollectionTableViewCell.swift

@@ -30,35 +30,58 @@
 import UIKit
 
 class GLIndexedCollectionViewFlowLayout: UICollectionViewFlowLayout {
-	var paginatedScroll: Bool?
+	fileprivate var paginatedScroll: Bool?
 
 	override func awakeFromNib() {
 		super.awakeFromNib()
 	}
 
 	override func targetContentOffset(forProposedContentOffset proposedContentOffset: CGPoint, withScrollingVelocity velocity: CGPoint) -> CGPoint {
+		// If the UICollectionView has paginatedScroll set to false there is no
+		// need to apply any pagination logic, so we simply return the current
+		// proposedContentOffset coordinates.
 		guard paginatedScroll == true else {
 			return CGPoint(x: proposedContentOffset.x, y: 0)
 		}
 
+		// It's not a bad idea to shield us for some strange cases where the
+		// UICollectionView won't be there for any reason, since it comes in an
+		// Optional flavor. If the UICollectionView won't be available we return
+		// the current proposedContentOffset coordinates and exit.
+		guard let collectionView: UICollectionView = collectionView else {
+			return CGPoint(x: proposedContentOffset.x, y: 0)
+		}
+
+		let scannerFrame: CGRect = CGRect(x: proposedContentOffset.x,
+		                                  y: 0,
+		                                  width: collectionView.bounds.width,
+		                                  height: collectionView.bounds.height)
+
+		// If there is no UICollectionViewLayoutAttributes for the given
+		// scannerFrame there is no reason to calculate a paginated layout for
+		// it, so we the current proposedContentOffset coordinates.
+		guard let layoutAttributes: [UICollectionViewLayoutAttributes] = super.layoutAttributesForElements(in: scannerFrame) else {
+			return CGPoint(x: proposedContentOffset.x, y: 0)
+		}
+
 		// To make paginated scrolling work fine this CGFloat below MUST be
 		// equal to the value set in the insetForSectionAt method of
 		// UICollectionView's UICollectionViewDelegate Flow Layout.
 		let collectionViewInsets: CGFloat = 10.0
 
-		// Since UICollectionViewFlowLayout proposedContentOffset coordinates
+		// Since UICollectionViewFlowLayout's proposedContentOffset coordinates
 		// won't take count of any UICollectionView UIEdgeInsets values we need
 		// to fix it by adding collectionViewInsets to the .x coordinate.
 		//
-		// Note: This will only cover horizontal scrolling and pagination, if you
-		// need vertical pagination replace the .x coordinate with .y and update
-		// collectionViewInsets value with the appropriate one.
+		// Note: This will only cover horizontal scrolling and pagination, if
+		// you need vertical pagination replace the .x coordinate with .y and
+		// update collectionViewInsets value with the appropriate one.
 		let proposedXCoordWithInsets: CGFloat = proposedContentOffset.x + collectionViewInsets
 
 		// We now create a variable and we assign a very high CGFloat to it (a
-		// big number here is needed to cover very large
-		// UICollectionViewContentSize cases). This var will hold the needed
-		// horizontal adjustment to make the UICollectionView paginate scroll.
+		// to cover very large UICollectionViewContentSize cases).
+		// This var will hold the needed horizontal adjustment to make the
+		// UICollectionView paginate scroll.
 		var offsetCorrection: CGFloat = .greatestFiniteMagnitude
 
 		// Now we loop through all the different layout attributes of the
@@ -67,22 +90,11 @@ class GLIndexedCollectionViewFlowLayout: UICollectionViewFlowLayout {
 		// cell which needs the least offsetCorrection value: it will mean that
 		// it's the first cell on the left of the screen which will give
 		// pagination.
-		for layoutAttribute: UICollectionViewLayoutAttributes in super.layoutAttributesForElements(in: CGRect(x: proposedContentOffset.x, y: 0, width: collectionView!.bounds.width, height: collectionView!.bounds.height))! {
-			// layoutAttributesForElements may contain all sort of layout
+		layoutAttributes.forEach { (layoutAttribute) in
+			// UICollectionViewLayoutAttributes may contain all sort of layout
 			// attributes so we need to check if it belongs to a
 			// UICollectionViewCell, otherwise logic won't work.
 			if layoutAttribute.representedElementCategory == .cell {
-				// Since UICollectionViewFlowLayout's UICollectionView comes in
-				// an Optional flavour and we will need to get it's frame size
-				// down below, it's not a bad idea to shield us from those very
-				// strange cases in which the UICollectionView won't be there
-				// (for whatever reason) and exit the loop since it is useless
-				// to calculate an offsetCorrection for a non-existent
-				// UICollectionView.
-				guard let collectionView = collectionView else {
-					break
-				}
-
 				// To accurately calculate the offsetCorrection we will check
 				// only the cells contained in one half of UICollectionView's
 				// width, following the scrolling direction. The check will be
@@ -91,7 +103,7 @@ class GLIndexedCollectionViewFlowLayout: UICollectionViewFlowLayout {
 				let discardableScrollingElementsFrame: CGFloat = collectionView.contentOffset.x + (collectionView.frame.size.width / 2)
 
 				if (layoutAttribute.center.x <= discardableScrollingElementsFrame && velocity.x > 0) || (layoutAttribute.center.x >= discardableScrollingElementsFrame && velocity.x < 0) {
-					continue
+					return
 				}
 
 				if abs(layoutAttribute.frame.origin.x - proposedXCoordWithInsets) < abs(offsetCorrection) {
@@ -160,7 +172,7 @@ class GLCollectionTableViewCell: UITableViewCell {
 		collectionFlowLayout.scrollDirection = .horizontal
 
 		collectionView = GLIndexedCollectionView(frame: .zero, collectionViewLayout: collectionFlowLayout)
-		collectionView.register(UINib(nibName: "GLIndexedCollectionViewCell", bundle: nil), forCellWithReuseIdentifier: "collectionViewCellID")
+		collectionView.register(UINib(nibName: "GLIndexedCollectionViewCell", bundle: nil), forCellWithReuseIdentifier: GLIndexedCollectionViewCell.identifier)
 		collectionView.backgroundColor = .white
 		collectionView.showsHorizontalScrollIndicator = false
 		collectionView.showsVerticalScrollIndicator = false

Classes/GLIndexedCollectionViewCell.swift

@@ -30,6 +30,8 @@
 import UIKit
 
 class GLIndexedCollectionViewCell: UICollectionViewCell {
+	static let identifier: String = "collectionViewCellID"
+
 	override func awakeFromNib() {
         super.awakeFromNib()
         // Initialization code

Classes/GLTableCollectionViewController.swift

@@ -29,14 +29,14 @@
 
 import UIKit
 
-class GLTableCollectionViewController: UITableViewController, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {
-	// This string constant will be the cellIdentifier for the UITableViewCells
-	// holding the UICollectionView, it's important to append "_section#" to it
-	// so we can understand which cell is the one we are looking for in the
-	// debugger. Look in UITableView's data source cellForRowAt method for more
-	// explanations about the UITableViewCell reuse handling.
-	let tableCellID: String = "tableViewCellID_section_#"
-	let collectionCellID: String = "collectionViewCellID"
+final class GLTableCollectionViewController: UITableViewController, UICollectionViewDataSource, UICollectionViewDelegate, UICollectionViewDelegateFlowLayout {
+	// This static string constant will be the cellIdentifier for the
+	// UITableViewCells holding the UICollectionView, it's important to append
+	// "_section#" to it so we can understand which cell is the one we are
+	// looking for in the debugger. Look in UITableView's data source
+	// cellForRowAt method for more explanations about the UITableViewCell reuse
+	// handling.
+	static let tableCellID: String = "tableViewCellID_section_#"
 
 	let numberOfSections: Int = 20
 	let numberOfCollectionsForRow: Int = 1
@@ -66,7 +66,7 @@ class GLTableCollectionViewController: UITableViewController, UICollectionViewDa
 				let randomGreen: CGFloat = CGFloat(arc4random_uniform(256))
 				let randomBlue: CGFloat = CGFloat(arc4random_uniform(256))
 
-				if (randomRed == 255.0 && randomGreen == 255.0 && randomBlue == 255.0) {
+				if randomRed == 255.0 && randomGreen == 255.0 && randomBlue == 255.0 {
 					randomRed = CGFloat(arc4random_uniform(128))
 				}
 
@@ -109,10 +109,10 @@ class GLTableCollectionViewController: UITableViewController, UICollectionViewDa
 		// will have a different UICollectionView with UICollectionViewCells in
 		// it and UITableView reuse won't work as expected giving back wrong
 		// cells.
-		var cell: GLCollectionTableViewCell? = tableView.dequeueReusableCell(withIdentifier: tableCellID + indexPath.section.description) as? GLCollectionTableViewCell
+		var cell: GLCollectionTableViewCell? = tableView.dequeueReusableCell(withIdentifier: GLTableCollectionViewController.tableCellID + indexPath.section.description) as? GLCollectionTableViewCell
 
 		if cell == nil {
-			cell = GLCollectionTableViewCell(style: .default, reuseIdentifier: tableCellID + indexPath.section.description)
+			cell = GLCollectionTableViewCell(style: .default, reuseIdentifier: GLTableCollectionViewController.tableCellID + indexPath.section.description)
 
 			// Configure the cell...
 			cell!.selectionStyle = .none
@@ -126,6 +126,8 @@ class GLTableCollectionViewController: UITableViewController, UICollectionViewDa
 		return "Section: " + section.description
 	}
 
+	// MARK: <UITableView Delegate>
+
 	override func tableView(_ tableView: UITableView, heightForRowAt indexPath: IndexPath) -> CGFloat {
 		return 88
 	}
@@ -138,8 +140,6 @@ class GLTableCollectionViewController: UITableViewController, UICollectionViewDa
 		return 0.0001
 	}
 
-	// MARK: <UITableView Delegate>
-
 	override func tableView(_ tableView: UITableView, willDisplay cell: UITableViewCell, forRowAt indexPath: IndexPath) {
 		guard let cell: GLCollectionTableViewCell = cell as? GLCollectionTableViewCell else {
 			return
@@ -159,10 +159,16 @@ class GLTableCollectionViewController: UITableViewController, UICollectionViewDa
 	}
 
 	func collectionView(_ collectionView: UICollectionView, cellForItemAt indexPath: IndexPath) -> UICollectionViewCell {
-		let cell: GLIndexedCollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: collectionCellID, for: indexPath) as! GLIndexedCollectionViewCell
+		guard let cell: GLIndexedCollectionViewCell = collectionView.dequeueReusableCell(withReuseIdentifier: GLIndexedCollectionViewCell.identifier, for: indexPath) as? GLIndexedCollectionViewCell else {
+			fatalError("UICollectionViewCell must be of GLIndexedCollectionViewCell type")
+		}
+
+		guard let indexedCollectionView: GLIndexedCollectionView = collectionView as? GLIndexedCollectionView else {
+			fatalError("UICollectionView must be of GLIndexedCollectionView type")
+		}
 
 		// Configure the cell...
-		cell.backgroundColor = colorsDict[(collectionView as! GLIndexedCollectionView).indexPath.section]?[indexPath.row]
+		cell.backgroundColor = colorsDict[indexedCollectionView.indexPath.section]?[indexPath.row]
 
 		return cell
 	}
@@ -175,7 +181,7 @@ class GLTableCollectionViewController: UITableViewController, UICollectionViewDa
 	let collectionRightInset: CGFloat = 10
 
 	func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, insetForSectionAt section: Int) -> UIEdgeInsets {
-		return UIEdgeInsetsMake(collectionTopInset, collectionLeftInset, collectionBottomInset, collectionRightInset)
+		return UIEdgeInsets(top: collectionTopInset, left: collectionLeftInset, bottom: collectionBottomInset, right: collectionRightInset)
 	}
 
 	func collectionView(_ collectionView: UICollectionView, layout collectionViewLayout: UICollectionViewLayout, sizeForItemAt indexPath: IndexPath) -> CGSize {
@@ -197,17 +203,17 @@ class GLTableCollectionViewController: UITableViewController, UICollectionViewDa
 	// MARK: <UICollectionView Delegate>
 
 	func collectionView(_ collectionView: UICollectionView, didSelectItemAt indexPath: IndexPath) {
-		
+
 	}
 
-    /*
-    // MARK: <Navigation>
+	/*
+	// MARK: <Navigation>
 
-    // In a storyboard-based application, you will often want to do a little
+	// In a storyboard-based application, you will often want to do a little
 	// preparation before navigation
-    override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
-        // Get the new view controller using segue.destinationViewController.
-        // Pass the selected object to the new view controller.
-    }
-    */
+	override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
+		// Get the new view controller using segue.destinationViewController.
+		// Pass the selected object to the new view controller.
+	}
+	*/
 }

GLTableCollectionView.xcodeproj/project.pbxproj

@@ -115,6 +115,7 @@
 				747CF8F51DE6EB010051A5FF /* Sources */,
 				747CF8F61DE6EB010051A5FF /* Frameworks */,
 				747CF8F71DE6EB010051A5FF /* Resources */,
+				EF73511D1E8E9B5800F73EDB /* SwiftLint */,
 			);
 			buildRules = (
 			);
@@ -205,6 +206,23 @@
 		};
 /* End PBXResourcesBuildPhase section */
 
+/* Begin PBXShellScriptBuildPhase section */
+		EF73511D1E8E9B5800F73EDB /* SwiftLint */ = {
+			isa = PBXShellScriptBuildPhase;
+			buildActionMask = 2147483647;
+			files = (
+			);
+			inputPaths = (
+			);
+			name = SwiftLint;
+			outputPaths = (
+			);
+			runOnlyForDeploymentPostprocessing = 0;
+			shellPath = /bin/sh;
+			shellScript = "if which swiftlint >/dev/null; then\n    swiftlint\nelse\n    echo \"warning: SwiftLint not installed, download from https://github.com/realm/SwiftLint\"\nfi";
+		};
+/* End PBXShellScriptBuildPhase section */
+
 /* Begin PBXSourcesBuildPhase section */
 		747CF8F51DE6EB010051A5FF /* Sources */ = {
 			isa = PBXSourcesBuildPhase;

GLTableCollectionView/AppDelegate.swift

@@ -30,7 +30,7 @@
 import UIKit
 
 @UIApplicationMain
-class AppDelegate: UIResponder, UIApplicationDelegate {
+final class AppDelegate: UIResponder, UIApplicationDelegate {
 	var window: UIWindow?
 
 	func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

GLTableCollectionView/Info.plist

@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>APPL</string>
 	<key>CFBundleShortVersionString</key>
-	<string>1.69</string>
+	<string>1.70</string>
 	<key>CFBundleVersion</key>
 	<string>1</string>
 	<key>LSRequiresIPhoneOS</key>

GLTableCollectionViewTests/GLTableCollectionViewTests.swift

@@ -58,17 +58,14 @@ class GLTableCollectionViewTests: XCTestCase {
 		XCTAssertGreaterThan(tableCollectionView.numberOfCollectionItems, 0,
 		                     "numberOfCollectionItems was: \(tableCollectionView.numberOfCollectionItems)\nThere must be at least one GLIndexedCollectionViewCell")
 
-		XCTAssertNotEqual(tableCollectionView.tableCellID, "",
-		                  "tableCellID was: \(tableCollectionView.tableCellID)\nUITableViewCell's cellIdentifier must not be empty")
+		XCTAssertNotEqual(GLTableCollectionViewController.tableCellID, "",
+		                  "tableCellID was: \(GLTableCollectionViewController.tableCellID)\nUITableViewCell's cellIdentifier must not be empty")
 
-		XCTAssertTrue(tableCollectionView.tableCellID.hasSuffix("_section_#"),
-		              "tableCellID was: \(tableCollectionView.tableCellID)\nUITableViewCell's cellIdentifier must end with section number suffix")
+		XCTAssertTrue(GLTableCollectionViewController.tableCellID.hasSuffix("_section_#"),
+		              "tableCellID was: \(GLTableCollectionViewController.tableCellID)\nUITableViewCell's cellIdentifier must end with section number suffix")
 
-		XCTAssertTrue((tableCollectionView.tableCellID.components(separatedBy: "#").count - 1) == 1,
-		              "tableCellID was: \(tableCollectionView.tableCellID)\nUITableViewCell's cellIdentifier must contain only one # in it")
-
-		XCTAssertNotEqual(tableCollectionView.collectionCellID, "",
-		                  "The cellIdentifier for the UICollectionCells should not be empty")
+		XCTAssertTrue((GLTableCollectionViewController.tableCellID.components(separatedBy: "#").count - 1) == 1,
+		              "tableCellID was: \(GLTableCollectionViewController.tableCellID)\nUITableViewCell's cellIdentifier must contain only one # in it")
 	}
 
 	func testRandomColorsGeneration() {
@@ -106,7 +103,7 @@ class GLTableCollectionViewTests: XCTestCase {
 
 		for tableViewCell: GLCollectionTableViewCell in visibleCells as! [GLCollectionTableViewCell] {
 			XCTAssertTrue(Int(tableViewCell.reuseIdentifier!.components(separatedBy: "#").last!)! >= 0,
-			              "GLCollectionTableViewCell cellIdentifier was: \(tableViewCell.reuseIdentifier)\nGLCollectionTableViewCell's cellIdentifier must end with a positive integer")
+			              "GLCollectionTableViewCell cellIdentifier was: \(String(describing: tableViewCell.reuseIdentifier))\nGLCollectionTableViewCell's cellIdentifier must end with a positive integer")
 		}
 	}
 

README.md

@@ -50,6 +50,7 @@ var paginationEnabled: Bool = true
 - Xcode 8.0+
 - Swift 3.0+
 - iOS 8.0+
+- [SwiftLint](https://github.com/realm/SwiftLint) (Optional, but _highly_ suggested)
 
 ## Note
 GLTableCollectionView is written using Swift 3.0 so it would only support iOS 8.0+ due to Swift 3 language compatibility, if you use Swift 2.0 in your project or you need iOS 7.0+ compatibility GLTableCollectionView will work too, but you **must** convert `UITableView` and `UICollectionView` Data Source and Delegate methods signatures before building your code or Xcode won't compile.