TabsController fixes, added delegation, and programmatical selection of view controller

Material.podspec

 Pod::Spec.new do |s|
     s.name = 'Material'
-    s.version = '2.10.0'
+    s.version = '2.10.1'
     s.license = 'BSD-3-Clause'
     s.summary = 'A Material Design library for creating beautiful applications.'
     s.homepage = 'http://materialswift.com'

Sources/Info.plist

@@ -15,7 +15,7 @@
 	<key>CFBundlePackageType</key>
 	<string>FMWK</string>
 	<key>CFBundleShortVersionString</key>
-	<string>2.10.0</string>
+	<string>2.10.1</string>
 	<key>CFBundleSignature</key>
 	<string>????</string>
 	<key>CFBundleVersion</key>

Sources/iOS/Switch.swift

@@ -498,7 +498,7 @@ extension Switch {
 
 extension Switch {
     /**
-     Handle the TouchUpOutside and TouchCancel events.
+     Handle the TouchUpOutside and TouchCancel moments.
      - Parameter sender: A UIButton.
      - Parameter event: A UIEvent.
      */

Sources/iOS/TabBar.swift

@@ -46,20 +46,23 @@ public enum TabBarLineAlignment: Int {
 @objc(TabBarDelegate)
 public protocol TabBarDelegate {
     /**
-     A delegation method that is executed when the tabItem will trigger the
-     animation to the next tab.
+     A delegation method that is executed to determine if the TabBar should
+     transition to the next tab.
      - Parameter tabBar: A TabBar.
      - Parameter tabItem: A TabItem.
+     - Returns: A Boolean.
      */
     @objc
-    optional func tabBar(tabBar: TabBar, willSelect tabItem: TabItem)
+    optional func tabBar(tabBar: TabBar, shouldSelect tabItem: TabItem) -> Bool
     
     /**
-     A delegation method that is executed to determine if the tabItem should
-     transition to the next tab.
+     A delegation method that is executed when the tabItem will trigger the
+     animation to the next tab.
+     - Parameter tabBar: A TabBar.
+     - Parameter tabItem: A TabItem.
      */
     @objc
-    optional func tabBar(tabBar: TabBar, shouldSelect tabItem: TabItem) -> Bool
+    optional func tabBar(tabBar: TabBar, willSelect tabItem: TabItem)
     
     /**
      A delegation method that is executed when the tabItem did complete the
@@ -123,7 +126,7 @@ open class TabBar: Bar {
     open weak var delegate: TabBarDelegate?
     
     /// The currently selected tabItem.
-    open fileprivate(set) var selectedTabItem: TabItem?
+    open internal(set) var selectedTabItem: TabItem?
     
     /// A preset wrapper around tabItems contentEdgeInsets.
     open var tabItemsContentEdgeInsetsPreset: EdgeInsetsPreset {

Sources/iOS/TabsController.swift

@@ -63,6 +63,35 @@ extension UIViewController {
     }
 }
 
+@objc(TabsControllerDelegate)
+public protocol TabsControllerDelegate {
+    /**
+     A delegation method that is executed to determine if the TabsController should
+     transition to the next view controller.
+     - Parameter tabBar: A TabsController.
+     - Parameter tabItem: A TabItem.
+     - Returns: A Boolean.
+     */
+    @objc
+    optional func tabsController(tabsController: TabsController, shouldSelect viewController: UIViewController) -> Bool
+    
+    /**
+     A delegation method that is executed when the view controller will transitioned to.
+     - Parameter tabsController: A TabsController.
+     - Parameter viewController: A UIViewController.
+     */
+    @objc
+    optional func tabsController(tabsController: TabsController, willSelect viewController: UIViewController)
+    
+    /**
+     A delegation method that is executed when the view controller has been transitioned to.
+     - Parameter tabsController: A TabsController.
+     - Parameter viewController: A UIViewController.
+     */
+    @objc
+    optional func tabsController(tabsController: TabsController, didSelect viewController: UIViewController)
+}
+
 open class TabsController: TransitionController {
     /**
      A Display value to indicate whether or not to
@@ -79,6 +108,9 @@ open class TabsController: TransitionController {
     @IBInspectable
     open let tabBar = TabBar()
     
+    /// A delegation reference.
+    open weak var delegate: TabsControllerDelegate?
+    
     /// An Array of UIViewControllers.
     open var viewControllers: [UIViewController] {
         didSet {
@@ -153,6 +185,18 @@ open class TabsController: TransitionController {
     }
     
     open override func transition(to viewController: UIViewController, completion: ((Bool) -> Void)?) {
+        transition(to: viewController, isTriggeredByUserInteraction: false, completion: completion)
+    }
+}
+
+fileprivate extension TabsController {
+    /**
+     Transitions to the given view controller.
+     - Parameter to viewController: A UIViewController.
+     - Parameter isTriggeredByUserInteraction: A Boolean.
+     - Parameter completion: An optional completion block.
+     */
+    func transition(to viewController: UIViewController, isTriggeredByUserInteraction: Bool, completion: ((Bool) -> Void)?) {
         guard let fvc = rootViewController else {
             return
         }
@@ -173,6 +217,10 @@ open class TabsController: TransitionController {
         default:break
         }
         
+        if isTriggeredByUserInteraction {
+            delegate?.tabsController?(tabsController: self, willSelect: tvc)
+        }
+        
         view.isUserInteractionEnabled = false
         Motion.shared.transition(from: fvc, to: tvc, in: container) { [weak self, tvc = tvc, isAuto = isAuto, completion = completion] (isFinished) in
             guard let s = self else {
@@ -185,7 +233,12 @@ open class TabsController: TransitionController {
             
             s.rootViewController = tvc
             s.view.isUserInteractionEnabled = true
+            
             completion?(isFinished)
+            
+            if isTriggeredByUserInteraction {
+                s.delegate?.tabsController?(tabsController: s, didSelect: tvc)
+            }
         }
     }
 }
@@ -244,6 +297,7 @@ fileprivate extension TabsController {
         }
         
         tabBar.tabItems = tabItems
+        tabBar.selectedTabItem = tabItems[selectedIndex]
     }
 }
 
@@ -296,6 +350,34 @@ fileprivate extension TabsController {
     }
 }
 
+extension TabsController {
+    /**
+     Transitions to the view controller that is at the given index.
+     - Parameter at index: An Int.
+     */
+    open func select(at index: Int) {
+        guard index != selectedIndex else {
+            return
+        }
+        
+        Motion.delay(0) { [weak self] in
+            guard let s = self else {
+                return
+            }
+            
+            s.tabBar.select(at: index)
+            
+            s.transition(to: s.viewControllers[index], isTriggeredByUserInteraction: false) { [weak self] (isFinished) in
+                guard isFinished else {
+                    return
+                }
+                
+                self?.selectedIndex = index
+            }
+        }
+    }
+}
+
 extension TabsController: TabBarDelegate {
     @objc
     open func tabBar(tabBar: TabBar, willSelect tabItem: TabItem) {
@@ -311,7 +393,11 @@ extension TabsController: TabBarDelegate {
             return
         }
         
-        transition(to: viewControllers[i]) { [weak self] (isFinished) in
+        guard !(false == delegate?.tabsController?(tabsController: self, shouldSelect: viewControllers[i])) else {
+            return
+        }
+        
+        transition(to: viewControllers[i], isTriggeredByUserInteraction: true) { [weak self] (isFinished) in
             guard isFinished else {
                 return
             }