adjusting line animation on TabBar changes

Sources/iOS/TabBar.swift

@@ -78,14 +78,21 @@ open class TabBar: Bar {
     }
     
     /// An enum that determines the tab bar style.
-    open var tabBarStyle = TabBarStyle.normal {
+    open var tabBarStyle = TabBarStyle.scrollable {
         didSet {
             layoutSubviews()
         }
     }
     
     /// A reference to the scroll view when the tab bar style is scrollable.
-    open fileprivate(set) var scrollView: UIScrollView!
+    open let scrollView = UIScrollView()
+    
+    /// Does the scroll view bounce. 
+    open var isScrollBounceEnabled = true {
+        didSet {
+            scrollView.bounces = true
+        }
+    }
     
     /// A delegation reference.
     open weak var delegate: TabBarDelegate?
@@ -270,11 +277,7 @@ open class TabBar: Bar {
         
         layoutDivider()
         
-        let buttonsWidth = buttons.reduce(0) {
-            $0 + $1.sizeThatFits(CGSize(width: .greatestFiniteMagnitude, height: contentView.height)).width + interimSpace
-        }
-        
-        if .scrollable == tabBarStyle && buttonsWidth > p {
+        if .scrollable == tabBarStyle {
             scrollView.frame = CGRect(x: l, y: 0, width: p, height: height)
             
             var w: CGFloat = 0
@@ -288,14 +291,14 @@ open class TabBar: Bar {
                 w += width
             }
             
-            scrollView.contentSize = CGSize(width: buttonsWidth, height: height)
-            scrollView.addSubview(line)
+            scrollView.contentSize = CGSize(width: w, height: height)
         } else {
             contentView.grid.axis.columns = buttons.count
             centerViews = buttons
-            addSubview(line)
         }
         
+        addSubview(line)
+        
         updateSelectionLine()
 	}
     
@@ -354,8 +357,6 @@ extension TabBar {
     
     /// Prepares the scroll view. 
     fileprivate func prepareScrollView() {
-        scrollView = UIScrollView()
-        scrollView.bounces = false
         scrollView.isPagingEnabled = false
         scrollView.showsVerticalScrollIndicator = false
         scrollView.showsHorizontalScrollIndicator = false

Sources/iOS/TabsController.swift

@@ -32,12 +32,7 @@ import UIKit
 
 fileprivate var TabItemKey: UInt8 = 0
 
-open class TabItem: FlatButton {
-    open override func prepare() {
-        super.prepare()
-        pulseAnimation = .none
-    }
-}
+open class TabItem: FlatButton {}
 
 @objc(TabBarAlignment)
 public enum TabBarAlignment: Int {
@@ -95,6 +90,7 @@ open class TabsController: UIViewController {
             
             prepareTabBar()
             prepareContainer()
+            prepareViewControllers()
             layoutSubviews()
         }
     }
@@ -111,7 +107,7 @@ open class TabsController: UIViewController {
     }
     
     /// The transition type used during a transition.
-    open var transitionType = MotionTransitionType.autoReverse(presenting: .fade)
+    open var motionTransitionType = MotionTransitionType.fade
     
     /**
      An initializer that initializes the object with a NSCoder object.
@@ -150,8 +146,7 @@ open class TabsController: UIViewController {
     open func layoutSubviews() {
         layoutTabBar()
         layoutContainer()
-        
-        viewControllers[selectedIndex].view.frame.size = container.bounds.size
+        layoutViewController(at: selectedIndex)
     }
     
     /**
@@ -165,10 +160,7 @@ open class TabsController: UIViewController {
         view.contentScaleFactor = Screen.scale
         prepareContainer()
         prepareTabBar()
-        
-        for i in 0..<viewControllers.count {
-            prepareViewController(at: i)
-        }
+        prepareViewControllers()
     }
 }
 
@@ -224,6 +216,21 @@ extension TabsController {
         view.addSubview(container)
     }
     
+    /// Prepares all the view controllers. 
+    fileprivate func prepareViewControllers() {
+        let n = viewControllers.count
+        
+        for i in 0..<n {
+            guard i != selectedIndex else {
+                continue
+            }
+            
+            prepareViewController(at: i)
+        }
+        
+        prepareViewController(at: selectedIndex)
+    }
+    
     /**
      Loads a view controller based on its index in the viewControllers Array
      and adds it as a child view controller.
@@ -267,7 +274,7 @@ extension TabsController {
             container.height = view.height
         }
         
-        container.width = view.bounds.width
+        container.width = view.width
     }
     
     /// Layout the TabBar.
@@ -291,6 +298,11 @@ extension TabsController {
             v.isHidden = true
         }
     }
+    
+    /// Layout the view controller at the given index.
+    fileprivate func layoutViewController(at index: Int) {
+        viewControllers[index].view.frame.size = container.bounds.size
+    }
 }
 
 extension TabsController {
@@ -343,10 +355,12 @@ extension TabsController {
         let tvc = viewControllers[i]
         
         tvc.view.frame.size = container.bounds.size
-        tvc.motionModalTransitionType = transitionType
+        tvc.motionModalTransitionType = motionTransitionType
         
         Motion.shared.transition(from: fvc, to: tvc, in: container)
         
         selectedIndex = i
+        
+        tabBar?.select(at: selectedIndex)
     }
 }