Add tabView delegate

README.md

@@ -1,6 +1,4 @@
-<p align="center">
-  <img src="https://github.com/yysskk/Assets/blob/master/SwipeMenuViewController/Banner.png" width="800">
-</p>
+# SwipeMenuViewController
 
 [![Platform](http://img.shields.io/badge/platform-iOS-blue.svg?style=flat
 )](https://developer.apple.com/iphone/index.action)
@@ -11,7 +9,6 @@
 [![License](http://img.shields.io/badge/license-MIT-lightgrey.svg?style=flat
 )](http://mit-license.org)
 
-
 ## Overview
 SwipeMenuViewController provides `SwipeMenuView` and `SwipeMenuViewController`.
 This is very useful to build swipe-based paging UI.
@@ -255,6 +252,12 @@ func jump(to index: Int, animated: Bool)
 func willChangeOrientation()
 ```
 
+`TabView` has the following methods.
+```swift
+
+/// Reloads all `TabView` item views with the dataSource and refreshes the display.
+public func reloadData(options: SwipeMenuViewOptions.TabView? = nil, default defaultIndex: Int? = nil)
+```
 
 ### Protocols
 `SwipeMenuViewDataSource` and `SwipeMenuViewDelegate` has the following methods.
@@ -296,6 +299,16 @@ open weak var dataSource: SwipeMenuDataSource!
 private(set) var currentIndex
 ```
 
+`TabView` has the following properties.
+```swift
+
+// An object conforms `TabViewDelegate`. Provide views to populate the `TabView`.
+open weak var tabViewDelegate: TabViewDelegate?
+
+// An object conforms `TabViewDataSource`. Provide views and respond to `TabView` events.
+open weak var dataSource: TabViewDataSource?
+```
+
 ### Customization
 `SwipeMenuView` is customizable by designated options property when calling `reloadData()` method.
 Here are many properties of `SwipeMenuViewOptions` which you are able to customize it for your needs.

Sources/SwipeMenuView.swift

@@ -83,6 +83,8 @@ public struct SwipeMenuViewOptions {
 
         /// UnderlineView options
         public var underlineView = UndelineView()
+
+        public init() { }
     }
 
     public struct ContentScrollView {
@@ -148,10 +150,10 @@ public protocol SwipeMenuViewDataSource: class {
     /// Return the number of pages in `SwipeMenuView`.
     func numberOfPages(in swipeMenuView: SwipeMenuView) -> Int
 
-    /// Return strings to be displayed at the specified tag in `SwipeMenuView`.
+    /// Return strings to be displayed at the tab in `SwipeMenuView`.
     func swipeMenuView(_ swipeMenuView: SwipeMenuView, titleForPageAt index: Int) -> String
 
-    /// Return a ViewController to be displayed at the specified page in `SwipeMenuView`.
+    /// Return a ViewController to be displayed at the page in `SwipeMenuView`.
     func swipeMenuView(_ swipeMenuView: SwipeMenuView, viewControllerForPageAt index: Int) -> UIViewController
 }
 
@@ -169,6 +171,7 @@ open class SwipeMenuView: UIView {
         didSet {
             guard let tabView = tabView else { return }
             tabView.dataSource = self
+            tabView.tabViewDelegate = self
             addSubview(tabView)
             layout(tabView: tabView)
         }
@@ -294,7 +297,6 @@ open class SwipeMenuView: UIView {
 
         tabView = TabView(frame: CGRect(x: 0, y: 0, width: frame.width, height: options.tabView.height), options: options.tabView)
         tabView?.clipsToBounds = options.tabView.clipsToBounds
-        addTabItemGestures()
 
         contentScrollView = ContentScrollView(frame: CGRect(x: 0, y: options.tabView.height, width: frame.width, height: frame.height - options.tabView.height), default: defaultIndex, options: options.contentScrollView)
         contentScrollView?.clipsToBounds = options.contentScrollView.clipsToBounds
@@ -345,58 +347,29 @@ open class SwipeMenuView: UIView {
     }
 }
 
-// MARK: - TabViewDataSource
-
-extension SwipeMenuView: TabViewDataSource {
-
-    public func numberOfItems(in menuView: TabView) -> Int {
-        return dataSource?.numberOfPages(in: self) ?? 0
-    }
-
-    public func tabView(_ tabView: TabView, titleForItemAt index: Int) -> String? {
-        return dataSource?.swipeMenuView(self, titleForPageAt: index)
-    }
-}
+// MARK: - TabViewDelegate, TabViewDataSource
 
-// MARK: - GestureRecognizer
+extension SwipeMenuView: TabViewDelegate, TabViewDataSource {
 
-extension SwipeMenuView {
+    public func tabView(_ tabView: TabView, didSelectTabAt index: Int) {
 
-    fileprivate var tapGestureRecognizer: UITapGestureRecognizer {
-        let gestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(tapItemView(_:)))
-        gestureRecognizer.numberOfTapsRequired = 1
-        gestureRecognizer.cancelsTouchesInView = false
-        return gestureRecognizer
-    }
-
-    fileprivate func addTabItemGestures() {
-        tabView?.itemViews.forEach {
-            $0.addGestureRecognizer(tapGestureRecognizer)
-        }
-    }
-
-    @objc func tapItemView(_ recognizer: UITapGestureRecognizer) {
-
-        guard let itemView = recognizer.view as? TabItemView, let tabView = tabView, let index: Int = tabView.itemViews.index(of: itemView), let contentScrollView = contentScrollView else { return }
-        if currentIndex == index { return }
+        guard let contentScrollView = contentScrollView,
+            currentIndex != index else { return }
 
         isJumping = true
         jumpingToIndex = index
 
         contentScrollView.jump(to: index, animated: true)
-        moveTabItem(tabView: tabView, index: index)
 
         update(from: currentIndex, to: index)
     }
 
-    private func moveTabItem(tabView: TabView, index: Int) {
+    public func numberOfItems(in menuView: TabView) -> Int {
+        return dataSource?.numberOfPages(in: self) ?? 0
+    }
 
-        switch options.tabView.addition {
-        case .underline:
-            tabView.animateUnderlineView(index: index, completion: nil)
-        case .none:
-            tabView.update(index)
-        }
+    public func tabView(_ tabView: TabView, titleForItemAt index: Int) -> String? {
+        return dataSource?.swipeMenuView(self, titleForPageAt: index)
     }
 }
 

Sources/TabView.swift

@@ -1,15 +1,37 @@
 import UIKit
 
-public protocol TabViewDataSource {
+// MARK: - TabViewDelegate
 
+public protocol TabViewDelegate: class {
+
+    /// Called before selecting the tab.
+    func tabView(_ tabView: TabView, willSelectTabAt index: Int)
+
+    /// Called after selecting the tab.
+    func tabView(_ tabView: TabView, didSelectTabAt index: Int)
+}
+
+extension TabViewDelegate {
+    public func tabView(_ tabView: TabView, willSelectTabAt index: Int) {}
+
+    public func tabView(_ tabView: TabView, didSelectTabAt index: Int) {}
+}
+
+// MARK: - TabViewDataSource
+
+public protocol TabViewDataSource: class {
+
+    /// Return the number of Items in `TabView`.
     func numberOfItems(in tabView: TabView) -> Int
 
+    /// Return strings to be displayed at the tab in `TabView`.
     func tabView(_ tabView: TabView, titleForItemAt index: Int) -> String?
 }
 
 open class TabView: UIScrollView {
 
-    open var dataSource: TabViewDataSource!
+    open weak var tabViewDelegate: TabViewDelegate?
+    open weak var dataSource: TabViewDataSource?
 
     var itemViews: [TabItemView] = []
 
@@ -19,7 +41,7 @@ open class TabView: UIScrollView {
 
     fileprivate var currentIndex: Int = 0
 
-    fileprivate var options: SwipeMenuViewOptions.TabView = SwipeMenuViewOptions.TabView()
+    fileprivate(set) var options: SwipeMenuViewOptions.TabView = SwipeMenuViewOptions.TabView()
 
     private var leftMarginConstraint: NSLayoutConstraint = .init()
     private var widthConstraint: NSLayoutConstraint = .init()
@@ -37,7 +59,7 @@ open class TabView: UIScrollView {
     }
 
     open override func didMoveToSuperview() {
-        setup()
+        reloadData()
     }
 
     open override func layoutSubviews() {
@@ -57,22 +79,6 @@ open class TabView: UIScrollView {
         layoutIfNeeded()
     }
 
-    public func reset() {
-
-        itemViews.forEach { $0.removeFromSuperview() }
-        underlineView.removeFromSuperview()
-        containerView.removeFromSuperview()
-        itemViews = []
-    }
-
-    public func update(_ index: Int) {
-
-        if currentIndex == index { return }
-
-        currentIndex = index
-        updateSelectedItem(by: currentIndex)
-    }
-
     fileprivate func focus(on target: UIView, animated: Bool = true) {
 
         if options.style == .segmented { return }
@@ -99,16 +105,43 @@ open class TabView: UIScrollView {
 
     // MARK: - Setup
 
-    fileprivate func setup() {
+    /// Reloads all `TabView` item views with the dataSource and refreshes the display.
+    public func reloadData(options: SwipeMenuViewOptions.TabView? = nil,
+                       default defaultIndex: Int? = nil) {
+
+        if let options = options {
+            self.options = options
+        }
 
         reset()
 
-        guard dataSource.numberOfItems(in: self) > 0 else { return }
+        guard let dataSource = dataSource,
+            dataSource.numberOfItems(in: self) > 0 else { return }
 
         setupScrollView()
-        setupContainerView()
-        setupTabItemViews()
+        setupContainerView(dataSource: dataSource)
+        setupTabItemViews(dataSource: dataSource)
         setupUnderlineView()
+
+        if let defaultIndex = defaultIndex {
+            updateSelectedItem(by: defaultIndex)
+        }
+    }
+
+    func reset() {
+
+        itemViews.forEach { $0.removeFromSuperview() }
+        underlineView.removeFromSuperview()
+        containerView.removeFromSuperview()
+        itemViews = []
+    }
+
+    func update(_ index: Int) {
+
+        if currentIndex == index { return }
+
+        currentIndex = index
+        updateSelectedItem(by: currentIndex)
     }
 
     fileprivate func setupScrollView() {
@@ -123,7 +156,7 @@ open class TabView: UIScrollView {
         translatesAutoresizingMaskIntoConstraints = false
     }
 
-    fileprivate func setupContainerView() {
+    fileprivate func setupContainerView(dataSource: TabViewDataSource) {
 
         containerView.alignment = .leading
 
@@ -168,7 +201,7 @@ open class TabView: UIScrollView {
         addSubview(containerView)
     }
 
-    fileprivate func setupTabItemViews() {
+    fileprivate func setupTabItemViews(dataSource: TabViewDataSource) {
 
         itemViews = []
 
@@ -232,6 +265,7 @@ open class TabView: UIScrollView {
         }
 
         layout(containerView: containerView, containerWidth: xPosition)
+        addTabItemGestures()
         animateUnderlineView(index: currentIndex)
     }
 
@@ -320,7 +354,9 @@ extension TabView {
     }
 
     fileprivate func resetUnderlineViewPosition(index: Int) {
-        guard options.style == .segmented, dataSource.numberOfItems(in: self) > 0 else { return }
+        guard options.style == .segmented,
+            let dataSource = dataSource,
+            dataSource.numberOfItems(in: self) > 0 else { return }
         let adjustCellWidth: CGFloat
         if #available(iOS 11.0, *), options.isSafeAreaEnabled && safeAreaInsets != .zero {
             adjustCellWidth = (frame.width - options.margin * 2 - safeAreaInsets.left - safeAreaInsets.right) / CGFloat(dataSource.numberOfItems(in: self)) - options.underlineView.margin * 2
@@ -413,3 +449,42 @@ extension TabView {
         focus(on: currentItem, animated: false)
     }
 }
+
+// MARK: - GestureRecognizer
+
+extension TabView {
+
+    fileprivate var tapGestureRecognizer: UITapGestureRecognizer {
+        let gestureRecognizer = UITapGestureRecognizer(target: self, action: #selector(tapItemView(_:)))
+        gestureRecognizer.numberOfTapsRequired = 1
+        gestureRecognizer.cancelsTouchesInView = false
+        return gestureRecognizer
+    }
+
+    fileprivate func addTabItemGestures() {
+        itemViews.forEach {
+            $0.addGestureRecognizer(tapGestureRecognizer)
+        }
+    }
+
+    @objc func tapItemView(_ recognizer: UITapGestureRecognizer) {
+        guard let itemView = recognizer.view as? TabItemView,
+            let index: Int = itemViews.index(of: itemView),
+            currentIndex != index else { return }
+        tabViewDelegate?.tabView(self, willSelectTabAt: index)
+        moveTabItem(index: index)
+        update(index)
+        tabViewDelegate?.tabView(self, didSelectTabAt: index)
+    }
+
+    private func moveTabItem(index: Int) {
+
+        switch options.addition {
+        case .underline:
+            animateUnderlineView(index: index, completion: nil)
+        case .none:
+            update(index)
+        }
+    }
+}
+