Add Image Slideshow delegate

Author: zvonicek

Example/ImageSlideshow/ViewController.swift

@@ -37,9 +37,7 @@ class ViewController: UIViewController {
 
         // optional way to show activity indicator during image load (skipping the line will show no activity indicator)
         slideshow.activityIndicator = DefaultActivityIndicator()
-        slideshow.currentPageChanged = { page in
-            print("current page:", page)
-        }
+        slideshow.delegate = self
 
         // can be used with other sample sources as `afNetworkingSource`, `alamofireSource` or `sdWebImageSource` or `kingfisherSource`
         slideshow.setImageInputs(localSource)
@@ -52,5 +50,8 @@ class ViewController: UIViewController {
         let fullScreenController = slideshow.presentFullScreenController(from: self)
         // set the activity indicator for full screen controller (skipping the line will show no activity indicator)
         fullScreenController.slideshow.activityIndicator = DefaultActivityIndicator(style: .white, color: nil)
+extension ViewController: ImageSlideshowDelegate {
+    func imageSlideshow(_ imageSlideshow: ImageSlideshow, didChangeCurrentPageTo page: Int) {        
+        print("current page:", page)
     }
 }

ImageSlideshow/Classes/Core/ImageSlideshow.swift

@@ -7,6 +7,27 @@
 
 import UIKit
 
+@objc
+/// The delegate protocol informing about image slideshow state changes
+public protocol ImageSlideshowDelegate: class {
+    /// Tells the delegate that the current page has changed
+    ///
+    /// - Parameters:
+    ///   - imageSlideshow: image slideshow instance
+    ///   - page: new page
+    @objc optional func imageSlideshow(_ imageSlideshow: ImageSlideshow, didChangeCurrentPageTo page: Int)
+
+    /// Tells the delegate that the slideshow will begin dragging
+    ///
+    /// - Parameter imageSlideshow: image slideshow instance
+    @objc optional func imageSlideshowWillBeginDragging(_ imageSlideshow: ImageSlideshow)
+
+    /// Tells the delegate that the slideshow did end decelerating
+    ///
+    /// - Parameter imageSlideshow: image slideshow instance
+    @objc optional func imageSlideshowDidEndDecelerating(_ imageSlideshow: ImageSlideshow)
+}
+
 /** 
     Used to represent position of the Page Control
     - hidden: Page Control is hidden
@@ -94,10 +115,14 @@ open class ImageSlideshow: UIView {
         didSet {
             if oldValue != currentPage {
                 currentPageChanged?(currentPage)
+                delegate?.imageSlideshow?(self, didChangeCurrentPageTo: currentPage)
             }
         }
     }
 
+    /// Delegate called on image slideshow state change
+    open weak var delegate: ImageSlideshowDelegate?
+
     /// Called on each currentPage change
     open var currentPageChanged: ((_ page: Int) -> ())?
 
@@ -494,11 +519,13 @@ extension ImageSlideshow: UIScrollViewDelegate {
 
         setTimerIfNeeded()
         willBeginDragging?()
+        delegate?.imageSlideshowWillBeginDragging?(self)
     }
 
     open func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) {
         setCurrentPageForScrollViewPage(primaryVisiblePage)
         didEndDecelerating?()
+        delegate?.imageSlideshowDidEndDecelerating?(self)
     }
 
     open func scrollViewDidScroll(_ scrollView: UIScrollView) {