Digital ACT-191 ONEAPP-6830 story: update position when scroll thumb drag / on move forward / backward

VDS/Components/CarouselScrollbar/CarouselScrollbar.swift

@@ -112,6 +112,8 @@ open class CarouselScrollbar: View {
     /// Allows a unique id to be passed into the thumb and track of the thumb(scrubber).
     open var scrubberId: Int?  { didSet { setNeedsUpdate() } }
     
+    /// A callback when the scrubber position changes. Passes parameters (position).
+    open var onScrubberDidChange: ((Int) -> Void)?
     
     //--------------------------------------------------
     // MARK: - Private Properties
@@ -241,29 +243,32 @@ open class CarouselScrollbar: View {
     // MARK: - Private Methods
     //--------------------------------------------------
     func onMoveBackward() {
-        thumbView.frame.origin.x = thumbView.frame.origin.x - CGFloat(actualThumbWidth)
+        position = (position ?? 1) - 1
-        updateActiveOverlays()
+        scrollThumbToPosition(position)
     }
     
     func onMoveForward() {
-        thumbView.frame.origin.x = thumbView.frame.origin.x + CGFloat(actualThumbWidth)
+        position = (position ?? 1) + 1
-        updateActiveOverlays()
+        scrollThumbToPosition(position)
     }
-
+    
+    // Drag scrollbar thumb to move it to the left or right.
+    // Upon releases of drag, the scrollbar thumb snaps to the closest full position and the scrollbar returns to original size without delay.
     @objc func onScrubberDrag(_ sender: UIPanGestureRecognizer) {
         let translation = sender.translation(in: thumbView)
         if sender.state == UIGestureRecognizer.State.began {
             trayOriginalCenter = thumbView.center
         } else if sender.state == UIGestureRecognizer.State.changed {
-            let movePositions = Int (ceil (Double(translation.x) / Double(actualThumbWidth)))
+            let draggedPositions = Int (ceil (Double(translation.x) / Double(actualThumbWidth)))
-            setThumb(at: (position ?? 1) + movePositions)
+            setThumb(at: (position ?? 1) + draggedPositions)
         }
         else if sender.state == UIGestureRecognizer.State.cancelled || sender.state == UIGestureRecognizer.State.ended {
-            let movePositions = Int (ceil (Double(translation.x) / Double(actualThumbWidth)))
+            let draggedPositions = Int (ceil (Double(translation.x) / Double(actualThumbWidth)))
-            position = (position ?? 1) + movePositions
+            position = (((position ?? 1) + draggedPositions) < 1) ? 1 : ((position ?? 1) + draggedPositions)
         }
     }
     
+    // Move the scrollbar thumb to the left while tapping on the left side of the scrubber.
     @objc func onThumbTouchStart(_ gesture: UILongPressGestureRecognizer) {
         if gesture.state == .began {
             leftActiveOverlay.backgroundColor = activeOverlayColorConfiguration.getColor(self)
@@ -274,12 +279,11 @@ open class CarouselScrollbar: View {
         } else if gesture.state == .ended {
             leftActiveOverlay.backgroundColor = .clear
             leftActiveOverlay.layer.opacity = defaultOpacity
-            DispatchQueue.main.asyncAfter(deadline: .now() + .milliseconds(100)) { [weak self] in
+            self.onMoveBackward()
-                self?.onMoveBackward()
-            }
         }
     }
     
+    // Move the scrollbar thumb to the right while tapping on the right side of the scrubber.
     @objc func onThumbTouchEnd(_ gesture: UILongPressGestureRecognizer) {
         if gesture.state == .began {
             rightActiveOverlay.backgroundColor = activeOverlayColorConfiguration.getColor(self)
@@ -290,12 +294,12 @@ open class CarouselScrollbar: View {
         } else if gesture.state == .ended {
             rightActiveOverlay.backgroundColor = .clear
             rightActiveOverlay.layer.opacity = defaultOpacity
-            DispatchQueue.main.asyncAfter(deadline: .now() + .milliseconds(100)) { [weak self] in
+            self.onMoveForward()
-                self?.onMoveForward()
-            }
         }
     }
     
+    // Minimum thumb width applied
+    // Incomplete set moves a shorter distance than the standard increment value.
     private func setThumbWidth() {
         let width = (Float(trackViewWidth) / Float(numberOfSlides ?? 1)) * Float(_selectedLayout.value)
         actualThumbWidth = (width > Float(trackViewWidth)) ? Float(trackViewWidth) : width
@@ -306,6 +310,7 @@ open class CarouselScrollbar: View {
         updateActiveOverlays()
     }
     
+    // Update active overlay frames according to thumb position.
     private func updateActiveOverlays() {
         // adjusting thumb position if it goes beyond trackView.
         let thumbPosition = thumbView.frame.origin.x + thumbView.frame.size.width
@@ -331,6 +336,7 @@ open class CarouselScrollbar: View {
     private func scrollThumbToPosition(_ position: Int?) {
         DispatchQueue.main.asyncAfter(deadline: .now() + .milliseconds(100)) { [weak self] in
             self?.setThumb(at: position)
+            self?.onScrubberDidChange?(position ?? 1)
         }
     }