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| // | |
| // ScrollViewObserver.swift | |
| // IndoChat | |
| // | |
| // Copyright © 2022 PT. ICE Messenger Indonesia. All rights reserved. | |
| // | |
| import UIKit | |
| // https://stackoverflow.com/questions/26953559/in-swift-how-do-i-have-a-uiscrollview-subclass-that-has-an-internal-and-externa | |
| class ScrollViewObserver: NSObject { | |
| // MARK: - Private Properties | |
| weak var proxyDelegate: UIScrollViewDelegate? | |
| fileprivate(set) weak var scrollView: UIScrollView? | |
| fileprivate(set) weak var originalScrollDelegate: UIScrollViewDelegate? | |
| fileprivate var primaryScrollViewDelegate: UIScrollViewDelegate? { | |
| guard let proxyDelegate = self.proxyDelegate else { | |
| return self.originalScrollDelegate | |
| } | |
| return proxyDelegate | |
| } | |
| // MARK: - Instantiation | |
| init(scrollView: UIScrollView) { | |
| super.init() | |
| self.scrollView = scrollView | |
| self.originalScrollDelegate = scrollView.delegate | |
| scrollView.delegate = self | |
| } | |
| deinit { | |
| printLog("") | |
| self.remove() | |
| } | |
| func remove() { | |
| self.proxyDelegate = nil | |
| self.scrollView?.delegate = self.originalScrollDelegate | |
| } | |
| override func responds(to aSelector: Selector!) -> Bool { | |
| return self.proxyDelegate?.responds(to: aSelector) == true || self.originalScrollDelegate?.responds(to:aSelector) == true || super.responds(to: aSelector) | |
| } | |
| override func forwardingTarget(for aSelector: Selector!) -> Any? { | |
| if let rawObject = self.proxyDelegate, rawObject.responds(to: aSelector) { | |
| return rawObject | |
| } | |
| else if let defualtObject = self.originalScrollDelegate, defualtObject.responds(to: aSelector) { | |
| return self.originalScrollDelegate | |
| } | |
| return super.forwardingTarget(for: aSelector) | |
| } | |
| } | |
| // MARK: - Forwarding Delegates | |
| /// Note: we forward all delegate calls here since Swift does not support forwardInvocation: or NSProxy | |
| extension ScrollViewObserver: UIScrollViewDelegate { | |
| func scrollViewDidScroll(_ scrollView: UIScrollView) { | |
| self.primaryScrollViewDelegate?.scrollViewDidScroll?(scrollView) | |
| } | |
| func scrollViewDidZoom(_ scrollView: UIScrollView) { | |
| self.primaryScrollViewDelegate?.scrollViewDidZoom?(scrollView) | |
| } | |
| func scrollViewWillBeginDragging(_ scrollView: UIScrollView) { | |
| self.primaryScrollViewDelegate?.scrollViewWillBeginDragging?(scrollView) | |
| } | |
| func scrollViewWillEndDragging(_ scrollView: UIScrollView, withVelocity velocity: CGPoint, targetContentOffset: UnsafeMutablePointer<CGPoint>) { | |
| self.primaryScrollViewDelegate?.scrollViewWillEndDragging?(scrollView, withVelocity: velocity, targetContentOffset: targetContentOffset) | |
| } | |
| func scrollViewDidEndDragging(_ scrollView: UIScrollView, willDecelerate decelerate: Bool) { | |
| self.primaryScrollViewDelegate?.scrollViewDidEndDragging?(scrollView, willDecelerate: decelerate) | |
| } | |
| func scrollViewWillBeginDecelerating(_ scrollView: UIScrollView) { | |
| self.primaryScrollViewDelegate?.scrollViewWillBeginDecelerating?(scrollView) | |
| } | |
| func scrollViewDidEndDecelerating(_ scrollView: UIScrollView) { | |
| self.primaryScrollViewDelegate?.scrollViewDidEndDecelerating?(scrollView) | |
| } | |
| func scrollViewDidEndScrollingAnimation(_ scrollView: UIScrollView) { | |
| self.primaryScrollViewDelegate?.scrollViewDidEndScrollingAnimation?(scrollView) | |
| } | |
| func viewForZooming(in scrollView: UIScrollView) -> UIView? { | |
| return self.primaryScrollViewDelegate?.viewForZooming?(in: scrollView) | |
| } | |
| func scrollViewWillBeginZooming(_ scrollView: UIScrollView, with view: UIView?) { | |
| self.primaryScrollViewDelegate?.scrollViewWillBeginZooming?(scrollView, with: view) | |
| } | |
| func scrollViewDidEndZooming(_ scrollView: UIScrollView, with view: UIView?, atScale scale: CGFloat) { | |
| self.primaryScrollViewDelegate?.scrollViewDidEndZooming?(scrollView, with: view, atScale: scale) | |
| } | |
| func scrollViewShouldScrollToTop(_ scrollView: UIScrollView) -> Bool { | |
| return self.primaryScrollViewDelegate?.scrollViewShouldScrollToTop?(scrollView) == true | |
| } | |
| func scrollViewDidScrollToTop(_ scrollView: UIScrollView) { | |
| self.primaryScrollViewDelegate?.scrollViewDidScrollToTop?(scrollView) | |
| } | |
| } |
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