feat: improve scroll delegate

Author: okwasniewski

ios/PagerScrollDelegate.swift

@@ -4,11 +4,21 @@ import UIKit
  Scroll delegate used to control underlying TabView's collection view.
  */
 class PagerScrollDelegate: NSObject, UIScrollViewDelegate, UICollectionViewDelegate {
-  // Store the original delegate to forward calls
   weak var originalDelegate: UICollectionViewDelegate?
   weak var delegate: PagerViewProviderDelegate?
   var orientation: UICollectionView.ScrollDirection = .horizontal
 
+  private let handledSelectors: Set<Selector> = [
+    #selector(scrollViewDidScroll(_:)),
+    #selector(scrollViewWillBeginDragging(_:)),
+    #selector(scrollViewWillBeginDecelerating(_:)),
+    #selector(scrollViewDidEndDecelerating(_:)),
+    #selector(scrollViewDidEndScrollingAnimation(_:)),
+    #selector(scrollViewDidEndDragging(_:willDecelerate:)),
+    #selector(collectionView(_:didEndDisplaying:forItemAt:)),
+    #selector(collectionView(_:willDisplay:forItemAt:))
+  ]
+  
   func scrollViewDidScroll(_ scrollView: UIScrollView) {
     let isHorizontal = orientation == .horizontal
     let pageSize = isHorizontal ? scrollView.frame.width : scrollView.frame.height
@@ -60,39 +70,11 @@ class PagerScrollDelegate: NSObject, UIScrollViewDelegate, UICollectionViewDeleg
   }
 
   override func responds(to aSelector: Selector!) -> Bool {
-    let handledSelectors: [Selector] = [
-      #selector(scrollViewDidScroll(_:)),
-      #selector(scrollViewWillBeginDragging(_:)),
-      #selector(scrollViewWillBeginDecelerating(_:)),
-      #selector(scrollViewDidEndDecelerating(_:)),
-      #selector(scrollViewDidEndScrollingAnimation(_:)),
-      #selector(scrollViewDidEndDragging(_:willDecelerate:)),
-      #selector(collectionView(_:didEndDisplaying:forItemAt:)),
-      #selector(collectionView(_:willDisplay:forItemAt:))
-    ]
-    
-    if handledSelectors.contains(aSelector) {
-      return true
-    }
-    return originalDelegate?.responds(to: aSelector) ?? false
+    handledSelectors.contains(aSelector) || (originalDelegate?.responds(to: aSelector) ?? false)
   }
 
   override func forwardingTarget(for aSelector: Selector!) -> Any? {
-    let handledSelectors: [Selector] = [
-      #selector(scrollViewDidScroll(_:)),
-      #selector(scrollViewWillBeginDragging(_:)),
-      #selector(scrollViewWillBeginDecelerating(_:)),
-      #selector(scrollViewDidEndDecelerating(_:)),
-      #selector(scrollViewDidEndScrollingAnimation(_:)),
-      #selector(scrollViewDidEndDragging(_:willDecelerate:)),
-      #selector(collectionView(_:didEndDisplaying:forItemAt:)),
-      #selector(collectionView(_:willDisplay:forItemAt:))
-    ]
-    
-    if handledSelectors.contains(aSelector) {
-      return nil
-    }
-    return originalDelegate
+    handledSelectors.contains(aSelector) ? nil : originalDelegate
   }
 }
 

ios/PagerViewProvider.swift

@@ -112,7 +112,9 @@ import UIKit
       parentViewController.addChild(hostingController)
       hostingController.view.backgroundColor = .clear
       addSubview(hostingController.view)
-      hostingController.view.frame = bounds
+
+      hostingController.view.translatesAutoresizingMaskIntoConstraints = false
+      hostingController.view.pinEdges(to: self)
 
       hostingController.didMove(toParent: parentViewController)
     }

ios/RNCPagerViewComponentView.mm

@@ -40,7 +40,7 @@ - (instancetype)initWithFrame:(CGRect)frame
     _pagerViewProvider = [[PagerViewProvider alloc] initWithDelegate:self];
     self.contentView = _pagerViewProvider;
   }
-  
+
   return self;
 }
 
@@ -64,34 +64,34 @@ + (BOOL)shouldBeRecycled
 - (void)updateProps:(const facebook::react::Props::Shared &)props oldProps:(const facebook::react::Props::Shared &)oldProps{
   const auto &oldScreenProps = *std::static_pointer_cast<const RNCViewPagerProps>(_props);
   const auto &newScreenProps = *std::static_pointer_cast<const RNCViewPagerProps>(props);
-  
+
   if (_pagerViewProvider.currentPage == -1) {
      _pagerViewProvider.currentPage = newScreenProps.initialPage;
    }
 
   if (oldScreenProps.scrollEnabled != newScreenProps.scrollEnabled) {
      _pagerViewProvider.scrollEnabled = newScreenProps.scrollEnabled;
    }
-  
+
   if (oldScreenProps.overdrag != newScreenProps.overdrag) {
      _pagerViewProvider.overdrag = newScreenProps.overdrag;
    }
-  
+
   if (oldScreenProps.keyboardDismissMode != newScreenProps.keyboardDismissMode) {
     switch (newScreenProps.keyboardDismissMode) {
       case RNCViewPagerKeyboardDismissMode::None:
         _pagerViewProvider.keyboardDismissMode = UIScrollViewKeyboardDismissModeNone;
         break;
-        
+
       case RNCViewPagerKeyboardDismissMode::OnDrag:
         _pagerViewProvider.keyboardDismissMode = UIScrollViewKeyboardDismissModeOnDrag;
     }
    }
-  
+
   if (oldScreenProps.orientation != newScreenProps.orientation) {
     _pagerViewProvider.orientation = newScreenProps.orientation == RNCViewPagerOrientation::Vertical ? UICollectionViewScrollDirectionVertical : UICollectionViewScrollDirectionHorizontal;
   }
-  
+
   if (oldScreenProps.layoutDirection != newScreenProps.layoutDirection) {
     _pagerViewProvider.layoutDirection = newScreenProps.layoutDirection == RNCViewPagerLayoutDirection::Rtl ? PagerLayoutDirectionRtl : PagerLayoutDirectionLtr;
   }
@@ -113,23 +113,23 @@ - (void)onPageSelectedWithPosition:(NSInteger)position {
 
 - (void)onPageScrollStateChangedWithState:(enum PageScrollState)state {
   const auto eventEmitter = [self pagerEventEmitter];
-  
+
   RNCViewPagerEventEmitter::OnPageScrollStateChangedPageScrollState scrollState;
-  
+
   switch (state) {
     case PageScrollStateIdle:
       scrollState = RNCViewPagerEventEmitter::OnPageScrollStateChangedPageScrollState::Idle;
       break;
-      
+
     case PageScrollStateDragging:
       scrollState = RNCViewPagerEventEmitter::OnPageScrollStateChangedPageScrollState::Dragging;
       break;
-      
+
     case PageScrollStateSettling:
       scrollState = RNCViewPagerEventEmitter::OnPageScrollStateChangedPageScrollState::Settling;
       break;
   }
-  
+
   eventEmitter->onPageScrollStateChanged(RNCViewPagerEventEmitter::OnPageScrollStateChanged{
     .pageScrollState = scrollState
   });
@@ -156,14 +156,15 @@ - (void)setPageWithoutAnimation:(NSInteger)index {
 }
 
 - (void)setScrollEnabledImperatively:(BOOL)scrollEnabled {
+  _pagerViewProvider.scrollEnabled = scrollEnabled;
 }
 
 - (std::shared_ptr<const RNCViewPagerEventEmitter>)pagerEventEmitter
 {
   if (!_eventEmitter) {
     return nullptr;
   }
-  
+
   assert(std::dynamic_pointer_cast<const RNCViewPagerEventEmitter>(_eventEmitter));
   return std::static_pointer_cast<const RNCViewPagerEventEmitter>(_eventEmitter);
 }
@@ -174,7 +175,7 @@ - (void)sendScrollEventsForPosition:(NSInteger)position offset:(CGFloat)offset {
     .position = static_cast<double>(position),
     .offset = offset
   });
-  
+
   // This is temporary workaround to allow animations based on onPageScroll event
   // until Fabric implements proper NativeAnimationDriver,
   // see: https://github.com/facebook/react-native/blob/44f431b471c243c92284aa042d3807ba4d04af65/packages/react-native/React/Fabric/Mounting/ComponentViews/ScrollView/RCTScrollViewComponentView.mm#L59