Fix memory leaks on component disposal for iOS and Android

Co-authored-by: troZee <[email protected]>

Author: Copilot

android/src/main/java/com/reactnativepagerview/NestedScrollableHost.kt

@@ -25,6 +25,7 @@ class NestedScrollableHost : FrameLayout {
   constructor(context: Context, attrs: AttributeSet?) : super(context, attrs)
   public var initialIndex: Int? = null
   public var didSetInitialIndex = false
+  public var pageChangeCallback: ViewPager2.OnPageChangeCallback? = null
   private var touchSlop = 0
   private var initialX = 0f
   private var initialY = 0f

android/src/main/java/com/reactnativepagerview/PagerViewViewManager.kt

@@ -52,7 +52,7 @@ class PagerViewViewManager : ViewGroupManager<NestedScrollableHost>(), RNCViewPa
         vp.isSaveEnabled = false
 
         vp.post {
-            vp.registerOnPageChangeCallback(object : OnPageChangeCallback() {
+            val callback = object : OnPageChangeCallback() {
                 override fun onPageScrolled(position: Int, positionOffset: Float, positionOffsetPixels: Int) {
                     super.onPageScrolled(position, positionOffset, positionOffsetPixels)
                     UIManagerHelper.getEventDispatcherForReactTag(reactContext, host.id)?.dispatchEvent(
@@ -79,7 +79,9 @@ class PagerViewViewManager : ViewGroupManager<NestedScrollableHost>(), RNCViewPa
                             PageScrollStateChangedEvent(host.id, pageScrollState)
                     )
                 }
-            })
+            }
+            host.pageChangeCallback = callback
+            vp.registerOnPageChangeCallback(callback)
             UIManagerHelper.getEventDispatcherForReactTag(reactContext, host.id)?.dispatchEvent(
                     PageSelectedEvent(host.id, vp.currentItem)
             )
@@ -200,6 +202,20 @@ class PagerViewViewManager : ViewGroupManager<NestedScrollableHost>(), RNCViewPa
         }
     }
 
+    override fun onDropViewInstance(view: NestedScrollableHost) {
+        // Unregister the page change callback to prevent memory leaks
+        val viewPager = PagerViewViewManagerImpl.getViewPager(view)
+        view.pageChangeCallback?.let { callback ->
+            viewPager.unregisterOnPageChangeCallback(callback)
+            view.pageChangeCallback = null
+        }
+        
+        // Clear the adapter to release references to child views
+        viewPager.adapter = null
+        
+        super.onDropViewInstance(view)
+    }
+
     override fun getExportedCustomDirectEventTypeConstants(): MutableMap<String, Map<String, String>> {
         return MapBuilder.of(
                 PageScrollEvent.EVENT_NAME, MapBuilder.of("registrationName", "onPageScroll"),

android/src/main/java/com/reactnativepagerview/ViewPagerAdapter.kt

@@ -30,6 +30,12 @@ class ViewPagerAdapter() : Adapter<ViewPagerViewHolder>() {
     container.addView(child)
   }
 
+  override fun onViewRecycled(holder: ViewPagerViewHolder) {
+    super.onViewRecycled(holder)
+    // Clean up the holder's container to prevent memory leaks
+    holder.container.removeAllViews()
+  }
+
   override fun getItemCount(): Int {
     return childrenViews.size
   }

ios/RNCPagerViewComponentView.mm

@@ -81,10 +81,32 @@ - (instancetype)initWithFrame:(CGRect)frame
     return self;
 }
 
+- (void)dealloc {
+    // Clean up delegates to prevent memory leaks
+    if (_nativePageViewController) {
+        _nativePageViewController.dataSource = nil;
+        _nativePageViewController.delegate = nil;
+    }
+    
+    if (scrollView) {
+        scrollView.delegate = nil;
+    }
+}
+
 - (void)willMoveToSuperview:(UIView *)newSuperview {
     if (newSuperview != nil) {
         [self initializeNativePageViewController];
         [self goTo:_currentIndex animated:NO];
+    } else {
+        // Component is being removed from view hierarchy, clean up delegates
+        if (_nativePageViewController) {
+            _nativePageViewController.dataSource = nil;
+            _nativePageViewController.delegate = nil;
+        }
+        
+        if (scrollView) {
+            scrollView.delegate = nil;
+        }
     }
 }
 
@@ -124,6 +146,21 @@ -(void)updateLayoutMetrics:(const facebook::react::LayoutMetrics &)layoutMetrics
 
 -(void)prepareForRecycle {
     [super prepareForRecycle];
+    
+    // Clear delegates to prevent memory leaks
+    if (_nativePageViewController) {
+        _nativePageViewController.dataSource = nil;
+        _nativePageViewController.delegate = nil;
+    }
+    
+    if (scrollView) {
+        scrollView.delegate = nil;
+        scrollView = nil;
+    }
+    
+    // Clear view controllers array
+    [_nativeChildrenViewControllers removeAllObjects];
+    
     _nativePageViewController = nil;
     _currentIndex = -1;
 }