Update the logic to be compatible with LazyVStack's resetting status behavior

Author: dreampiggy

SDWebImageSwiftUI/Classes/AnimatedImage.swift

@@ -44,7 +44,7 @@ final class AnimatedLoadingModel : ObservableObject, IndicatorReportable {
     @Published var isLoading: Bool = false // whether network is loading or cache is querying, should only be used for indicator binding
     @Published var progress: Double = 0 // network progress, should only be used for indicator binding
 
-    /// Used for  loading status recording to avoid recursive `updateView`. There are 3 types of loading (Name/Data/URL)
+    /// Used for loading status recording to avoid recursive `updateView`. There are 3 types of loading (Name/Data/URL)
     @Published var imageName: String?
     @Published var imageData: Data?
     @Published var imageURL: URL?
@@ -206,12 +206,27 @@ public struct AnimatedImage : PlatformViewRepresentable {
     }
     #endif
 
-    func loadImage(_ view: AnimatedImageViewWrapper, context: Context) {
-        let operationKey = NSStringFromClass(type(of: view.wrapped))
-        let currentOperation = view.wrapped.sd_imageLoadOperation(forKey: operationKey)
-        if currentOperation != nil {
-            return
+    func setupIndicator(_ view: AnimatedImageViewWrapper, context: Context) {
+        view.wrapped.sd_imageIndicator = imageConfiguration.indicator
+        view.wrapped.sd_imageTransition = imageConfiguration.transition
+        if let placeholderView = imageConfiguration.placeholderView {
+            placeholderView.removeFromSuperview()
+            placeholderView.isHidden = true
+            // Placeholder View should below the Indicator View
+            if let indicatorView = imageConfiguration.indicator?.indicatorView {
+                #if os(macOS)
+                view.wrapped.addSubview(placeholderView, positioned: .below, relativeTo: indicatorView)
+                #else
+                view.wrapped.insertSubview(placeholderView, belowSubview: indicatorView)
+                #endif
+            } else {
+                view.wrapped.addSubview(placeholderView)
+            }
+            placeholderView.bindFrameToSuperviewBounds()
         }
+    }
+    
+    func loadImage(_ view: AnimatedImageViewWrapper, context: Context) {
         self.imageLoading.isLoading = true
         let options = imageModel.webOptions
         if options.contains(.delayPlaceholder) {
@@ -234,9 +249,9 @@ public struct AnimatedImage : PlatformViewRepresentable {
             self.imageHandler.progressBlock?(receivedSize, expectedSize)
         }) { (image, data, error, cacheType, finished, _) in
             if #available(iOS 14.0, macOS 11.0, watchOS 7.0, tvOS 14.0, *) {
-                // Do nothing
+                // Do nothing. on iOS 14's SwiftUI, the @Published will always trigger another `updateUIView` call with new UIView instance.
             } else {
-                // This is a hack because of Xcode 11.3 bug, the @Published does not trigger another `updateUIView` call
+                // This is a hack because of iOS 13's SwiftUI bug, the @Published does not trigger another `updateUIView` call
                 // Here I have to use UIKit/AppKit API to triger the same effect (the window change implicitly cause re-render)
                 if let hostingView = AnimatedImage.findHostingView(from: view) {
                     if let _ = hostingView.window {
@@ -284,26 +299,28 @@ public struct AnimatedImage : PlatformViewRepresentable {
             let image = SDAnimatedImage(data: data, scale: imageModel.scale)
             imageLoading.imageData = data
             view.wrapped.image = image
-        } else if let url = imageModel.url, url != imageLoading.imageURL {
-            imageLoading.imageURL = url
-            view.wrapped.sd_imageIndicator = imageConfiguration.indicator
-            view.wrapped.sd_imageTransition = imageConfiguration.transition
-            if let placeholderView = imageConfiguration.placeholderView {
-                placeholderView.removeFromSuperview()
-                placeholderView.isHidden = true
-                // Placeholder View should below the Indicator View
-                if let indicatorView = imageConfiguration.indicator?.indicatorView {
-                    #if os(macOS)
-                    view.wrapped.addSubview(placeholderView, positioned: .below, relativeTo: indicatorView)
-                    #else
-                    view.wrapped.insertSubview(placeholderView, belowSubview: indicatorView)
-                    #endif
+        } else if let url = imageModel.url {
+            // Determine if image already been loaded and URL is match
+            var shouldLoad: Bool
+            if url != imageLoading.imageURL {
+                // Change the URL, need new loading
+                shouldLoad = true
+                imageLoading.imageURL = url
+            } else {
+                // Same URL, check if already loaded
+                if imageLoading.isLoading {
+                    shouldLoad = false
+                } else if let image = imageLoading.image {
+                    shouldLoad = false
+                    view.wrapped.image = image
                 } else {
-                    view.wrapped.addSubview(placeholderView)
+                    shouldLoad = true
                 }
-                placeholderView.bindFrameToSuperviewBounds()
             }
-            loadImage(view, context: context)
+            if shouldLoad {
+                setupIndicator(view, context: context)
+                loadImage(view, context: context)
+            }
         }
 
         #if os(macOS)