Changing the indicator API to use the dot syntax, instead of that closure syntax, which is more convenient and swifty

Author: dreampiggy

Example/SDWebImageSwiftUIDemo/ContentView.swift

@@ -96,9 +96,7 @@ struct ContentView: View {
                         } else {
                             #if os(macOS) || os(iOS) || os(tvOS)
                             WebImage(url: URL(string:url))
-                            .indicator { isAnimating, _ in
-                                ActivityIndicator(isAnimating)
-                            }
+                            .indicator(.activity)
                             .resizable()
                             .scaledToFit()
                             .frame(width: CGFloat(100), height: CGFloat(100), alignment: .center)

Example/SDWebImageSwiftUIDemo/DetailView.swift

@@ -57,18 +57,18 @@ struct DetailView: View {
             } else {
                 #if os(macOS) || os(iOS) || os(tvOS)
                 WebImage(url: URL(string:url), options: [.progressiveLoad])
-                .indicator { isAnimating, progress in
-                    ProgressIndicator(isAnimating, progress: progress)
-                }
+                .indicator(.progress)
                 .resizable()
                 .scaledToFit()
                 #else
                 WebImage(url: URL(string:url), options: [.progressiveLoad])
-                .indicator { isAnimating, progress in
-                    ProgressBar(value: progress)
-                    .foregroundColor(.blue)
-                    .frame(maxHeight: 6)
-                }
+                .indicator(
+                    Indicator { isAnimating, progress in
+                        ProgressBar(value: progress)
+                        .foregroundColor(.blue)
+                        .frame(maxHeight: 6)
+                    }
+                )
                 .resizable()
                 .scaledToFit()
                 #endif

Example/SDWebImageSwiftUIDemo/ProgressBar.swift

@@ -16,7 +16,7 @@ public struct ProgressBar: View {
         GeometryReader { geometry in
             ZStack(alignment: .leading) {
                 Rectangle()
-                     .frame(width: geometry.size.width)
+                    .frame(width: geometry.size.width)
                     .opacity(0.3)
                 Rectangle()
                     .frame(width: geometry.size.width * self.value)

README.md

@@ -61,9 +61,9 @@ let package = Package(
 
 ### Using `WebImage` to load network image
 
-- [x] Supports the placeholder and detail options control for image loading as SDWebImage
-- [x] Supports the success/failure/progress changes event for custom handling
-- [x] Supports the indicator with activity/progress indicator and customization
+- [x] Supports placeholder and detail options control for image loading as SDWebImage
+- [x] Supports success/failure/progress changes event for custom handling
+- [x] Supports indicator with activity/progress indicator and customization
 
 Note: This `WebImage` using `Image` for internal implementation, which is the best compatible for SwiftUI layout and animation system. But it supports static image format only, because unlike `UIImageView` in UIKit, SwiftUI's `Image` does not support animation.
 
@@ -73,9 +73,7 @@ var body: some View {
         .onSuccess { image, cacheType in
             // Success
         }
-        .indicator { isAnimating, _ in
-            ActivityIndicator(isAnimating) // Activity Indicator
-        }
+        .indicator(.activity) // Activity Indicator
         .resizable()
         .scaledToFit()
         .frame(width: 300, height: 300, alignment: .center)

SDWebImageSwiftUI/Classes/Indicator/Indicator.swift

@@ -9,16 +9,36 @@
 import Foundation
 import SwiftUI
 
-/// A container view to hold the indicator builder
-public struct Indicator : View {
+/// A  type to build the indicator
+public struct Indicator {
     var builder: (Binding<Bool>, Binding<CGFloat>) -> AnyView
-    public typealias Body = Never
-    public var body: Never {
-        fatalError()
-    }
+    
+    /// Create a indicator with builder
+    /// - Parameter builder: A builder to build indicator
+    /// - Parameter isAnimating: A Binding to control the animation. If image is during loading, the value is true, else (like start loading) the value is false.
+    /// - Parameter progress: A Binding to control the progress during loading. If no progress can be reported, the value is 0.
+    /// Associate a indicator when loading image with url
     public init<T>(@ViewBuilder builder: @escaping (_ isAnimating: Binding<Bool>, _ progress: Binding<CGFloat>) -> T) where T : View {
         self.builder = { isAnimating, progress in
             AnyView(builder(isAnimating, progress))
         }
     }
 }
+
+#if os(macOS) || os(iOS) || os(iOS)
+extension Indicator {
+    /// Activity Indicator
+    public static var activity: Indicator {
+        Indicator { isAnimating, _ in
+            ActivityIndicator(isAnimating)
+        }
+    }
+    
+    /// Progress Indicator
+    public static var progress: Indicator {
+        Indicator { isAnimating, progress in
+            ProgressIndicator(isAnimating, progress: progress)
+        }
+    }
+}
+#endif

SDWebImageSwiftUI/Classes/WebImage.swift

@@ -172,12 +172,10 @@ extension WebImage {
 extension WebImage {
 
     /// Associate a indicator when loading image with url
-    /// - Parameter builder: builder description
-    /// - Parameter isAnimating: A Binding to control the animation. If image is during loading, the value is true, else (like start loading) the value is false.
-    /// - Parameter progress: A Binding to control the progress during loading. If no progress can be reported, the value is 0.
-    public func indicator<T>(_ builder: @escaping (_ isAnimating: Binding<Bool>, _ progress: Binding<CGFloat>) -> T) -> WebImage where T : View {
+    /// - Parameter indicator: The indicator type, see `Indicator`
+    public func indicator(_ indicator: Indicator) -> WebImage {
         var result = self
-        result.indicator = Indicator(builder: builder)
+        result.indicator = indicator
         return result
     }
 }