Added offset publisher. See README on how to use it.

README.md

@@ -52,44 +52,53 @@ ScrollView { proxy in
 Everything put together in an example
 
 ```swift
-struct ScrollViewProxySimpleExample: View {
+struct ScrollViewProxyExample: View {
     
     @State var randomInt = Int.random(in: 0..<200)
     @State var proxy: ScrollViewProxy? = nil
+    @State var offset: CGPoint = .zero
     
     var body: some View {
-        VStack {
-            ScrollView { proxy in
-                ForEach(0..<200) { index in
-                    VStack {
-                        Text("\(index)").font(.title)
-                        Spacer()
+        // GeometryReader for safeAreaInsets on Sticky View
+        GeometryReader { geometry in 
+            VStack {
+                ScrollView { proxy in
+                    Text("Sticky View")
+                        .background(Color.white)
+                        .onReceive(proxy.offset) { self.offset = $0 }
+                        .offset(x: offset.x, y: offset.y + geometry.safeAreaInsets.top)
+                        .zIndex(1)
+                    
+                    VStack(spacing: 20) {
+                        ForEach(0..<200) { index in
+                            HStack {
+                                Spacer()
+                                Text("Item: \(index)").font(.title)
+                                Spacer()
+                            }.scrollId(index)
+                        }
+                    }
+                    .zIndex(0)
+                    .onAppear {
+                        self.proxy = proxy
                     }
-                    .padding()
-                    .scrollId(index)
-                }.onAppear {
-                    self.proxy = proxy
                 }
-            }
-            HStack {
-                Button(action: {
-                    self.proxy?.scrollTo(self.randomInt, alignment: .center)
-                    self.randomInt = Int.random(in: 0..<200)
-                }, label: {
-                    Text("Go to \(self.randomInt)")
-                })
-                Spacer()
-                Button(action: { self.proxy?.scrollTo(.top) }, label: {
-                    Text("Top")
-                })
-                Spacer()
-                Button(action: { self.proxy?.scrollTo(.center) }, label: {
-                    Text("Center")
-                })
-                Spacer()
-                Button(action: { self.proxy?.scrollTo(.bottom) }, label: {
-                    Text("Bottom")
-                })
+                HStack {
+                    Button(action: {
+                        self.proxy?.scrollTo(self.randomInt, alignment: .center)
+                        self.randomInt = Int.random(in: 0..<200)
+                    }, label: {
+                        Text("Go to \(self.randomInt)")
+                    })
+                    Spacer()
+                    Button(action: { self.proxy?.scrollTo(.bottom) }, label: {
+                        Text("Bottom")
+                    })
+                    Spacer()
+                    Button(action: { self.proxy?.scrollTo(.center) }, label: {
+                        Text("Center")
+                    })
+                }.padding()
             }
         }
     }

Sources/ScrollViewProxy/ScrollViewProxy.swift

@@ -2,12 +2,25 @@
 // https://twitter.com/amzdme
 import Introspect
 import SwiftUI
+import Combine
+
+// MARK: Fix for name collision when using SwiftUI 2.0
+
+@available(iOS 13.0, OSX 10.15, tvOS 13.0, watchOS 6.0, *)
+public typealias AmzdScrollViewProxy = ScrollViewProxy
+@available(iOS 13.0, OSX 10.15, tvOS 13.0, watchOS 6.0, *)
+public typealias AmzdScrollViewReader = ScrollViewReader
+
+// MARK: Platform specifics
 
 #if os(macOS)
 public typealias PlatformScrollView = NSScrollView
+
 var visibleSizePath = \PlatformScrollView.documentVisibleRect.size
 var adjustedContentInsetPath = \PlatformScrollView.contentInsets
 var contentSizePath = \PlatformScrollView.documentView!.frame.size
+
+@available(iOS 13.0, OSX 10.15, tvOS 13.0, watchOS 6.0, *)
 extension NSScrollView {
     func scrollRectToVisible(_ rect: CGRect, animated: Bool) {
         if animated {
@@ -19,15 +32,50 @@ extension NSScrollView {
             contentView.scrollToVisible(rect)
         }
     }
+    var offsetPublisher: OffsetPublisher {
+        publisher(for: \.contentView.bounds.origin).eraseToAnyPublisher()
+    }
+}
+
+extension NSEdgeInsets {
+    /// top + bottom
+    var vertical: CGFloat {
+        return top + bottom
+    }
+    /// left + right
+    var horizontal: CGFloat {
+        return left + right
+    }
 }
 #elseif os(iOS) || os(tvOS)
 public typealias PlatformScrollView = UIScrollView
-@available(iOS 12.0, *)
+
+@available(iOS 13.0, OSX 10.15, tvOS 13.0, watchOS 6.0, *)
 var visibleSizePath = \PlatformScrollView.visibleSize
 var adjustedContentInsetPath = \PlatformScrollView.adjustedContentInset
 var contentSizePath = \PlatformScrollView.contentSize
+
+@available(iOS 13.0, OSX 10.15, tvOS 13.0, watchOS 6.0, *)
+extension UIScrollView {
+    var offsetPublisher: OffsetPublisher {
+        publisher(for: \.contentOffset).eraseToAnyPublisher()
+    }
+}
+
+extension UIEdgeInsets {
+    /// top + bottom
+    var vertical: CGFloat {
+        return top + bottom
+    }
+    /// left + right
+    var horizontal: CGFloat {
+        return left + right
+    }
+}
 #endif
 
+// MARK: Helper extensions
+
 @available(iOS 13.0, OSX 10.15, tvOS 13.0, watchOS 6.0, *)
 extension ScrollView {
     /// Creates a ScrollView with a ScrollViewReader
@@ -49,6 +97,8 @@ extension View {
     public func id<ID: Hashable>(_ id: ID, scrollView: ScrollViewProxy) -> some View { self }
 }
 
+// MARK: Preferences
+
 @available(iOS 13.0, OSX 10.15, tvOS 13.0, watchOS 6.0, *)
 struct ScrollViewProxyPreferenceData: Equatable {
     static func == (lhs: Self, rhs: Self) -> Bool {
@@ -80,6 +130,8 @@ struct ScrollViewProxyPreferenceModifier: ViewModifier {
     }
 }
 
+// MARK: ScrollViewReader
+
 @available(iOS 13.0, OSX 10.15, tvOS 13.0, watchOS 6.0, *)
 public struct ScrollViewReader<Content: View>: View {
     private var content: (ScrollViewProxy) -> Content
@@ -102,10 +154,18 @@ public struct ScrollViewReader<Content: View>: View {
                 // seems this will not be called due to ScrollView/Preference issues
                 // https://stackoverflow.com/a/61765994/3019595
             }
-            .introspectScrollView { self.proxy.coordinator.scrollView = $0 }
+            .introspectScrollView {
+                self.proxy.coordinator.scrollView = $0
+                self.proxy.offset = $0.offsetPublisher
+            }
     }
 }
 
+// MARK: ScrollViewProxy
+
+@available(iOS 13.0, OSX 10.15, tvOS 13.0, watchOS 6.0, *)
+public typealias OffsetPublisher = AnyPublisher<CGPoint, Never>
+
 @available(iOS 13.0, OSX 10.15, tvOS 13.0, watchOS 6.0, *)
 public struct ScrollViewProxy {
     fileprivate class Coordinator {
@@ -116,6 +176,8 @@ public struct ScrollViewProxy {
     fileprivate var space: UUID = UUID()
 
     fileprivate init() {}
+    
+    public var offset: OffsetPublisher = Just(.zero).eraseToAnyPublisher()
 
     /// Scrolls to an edge or corner
     public func scrollTo(_ alignment: Alignment, animated: Bool = true) {
@@ -187,27 +249,3 @@ public struct ScrollViewProxy {
     }
 }
 
-#if os(macOS)
-extension NSEdgeInsets {
-    /// top + bottom
-    var vertical: CGFloat {
-        return top + bottom
-    }
-    /// left + right
-    var horizontal: CGFloat {
-        return left + right
-    }
-}
-#elseif os(iOS) || os(tvOS)
-extension UIEdgeInsets {
-    /// top + bottom
-    var vertical: CGFloat {
-        return top + bottom
-    }
-    /// left + right
-    var horizontal: CGFloat {
-        return left + right
-    }
-}
-#endif
-