Animate chevron rotation

iOS/AppAssets.swift

@@ -48,12 +48,12 @@ struct AppAssets {
 		return UIImage(systemName: "circle")!
 	}()
 	
-	static var chevronDownImage: UIImage = {
+	static var chevronSmallImage: UIImage = {
-		return UIImage(systemName: "chevron.down")!
+		return UIImage(named: "chevronSmall")!
 	}()
 	
-	static var chevronRightImage: UIImage = {
+	static var chevronBaseImage: UIImage = {
-		return UIImage(systemName: "chevron.right")!
+		return UIImage(named: "chevronBase")!
 	}()
 	
 	static var copyImage: UIImage = {

iOS/MasterFeed/Cell/MasterFeedTableViewCell.swift

@@ -152,15 +152,18 @@ private extension MasterFeedTableViewCell {
 	func addDisclosureView() {
 		disclosureButton = NonIntrinsicButton(type: .roundedRect)
 		disclosureButton!.addTarget(self, action: #selector(buttonPressed(_:)), for: UIControl.Event.touchUpInside)
+		disclosureButton?.setImage(AppAssets.chevronBaseImage, for: .normal)
 		updateDisclosureImage()
 		addSubviewAtInit(disclosureButton!)
 	}
 	
 	func updateDisclosureImage() {
-		if disclosureExpanded {
+		UIView.animate(withDuration: 0.3) {
-			disclosureButton?.setImage(AppAssets.chevronDownImage, for: .normal)
+			if self.disclosureExpanded {
-		} else {
+				self.disclosureButton?.imageView?.transform = CGAffineTransform(rotationAngle: 1.570796)
-			disclosureButton?.setImage(AppAssets.chevronRightImage, for: .normal)
+			} else {
+				self.disclosureButton?.imageView?.transform = CGAffineTransform(rotationAngle: 0)
+			}
 		}
 	}
 

iOS/MasterFeed/Cell/MasterFeedTableViewSectionHeader.swift

@@ -66,6 +66,8 @@ class MasterFeedTableViewSectionHeader: UITableViewHeaderFooterView {
 	private let unreadCountView = MasterFeedUnreadCountView(frame: CGRect.zero)
 	private var disclosureView: UIImageView = {
 		let iView = NonIntrinsicImageView()
+		iView.tintColor = UIColor.tertiaryLabel
+		iView.image = AppAssets.chevronSmallImage
 		iView.contentMode = .center
 		return iView
 	}()
@@ -131,11 +133,12 @@ private extension MasterFeedTableViewSectionHeader {
 	}
 	
 	func updateDisclosureImage() {
-		disclosureView.tintColor = UIColor.tertiaryLabel
+		UIView.animate(withDuration: 0.3) {
-		if disclosureExpanded {
+			if self.disclosureExpanded {
-			disclosureView.image = AppAssets.chevronDownImage
+				self.disclosureView.transform = CGAffineTransform(rotationAngle: 1.570796)
-		} else {
+			} else {
-			disclosureView.image = AppAssets.chevronRightImage
+				self.disclosureView.transform = CGAffineTransform(rotationAngle: 0)
+			}
 		}
 	}
 

iOS/Resources/Assets.xcassets/chevronBase.imageset/Contents.json

@@ -0,0 +1,15 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "filename" : "chevron-base.pdf"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  },
+  "properties" : {
+    "template-rendering-intent" : "template"
+  }
+}

iOS/Resources/Assets.xcassets/chevronSmall.imageset/Contents.json

@@ -0,0 +1,15 @@
+{
+  "images" : [
+    {
+      "idiom" : "universal",
+      "filename" : "chevron-small.pdf"
+    }
+  ],
+  "info" : {
+    "version" : 1,
+    "author" : "xcode"
+  },
+  "properties" : {
+    "template-rendering-intent" : "template"
+  }
+}