👌 Simplify usage of scroll view delegate during recovery

appcues · Dec 6, 2023 · c9b32d0 · c9b32d0
1 parent dfcb17c
commit c9b32d0
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Showing 2 changed files with 18 additions and 12 deletions.
diff --git a/Sources/AppcuesKit/Presentation/ExperienceRendering/ExperienceRenderer.swift b/Sources/AppcuesKit/Presentation/ExperienceRendering/ExperienceRenderer.swift
@@ -61,7 +61,7 @@ internal class StepRecoveryObserver: ExperienceStateObserver {
     }
 
     func stopRetryHandler() {
-        AppcuesScrollViewDelegate.shared.observer = nil
+        AppcuesScrollViewDelegate.shared.detach()
     }
 
     func evaluateIfSatisfied(result: ExperienceStateObserver.StateResult) -> Bool {
@@ -74,7 +74,7 @@ internal class StepRecoveryObserver: ExperienceStateObserver {
     }
 
     private func startRetryHandler() {
-        AppcuesScrollViewDelegate.shared.observer = self
+        AppcuesScrollViewDelegate.shared.attach(using: self)
     }
 }
 
@@ -106,9 +106,6 @@ internal class ExperienceRenderer: ExperienceRendering, StateMachineOwning {
         self.stepRecoveryObserver = StepRecoveryObserver(stateMachine: stateMachine)
 
         stateMachines[ownerFor: .modal] = self
-
-        // TODO: guard against multiple
-        UIScrollView.swizzleScrollViewGetDelegate()
     }
 
     func start(owner: StateMachineOwning, forContext context: RenderContext) {
@@ -170,9 +167,7 @@ internal class ExperienceRenderer: ExperienceRendering, StateMachineOwning {
 
     private func show(experience: ExperienceData, completion: ((Result<Void, Error>) -> Void)?) {
         guard Thread.isMainThread else {
-            DispatchQueue.main.async {
-                self.show(experience: experience, completion: completion)
-            }
+            DispatchQueue.main.async { self.show(experience: experience, completion: completion) }
             return
         }
 
@@ -376,9 +371,7 @@ internal class ExperienceRenderer: ExperienceRendering, StateMachineOwning {
 
     func resetAll() {
         guard Thread.isMainThread else {
-            DispatchQueue.main.async {
-                self.resetAll()
-            }
+            DispatchQueue.main.async { self.resetAll() }
             return
         }
 

diff --git a/Sources/AppcuesKit/Presentation/Extensions/UIScrollView+ScrollObserver.swift b/Sources/AppcuesKit/Presentation/Extensions/UIScrollView+ScrollObserver.swift
@@ -23,7 +23,20 @@ internal class AppcuesScrollViewDelegate: NSObject, UIScrollViewDelegate {
     // This could have been a more sophisticated list of weak references to some Protocol implementation,
     // but that would seem to add unnecessary complexity and list management, when really only a single
     // RenderContext in the application (the modal context) can be in recovery mode at any given time.
-    weak var observer: StepRecoveryObserver?
+    private weak var observer: StepRecoveryObserver?
+
+    override private init() {
+        super.init()
+        UIScrollView.swizzleScrollViewGetDelegate()
+    }
+
+    func attach(using observer: StepRecoveryObserver) {
+        self.observer = observer
+    }
+
+    func detach() {
+        self.observer = nil
+    }
 
     // if any scroll activity is currently active, cancel any pending scrollEnded notifications
     // and wait for the next scroll completion to attempt any retry