Move onSelect/onDeselect to an async callback to give UICollectionVie…

…w time to schedule animations. Add more signpost logging.
square · Jun 3, 2020 · dd97264 · dd97264
1 parent 26ac904
commit dd97264
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Showing 9 changed files with 106 additions and 17 deletions.
diff --git a/Demo/Sources/Demos/Demo Screens/ScrollViewEdgesPlaygroundViewController.swift b/Demo/Sources/Demos/Demo Screens/ScrollViewEdgesPlaygroundViewController.swift
@@ -7,7 +7,7 @@
 //
 
 import UIKit
-@testable import Listable
+import Listable
 
 
 final class ScrollViewEdgesPlaygroundViewController : UIViewController, UIScrollViewDelegate

diff --git a/Demo/Sources/Demos/DemosRootViewController.swift b/Demo/Sources/Demos/DemosRootViewController.swift
@@ -143,6 +143,14 @@ public final class DemosRootViewController : UIViewController
                     DemoItem(text: "Tappable Row"),
                     selectionStyle: .tappable
                 )
+
+                section += Item(
+                    DemoItem(text: "Tappable Row (Slow Is Selected)"),
+                    selectionStyle: .tappable,
+                    onSelect: { _ in
+                        Thread.sleep(forTimeInterval: 0.5)
+                    }
+                )
             }
 
             list += Section(identifier: "collection-view") { section in

diff --git a/Listable/Sources/Debugging and Logging/SignpostLogger.swift b/Listable/Sources/Debugging and Logging/SignpostLogger.swift
@@ -19,6 +19,11 @@ extension OSLog {
         subsystem: "com.kve.Listable",
         category: "ListView ScrollView"
     )
+
+    static let listInteraction = OSLog(
+        subsystem: "com.kve.Listable",
+        category: "ListView Interaction"
+    )
 }
 
 

diff --git a/Listable/Sources/Identifier.swift b/Listable/Sources/Identifier.swift
@@ -8,7 +8,7 @@
 import Foundation
 
 
-public final class AnyIdentifier : Hashable
+public final class AnyIdentifier : Hashable, CustomDebugStringConvertible
 {
     private let value : AnyHashable
 
@@ -36,13 +36,19 @@ public final class AnyIdentifier : Hashable
     {
         hasher.combine(self.hash)
     }
+
+    // MARK: CustomDebugStringConvertible
+
+    public var debugDescription: String {
+        self.value.identifierContentString
+    }
 }
 
 
-public final class Identifier<Represented> : Hashable
+public final class Identifier<Represented> : Hashable, CustomDebugStringConvertible
 {
     private let type : ObjectIdentifier
-    private let value : AnyHashable?
+    private let value : AnyHashable
 
     private let hash : Int
 
@@ -82,4 +88,24 @@ public final class Identifier<Represented> : Hashable
     {
         hasher.combine(self.hash)
     }
+
+    // MARK: CustomDebugStringConvertible
+
+    public var debugDescription: String {
+        "Identifier<\(String(describing: Represented.self))>: \(self.value.identifierContentString)"
+    }
+}
+
+
+fileprivate extension AnyHashable
+{
+    var identifierContentString : String {
+        if let base = self.base as? CustomDebugStringConvertible {
+            return base.debugDescription
+        } else if let base = self.base as? CustomStringConvertible {
+            return base.description
+        } else {
+            return self.debugDescription
+        }
+    }
 }
diff --git a/Listable/Sources/Internal/Presentation State/PresentationState.ItemState.swift b/Listable/Sources/Internal/Presentation State/PresentationState.ItemState.swift
@@ -277,10 +277,27 @@ extension PresentationState
         {
             self.storage.state.isSelected = isSelected
 
-            if isSelected {
-                self.model.onSelect?(self.model.content)
-            } else {
-                self.model.onDeselect?(self.model.content)
+            /// Schedule the caller-provided callbacks to happen after one runloop. Why?
+            ///
+            /// Because this method is called from within `UICollectionViewDelegate` callbacks,
+            /// This delay gives the `UICollectionView` time to schedule any necessary animations
+            /// for changes to the highlight and selection state – otherwise, these animations get
+            /// stuck behind the call to the `onSelect` or `onDeselect` blocks, which creates the appearance
+            /// of a laggy UI if these callbacks are slow.
+            DispatchQueue.main.async {
+                if isSelected {
+                    if let onSelect = self.model.onSelect {
+                        SignpostLogger.log(log: .listInteraction, name: "Item onSelect", for: self.model) {
+                            onSelect(self.model.content)
+                        }
+                    }
+                } else {
+                    if let onDeselect = self.model.onDeselect {
+                        SignpostLogger.log(log: .listInteraction, name: "Item onDeselect", for: self.model) {
+                            onDeselect(self.model.content)
+                        }
+                    }
+                }
             }
         }
 

diff --git a/Listable/Sources/Item/Item.swift b/Listable/Sources/Item/Item.swift
@@ -210,7 +210,7 @@ extension Item : SignpostLoggable
     var signpostInfo : SignpostLoggingInfo {
         SignpostLoggingInfo(
             identifier: self.debuggingIdentifier,
-            instanceIdentifier: nil
+            instanceIdentifier: self.identifier.debugDescription
         )
     }
 }

diff --git a/Listable/Sources/ListScrollPositionInfo.swift b/Listable/Sources/ListScrollPositionInfo.swift
@@ -89,7 +89,7 @@ public struct ListScrollPositionInfo : Equatable {
     private let scrollViewState : ScrollViewState
 
     /// Creates a `ListScrollPositionInfo` for the provided scroll view.
-    init(
+    public init(
         scrollView : UIScrollView,
         visibleItems : Set<AnyIdentifier>,
         isFirstItemVisible : Bool,

diff --git a/Listable/Tests/IdentifierTests.swift b/Listable/Tests/IdentifierTests.swift
@@ -6,8 +6,41 @@
 //
 
 import XCTest
+import Listable
 
-class IdentifierTests: XCTestCase
+
+class AnyIdentifierTests: XCTestCase
 {
+    func test_debugDescription()
+    {
+        XCTAssertEqual(
+            Identifier<TestingType>("The Value").toAny.debugDescription,
+            "Identifier<TestingType>: \"The Value\""
+        )
+
+        XCTAssertEqual(
+            Identifier<TestingType>(123).toAny.debugDescription,
+            "Identifier<TestingType>: 123"
+        )
+    }
+}
+
 
+class IdentifierTests: XCTestCase
+{
+    func test_debugDescription()
+    {
+        XCTAssertEqual(
+            Identifier<TestingType>("The Value").debugDescription,
+            "Identifier<TestingType>: \"The Value\""
+        )
+
+        XCTAssertEqual(
+            Identifier<TestingType>(123).debugDescription,
+            "Identifier<TestingType>: 123"
+        )
+    }
 }
+
+
+fileprivate struct TestingType { }
diff --git a/Podfile.lock b/Podfile.lock
@@ -1,16 +1,16 @@
 PODS:
-  - BlueprintLists (0.1.1):
+  - BlueprintLists (0.6.0):
     - BlueprintUI
     - Listable
-  - BlueprintLists/Tests (0.1.1):
+  - BlueprintLists/Tests (0.6.0):
     - BlueprintUI
     - Listable
   - BlueprintUI (0.11.0)
   - BlueprintUICommonControls (0.11.0):
     - BlueprintUI
   - EnglishDictionary (1.0.0.LOCAL)
-  - Listable (1.0.0.LOCAL)
-  - Listable/Tests (1.0.0.LOCAL):
+  - Listable (0.6.0)
+  - Listable/Tests (0.6.0):
     - EnglishDictionary
     - Snapshot
   - Snapshot (1.0.0.LOCAL)
@@ -43,11 +43,11 @@ EXTERNAL SOURCES:
     :path: Internal Pods/Snapshot/Snapshot.podspec
 
 SPEC CHECKSUMS:
-  BlueprintLists: 519830595f2d2109299b599e46729cd22a0128ea
+  BlueprintLists: 7dde9b8cf1139be5aa5e84fb05f01a56df498c12
   BlueprintUI: bc5bc9913d897c10dc44c544747afc2a63b26744
   BlueprintUICommonControls: d982c07e38112d9d2d5f5d315c0edc54db0d349e
   EnglishDictionary: f03968b9382ddc5c8dd63535efbf783c6cd45f1c
-  Listable: c4273b65906a0624b9aefce781743095ab8971f9
+  Listable: 836bc4b9756a96aa47e29a2e59e57386666a3288
   Snapshot: cda3414db426919d09f775434b36289c8e864183
 
 PODFILE CHECKSUM: ede5b0b1b0dfe04b49195609ea6bccb6b577e01f