fix(MultipleSelection): Improve animations

Mail/Components/CheckboxView.swift

@@ -22,6 +22,7 @@ import SwiftUI
 
 struct CheckboxView: View {
     @AppStorage(UserDefaults.shared.key(.accentColor)) private var accentColor = DefaultPreferences.accentColor
+
     let isSelected: Bool
     let size: CGFloat
 
@@ -33,14 +34,15 @@ struct CheckboxView: View {
     var body: some View {
         ZStack {
             Circle()
-                .strokeBorder(Color.accentColor, lineWidth: 2)
+                .strokeBorder(Color.accentColor, lineWidth: isSelected ? 0 : 2)
                 .background(Circle().fill(isSelected ? Color.accentColor : Color.clear))
                 .frame(width: size, height: size)
             MailResourcesAsset.check.swiftUIImage
                 .foregroundColor(accentColor.onAccent.swiftUIColor)
                 .frame(height: UIConstants.checkmarkSize)
                 .opacity(isSelected ? 1 : 0)
         }
+        .animation(nil, value: isSelected)
     }
 }
 

Mail/Components/SelectionBackground.swift

@@ -60,6 +60,7 @@ struct SelectionBackground: View {
 
     let selectionType: SelectionBackgroundKind
     var paddingLeading: CGFloat = 8
+    var withAnimation = true
 
     var body: some View {
         Rectangle()
@@ -68,6 +69,7 @@ struct SelectionBackground: View {
             .padding(.leading, paddingLeading)
             .padding(.vertical, selectionType.verticalPadding)
             .opacity(selectionType.opacity)
+            .animation(withAnimation ? .default : nil, value: selectionType.opacity)
     }
 }
 

Mail/Components/ThreadCell.swift

@@ -21,15 +21,8 @@ import MailResources
 import SwiftUI
 
 extension Animation {
-    static func threadListCheckbox(isMultipleSelectionEnabled isEnabled: Bool) -> Animation {
-        .default.delay(isEnabled ? 0.5 : 0)
-    }
-
-    static func threadListSlide(density: ThreadDensity, isMultipleSelectionEnabled isEnabled: Bool) -> Animation {
-        if density == .large {
-            return .default
-        }
-        return .default.speed(2).delay(isEnabled ? 0 : 0.22)
+    static var threadListSlide: Animation {
+        .default.speed(2)
     }
 }
 
@@ -81,6 +74,10 @@ struct ThreadCellDataHolder {
 
 struct ThreadCell: View {
     @EnvironmentObject private var mailboxManager: MailboxManager
+
+    /// With normal or compact density, the checkbox should appear and disappear at different times of the cell offset.
+    @State private var shouldDisplayCheckbox = false
+
     let thread: Thread
 
     let dataHolder: ThreadCellDataHolder
@@ -104,12 +101,7 @@ struct ThreadCell: View {
         return label
     }
 
-    init(
-        thread: Thread,
-        density: ThreadDensity,
-        isMultipleSelectionEnabled: Bool = false,
-        isSelected: Bool = false
-    ) {
+    init(thread: Thread, density: ThreadDensity, isMultipleSelectionEnabled: Bool = false, isSelected: Bool = false) {
         self.thread = thread
 
         dataHolder = ThreadCellDataHolder(thread: thread)
@@ -124,10 +116,6 @@ struct ThreadCell: View {
     var body: some View {
         HStack(spacing: 8) {
             UnreadIndicatorView(hidden: !thread.hasUnseenMessages)
-                .animation(
-                    .threadListSlide(density: density, isMultipleSelectionEnabled: isMultipleSelectionEnabled),
-                    value: isMultipleSelectionEnabled
-                )
                 .accessibilityLabel(additionalAccessibilityLabel)
                 .accessibilityHidden(additionalAccessibilityLabel.isEmpty)
 
@@ -137,14 +125,13 @@ struct ThreadCell: View {
                         AvatarView(avatarDisplayable: recipient, size: 40)
                         CheckboxView(isSelected: isSelected, density: density)
                             .opacity(isSelected ? 1 : 0)
+                            .animation(nil, value: isSelected)
                     }
                     .accessibility(hidden: true)
                 } else if isMultipleSelectionEnabled {
                     CheckboxView(isSelected: isSelected, density: density)
-                        .animation(
-                            .threadListCheckbox(isMultipleSelectionEnabled: isMultipleSelectionEnabled),
-                            value: isMultipleSelectionEnabled
-                        )
+                        .opacity(shouldDisplayCheckbox ? 1 : 0)
+                        .animation(.default.speed(1.5), value: shouldDisplayCheckbox)
                 }
             }
             .padding(.trailing, 4)
@@ -159,7 +146,7 @@ struct ThreadCell: View {
                 }
             }
             .animation(
-                .threadListSlide(density: density, isMultipleSelectionEnabled: isMultipleSelectionEnabled),
+                isMultipleSelectionEnabled ? .threadListSlide : .threadListSlide.delay(UIConstants.checkboxDisappearOffsetDelay),
                 value: isMultipleSelectionEnabled
             )
         }
@@ -168,6 +155,20 @@ struct ThreadCell: View {
         .padding(.vertical, density.cellVerticalPadding)
         .clipped()
         .accessibilityElement(children: .combine)
+        .onChange(of: isMultipleSelectionEnabled) { isEnabled in
+            guard density != .large else { return }
+
+            withAnimation {
+                if isEnabled {
+                    // We should wait a bit before showing the checkbox
+                    DispatchQueue.main.asyncAfter(deadline: .now() + UIConstants.checkboxAppearDelay) {
+                        self.shouldDisplayCheckbox = true
+                    }
+                } else {
+                    self.shouldDisplayCheckbox = false
+                }
+            }
+        }
     }
 }
 

Mail/Utils/FloatingActionButtonModifier.swift

@@ -42,7 +42,8 @@ struct FloatingActionButtonModifier: ViewModifier {
 }
 
 extension View {
-    func floatingActionButton(isEnabled: Bool = true, icon: MailResourcesImages, title: String, action: @escaping () -> Void) -> some View {
+    func floatingActionButton(isEnabled: Bool = true, icon: MailResourcesImages, title: String,
+                              action: @escaping () -> Void) -> some View {
         modifier(FloatingActionButtonModifier(isEnabled: isEnabled, icon: icon, title: title, action: action))
     }
 }

Mail/Views/Thread List/ThreadListCell.swift

@@ -26,18 +26,18 @@ import SwiftUI
 struct ThreadListCell: View {
     @EnvironmentObject var splitViewManager: SplitViewManager
 
-    let thread: Thread
-
     let viewModel: ThreadListViewModel
-    let multipleSelectionViewModel: ThreadListMultipleSelectionViewModel
+    @ObservedObject var multipleSelectionViewModel: ThreadListMultipleSelectionViewModel
+
+    @Binding var editedMessageDraft: Draft?
+
+    let thread: Thread
 
     let threadDensity: ThreadDensity
 
     let isSelected: Bool
     let isMultiSelected: Bool
 
-    @Binding var editedMessageDraft: Draft?
-
     private var selectionType: SelectionBackgroundKind {
         if multipleSelectionViewModel.isEnabled {
             return isMultiSelected ? .multiple : .none
@@ -52,9 +52,10 @@ struct ThreadListCell: View {
             isMultipleSelectionEnabled: multipleSelectionViewModel.isEnabled,
             isSelected: isMultiSelected
         )
-        .background(SelectionBackground(selectionType: selectionType, paddingLeading: 4))
+        .background(SelectionBackground(selectionType: selectionType, paddingLeading: 4, withAnimation: false))
+        .contentShape(Rectangle())
         .onTapGesture { didTapCell() }
-        .onLongPressGesture(minimumDuration: 0.3) { didLongPressCell() }
+        .onLongPressGesture { didLongPressCell() }
         .swipeActions(thread: thread, viewModel: viewModel, multipleSelectionViewModel: multipleSelectionViewModel)
         .listRowInsets(.init(top: 0, leading: 0, bottom: 0, trailing: 0))
         .listRowSeparator(.hidden)
@@ -100,15 +101,15 @@ struct ThreadListCell: View {
 struct ThreadListCell_Previews: PreviewProvider {
     static var previews: some View {
         ThreadListCell(
-            thread: PreviewHelper.sampleThread,
             viewModel: ThreadListViewModel(mailboxManager: PreviewHelper.sampleMailboxManager,
                                            folder: PreviewHelper.sampleFolder,
                                            isCompact: false),
             multipleSelectionViewModel: ThreadListMultipleSelectionViewModel(mailboxManager: PreviewHelper.sampleMailboxManager),
+            editedMessageDraft: .constant(nil),
+            thread: PreviewHelper.sampleThread,
             threadDensity: .large,
             isSelected: false,
-            isMultiSelected: false,
-            editedMessageDraft: .constant(nil)
+            isMultiSelected: false
         )
     }
 }

Mail/Views/Thread List/ThreadListView.swift

@@ -120,14 +120,14 @@ struct ThreadListView: View {
                     ForEach(viewModel.sections) { section in
                         Section {
                             ForEach(section.threads) { thread in
-                                ThreadListCell(thread: thread,
-                                               viewModel: viewModel,
+                                ThreadListCell(viewModel: viewModel,
                                                multipleSelectionViewModel: multipleSelectionViewModel,
+                                               editedMessageDraft: $editedMessageDraft,
+                                               thread: thread,
                                                threadDensity: threadDensity,
                                                isSelected: viewModel.selectedThread?.uid == thread.uid,
                                                isMultiSelected: multipleSelectionViewModel.selectedItems
-                                                   .contains { $0.id == thread.id },
-                                               editedMessageDraft: $editedMessageDraft)
+                                                   .contains { $0.id == thread.id })
                                     .id(thread.id)
                             }
                         } header: {

MailCore/UI/UIConstants.swift

@@ -91,6 +91,9 @@ public enum UIConstants {
     public static let checkmarkSize: CGFloat = 14
     public static let checkboxLargeSize: CGFloat = 40
 
+    public static let checkboxAppearDelay = 0.2
+    public static let checkboxDisappearOffsetDelay = 0.35
+
     public static let buttonsRadius: CGFloat = 16
     public static let buttonsIconSize: CGFloat = 16