Multi select improvements

ViewModel/LibraryViewModel.swift

@@ -44,8 +44,27 @@ enum LibraryState {
 }
 
 final class LibraryViewModel: ObservableObject {
-    @Published var selectedZimFile: ZimFile?
-    @Published var multiSelectedZimFiles = Set<ZimFile>()
+    @Published var selectedZimFile: ZimFile? {
+        didSet {
+            if let selectedZimFile {
+                multiSelectedZimFiles = Set([selectedZimFile])
+            } else {
+                multiSelectedZimFiles.removeAll()
+            }
+        }
+    }
+    @Published var multiSelectedZimFiles = Set<ZimFile>() {
+        didSet {
+            switch multiSelectedZimFiles.count {
+            case 0 where selectedZimFile != nil:
+                selectedZimFile = nil
+            case 1 where selectedZimFile == nil:
+                selectedZimFile = multiSelectedZimFiles.first
+            default:
+                break
+            }
+        }
+    }
     @MainActor @Published private(set) var error: Error?
     /// Note: due to multiple instances of LibraryViewModel,
     /// this `state` should not be changed directly, modify the `process.state` instead

Views/Library/Library.swift

@@ -149,9 +149,6 @@ struct LibraryZimFileContext<Content: View>: View {
                 content
                     .gesture(TapGesture().modifiers(.command).onEnded({ value in
                         viewModel.toggleMultiSelect(of: zimFile)
-                        if viewModel.multiSelectedZimFiles.count > 0 {
-                            viewModel.selectedZimFile = nil
-                        }
                     }))
                     .gesture(TapGesture().onEnded({ _ in
                         viewModel.selectedZimFile = zimFile

Views/Library/ZimFilesOpened.swift

@@ -63,10 +63,6 @@ struct ZimFilesOpened: View {
         }
         .onChange(of: zimFiles.count) { _ in
             viewModel.selectedZimFile = zimFiles.first // makes sure we also nil out, if all ZIMs were unlinked
-            viewModel.multiSelectedZimFiles.removeAll()
-        }
-        .onDisappear {
-            viewModel.multiSelectedZimFiles.removeAll()
         }
         // not using OpenFileButton here, because it does not work on iOS/iPadOS 15 when this view is in a modal
         .fileImporter(