Reverting data changes using the undo manager
Automatically record data change operations that people perform in your SwiftUI app, and let them undo and redo those changes.
Overview
People who interact with apps to change data typically expect the app to provide a way to revert changes that they no longer wish to make. To provide this undo support, apps can use UndoManager, which can:
Record operations that a person performs while using the app
Provide undo capability to revert the last operation
Provide redo capability to reapply the last reverted operation
If your app uses SwiftData, it can automatically register data changes with the undo manager. No need for you to add more code to your app that records those changes. Instead, just enable undo in SwiftData.
Enable undo in SwiftData
Using SwiftData to store data, you can enable undo support for data changes by setting the isUndoEnabled parameter to true when applying the modelContainer(for:inMemory:isAutosaveEnabled:isUndoEnabled:onSetup:) modifier to a scene or view in your SwiftUI app:
@main
struct SwiftDataAnimalsApp: App {
var body: some Scene {
WindowGroup() {
ContentView()
}
.modelContainer(for: AnimalCategory.self, isUndoEnabled: true)
}
}By default, the isUndoEnabled parameter value is false, which disables undo support in SwiftData. If you set this parameter to true in your app, the app’s window or window group provides the system’s undo manager to SwiftData. SwiftData then binds the undo manager to the mainContext of the ModelContainer. When someone makes data changes in your app and the app saves those changes to the main context, they can use system gestures in iOS and iPadOS like three finger swap and device shake, or choose Edit > Undo or Edit > Redo in macOS, to undo and redo those changes, respectively.
Other than enabling undo in SwiftData, you don’t need to write any additional code to manage undo operations for data changes. Instead, SwiftData automatically registers data change operations with the undo manager each time SwiftData saves those changes to the main context. And if your app uses DocumentGroup to manage data storage, undo and redo in SwiftData is automatically enabled.