NEW: My new book Pro SwiftUI is out now – level up your SwiftUI skills today! >>

Deleting from a Core Data fetch request

Paul Hudson    @twostraws   

We already used @FetchRequest to place Core Data objects into a SwiftUI List, and with only a little more work we can enable both swipe to delete and a dedicated Edit/Done button.

Just as with regular arrays of data, most of the work is done by attaching an onDelete(perform:) modifier to ForEach, but rather than just removing items from an array we instead need to find the requested object in our fetch request then use it to call delete() on our managed object context. Once all the objects are deleted we can trigger another save of the context; without that the changes won’t actually be written out to disk.

So, start by adding this method to ContentView:

func deleteBooks(at offsets: IndexSet) {
    for offset in offsets {
        // find this book in our fetch request
        let book = books[offset]

        // delete it from the context

    // save the context

We can trigger that by adding an onDelete(perform:) modifier to the ForEach of ContentView, but remember: it needs to go on the ForEach and not the List.

Add this modifier now:

.onDelete(perform: deleteBooks)

That gets us swipe to delete, and we can go one better by adding an Edit/Done button too. Find the toolbar() modifier in ContentView, and add another ToolbarItem:

ToolbarItem(placement: .navigationBarLeading) {

That completes ContentView, so try running the app – you should be able to add and delete books freely now, and can delete by using swipe to delete or using the edit button.

Hacking with Swift is sponsored by Stream

SPONSORED Build a functional Twitter clone using APIs and SwiftUI with Stream's 7-part tutorial series. In just four days, learn how to create your own Twitter using Stream Chat, Algolia, 100ms, Mux, and RevenueCat.

Try now!

Sponsor Hacking with Swift and reach the world's largest Swift community!

Buy Pro Swift Buy Pro SwiftUI Buy Swift Design Patterns Buy Testing Swift Buy Hacking with iOS Buy Swift Coding Challenges Buy Swift on Sundays Volume One Buy Server-Side Swift Buy Advanced iOS Volume One Buy Advanced iOS Volume Two Buy Advanced iOS Volume Three Buy Hacking with watchOS Buy Hacking with tvOS Buy Hacking with macOS Buy Dive Into SpriteKit Buy Swift in Sixty Seconds Buy Objective-C for Swift Developers Buy Beyond Code

Was this page useful? Let us know!

Average rating: 4.8/5

Unknown user

You are not logged in

Log in or create account

Link copied to your pasteboard.