Using Core Data With SwiftUI - An Introduction

How does Apple intend for us to use Core Data with SwiftUI?

They gave us a path forward with the most recent beta release of iOS 13 (Beta 5 at the time of this writing)!

First Things First

  • To work effectively with Core Data in SwiftUI, the Data Flow Through SwiftUI WWDC session is a huge help.

  • With this talk under your belt, you’ll have at least been introduced to key words like @State, @Binding, @ObservableObject (which replaces @BindableObject as of Beta 5), and @Environment.

On the Right Path

Even prior to Beta 5, the “right path” for using Core Data with SwiftUI seemed to be through the @Environment.

In the release notes for iOS Beta 5, Apple seems to be leading us there:

  • NSManagedObject now conforms to ObservableObject.

  • The new @FetchRequest property wrapper can drive views from the results of a fetch request

  • managedObjectContext is now included in the environment.

With these three pieces in place, Apple has given us out-of-the-box support for using Core Data with SwiftUI.

So…

How Do You Get Started?

I decided to create a basic, single-view app that can

  • Persist a list of BlogIdeas to a Core Data persistent store
  • Use the new @FetchRequest property wrapper to fetch BlogIdeas
  • Use the @Environment’s managedObjectContext to create, update, and delete BlogIdeas

Grab the project over at GitHub and explore!

The sample project that includes a single Core Data Entity named BlogIdea:

Blog Idea Entity

I kept as much out-of-the-box stuff as I could.

How Does It Work?

Throughout the project, you’ll notice emoji symbols to help draw your eye to the Core Data pieces.

❇️ Alerts you to Core Data pieces

ℹ️ Alerts you to general info about what my brain was thinking when I wrote the code

Code Walkthroughs

I completely relate if you need to chunk things up and inspect the details of how each piece of the puzzle looks in isolation before you dive into the full app.

I’ve written up two separate how-tos that show you more specific details:

How to Pass NSManagedObjectContext to a SwiftUI View

Breaks down how to pass an NSManagedObjectContext instance to your SwiftUI Views.

How to Use @FetchRequest in SwiftUI

Breaks down how to use the @FetchRequest property wrapper in your SwiftUI Views.

comments powered by Disqus