In iOS 17, Apple launched a brand new framework known as SwiftData to exchange the Core Knowledge framework. Earlier, we have now written an introductory tutorial about SwiftData and confirmed you the best way to pair SwiftData with SwiftUI.
Whereas there are quite a few studying sources obtainable for utilizing SwiftData with SwiftUI, some readers have talked about that discovering complete guides for integrating SwiftData into UIKit apps may be difficult. On this tutorial, we’ll delve into the method of leveraging the capabilities of SwiftData inside the UIKit framework.
A Fast Introduction about SwiftData
To start out off, let’s take a short tour of the SwiftData framework. It’s vital to grasp that SwiftData shouldn’t be mistaken for a database itself. As an alternative, it’s a framework constructed upon Core Knowledge, particularly developed to help builders in successfully managing and interacting with information saved persistently. Whereas the default persistent retailer utilized by iOS is usually the SQLite database, it’s price noting that persistent shops can are available varied kinds. As an illustration, Core Knowledge may also be employed to handle information saved in an area file, reminiscent of an XML file. This flexibility permits builders to decide on probably the most appropriate persistent retailer for his or her particular necessities.
Whether or not you go for Core Knowledge or the SwiftData framework, each instruments goal to simplify the intricacies of the underlying persistent retailer for builders. Take the SQLite database, for instance. With SwiftData, there’s no must concern your self with establishing database connections or delving into SQL queries to retrieve information data. As an alternative, builders can concentrate on using user-friendly APIs and Swift Macros, reminiscent of @Mannequin, to effectively handle information inside their functions. This abstraction permits for a extra streamlined and intuitive information administration expertise.
When you have used Core Knowledge earlier than, you might keep in mind that it’s a must to create a knowledge mannequin (with a file extension .xcdatamodeld) utilizing a knowledge mannequin editor for information persistence. With the discharge of SwiftData, you not want to try this. SwiftData streamlines the entire course of with macros, one other new Swift function in iOS 17. Say, for instance, you already outline a mannequin class for Track as follows:
|
class Track { var title: String var artist: String var album: String var style: String var score: Double } |
To make use of SwiftData, the brand new @Mannequin macro is the important thing for storing persistent information utilizing SwiftUI. As an alternative of constructing the info mannequin with mannequin editor, SwiftData simply requires you to annotate the mannequin class with the @Mannequin macro like this:
|
@Mannequin class Track { var title: String var artist: String var album: String var style: String var score: Double } |
That is the way you outline the schema of the info mannequin in code. With this straightforward key phrase, SwiftData mechanically allows persistence for the info class and affords different information administration functionalities reminiscent of iCloud sync. Attributes are inferred from properties and it helps fundamental worth sorts reminiscent of Int and String.
SwiftData means that you can customise how your schema is constructed utilizing property metadata. You’ll be able to add uniqueness constraints through the use of the @Attribute annotation, and delete propagation guidelines with the @Relationship annotation. If there are specific properties you do not need included, you should utilize the @Transient macro to inform SwiftData to exclude them. Right here is an instance:
|
@Mannequin class Album { @Attribute(.distinctive) var identify: String var artist: String var style: String
// The cascade relationship instructs SwiftData to delete all // songs when the album is deleted. @Attribute(.cascade) var songs: [Song]? = [] } |
To drive the info persistent operations, there are two key objects of SwiftData that you have to be conversant in: ModelContainer and ModelContext. The ModelContainer serves because the persistent backend on your mannequin sorts. To create a ModelContainer, you merely must instantiate an occasion of it.
|
// Fundamental let container = attempt ModelContainer(for: [Song.self, Album.self])
// With configuration let container = attempt ModelContainer(for: [Song.self, Album.self], configurations: ModelConfiguration(url: URL(“path”)))) |
In UIKit, you may instantiate the context for a given mannequin containers like this:
|
let context = ModelContext(modelContainer) |
With the context, you might be able to fetch information. You need to use the brand new #Predicate macro to construct predicates. Right here is an instance:
|
// Specify all of the songs whose style is “Pop” let songPredicate = #Predicate<Track> { $0.style == “pop” } |
When you outline the factors for fetching, you should utilize the FetchDescriptor and inform the mannequin context to fetch the info.
|
let descriptor = FetchDescriptor<Track>(predicate: songPredicate)
let songs = attempt context.fetch(descriptor) |
To insert merchandise within the persistent retailer, you may name the insert technique of the mannequin context and move it the mannequin objects to insert.
|
modelContext.insert(track) |
Equally, you may delete the merchandise through the mannequin context like this:
|
modelContext.delete(track) |
This serves as a short introduction to SwiftData. Should you’re nonetheless feeling uncertain about the best way to make the most of SwiftData, there’s no want to fret. You’ll achieve a transparent understanding of its utilization as we’ll construct a easy To-do app utilizing UIKit and SwiftData.
Constructing a Easy To-do App with SwiftData and UIKit
I’ve already developed a fundamental to-do app utilizing UIKit. Nevertheless, the present implementation solely shops the to-do gadgets in reminiscence, which implies the info just isn’t persistent. With a view to deal with this limitation, our subsequent step is to change the app and change from utilizing in-memory arrays to leveraging the facility of SwiftData for storing the to-do gadgets in a database. This enhancement will be sure that the to-do gadgets are saved persistently, permitting customers to entry them even after closing the app.
For demo function, the present model of this app doesn’t present the performance for customers so as to add their very own to-do gadgets. As an alternative, customers can solely add a random to-do merchandise by tapping the “+” button. Nevertheless, customers can nonetheless modify the standing of the prevailing merchandise and delete it by swiping.
Utilizing @Mannequin for the mannequin class
The in-memory model of the app already defines a struct for ToDoItem:
|
struct ToDoItem: Identifiable, Hashable { var id: UUID var identify: String var isComplete: Bool
init(id: UUID = UUID(), identify: String = “”, isComplete: Bool = false) { self.id = id self.identify = identify self.isComplete = isComplete } } |
To make use of SwiftData, we are able to convert this struct to class and annotate it with the @Mannequin macro like this:
|
import SwiftData
@Mannequin class ToDoItem: Identifiable, Hashable { var id: UUID var identify: String var isComplete: Bool
init(id: UUID = UUID(), identify: String = “”, isComplete: Bool = false) { self.id = id self.identify = identify self.isComplete = isComplete } } |
As you may see, the one factor that we have to do to make a category work with SwiftData is to prefix it with @Mannequin. SwiftData then mechanically allows persistence for the info class.
Saving To-Do Gadgets into Database
Within the demo app, we have now the ToDoTableViewController class to deal with the rendering of the to-do desk view, in addition to, the random creation of the to-do gadgets. To handle information with SwiftData, we first create a variable to carry the mannequin container:
|
var container: ModelContainer? |
Within the viewDidLoad technique, we are able to add the next line of code to instantiate the mannequin container:
|
container = attempt? ModelContainer(for: ToDoItem.self) |
For including a random to-do merchandise, the demo app already had a way named addToDoItem:
|
@IBAction func addToDoItem(sender: UIBarButtonItem) { todoItems.append(generateRandomTodoItem()) updateSnapshot(animatingChange: true) } |
We known as up the generateRandomTodoItem technique to get a to-do merchandise and append it to the todoItems array. Then we name up the updateSnapshot technique to replace the desk view.
With a view to save the to-do merchandise completely, we are able to substitute the code like this:
|
@IBAction func addToDoItem(sender: UIBarButtonItem) { container?.mainContext.insert(generateRandomTodoItem()) fetchToDoItems() } |
As an alternative of merely including the to-do merchandise to the array, we make the most of the insert technique of the container’s context to avoid wasting the merchandise into the interior database.
Fetching Knowledge from Database
The implementation of the fetchToDoItems technique is pending for the time being. To retrieve information from the database, we have to create an occasion of FetchDescriptor. This enables us to specify the info sort we wish to retrieve and outline any particular search standards if mandatory. By using the FetchDescriptor, we are able to successfully retrieve the specified information from the database. After establishing the fetch descriptor object, we are able to proceed to name the fetch technique of the container’s context and supply the descriptor as an argument. SwiftData will then make the most of this data to retrieve the to-do gadgets accordingly from the database.
Insert the next code snippet to create the fetchToDoItems technique:
|
func fetchToDoItems() { let descriptor = FetchDescriptor<ToDoItem>()
todoItems = (attempt? container?.mainContext.fetch(descriptor)) ?? []
updateSnapshot() } |
As soon as we retrieve all of the to-do gadgets, we have to invoke the updateSnapshot technique to replace the desk view.
Deleting Knowledge from Database
Within the pattern app, we have now a swipe motion for deleting a row merchandise like this:
|
let deleteAction = UIContextualAction(model: .harmful, title: “Delete”) { (motion, sourceView, completionHandler) in
var snapshot = self.dataSource.snapshot() snapshot.deleteItems([todoItem]) self.dataSource.apply(snapshot, animatingDifferences: true)
// Name completion handler to dismiss the motion button completionHandler(true) } |
For now, it solely removes a to-do merchandise from the desk view however not the database. To utterly delete the merchandise from database, we have to insert a line of code within the closure:
|
self.container?.mainContext.delete(todoItem) |
By calling the delete technique and offering the related merchandise, SwiftData will handle eradicating the desired merchandise from the database, guaranteeing that it’s not continued in our app’s information storage.
That is how we migrate the to-do app from utilizing in-memory storage to database utilizing SwiftData.
Abstract
By following the steps outlined above, we efficiently migrated the to-do app from utilizing in-memory storage to using a database with the assistance of SwiftData. As demonstrated, the mix of the @Mannequin macro and SwiftData framework simplifies the method of incorporating a database into an app.
We hope that via this tutorial, you now possess a clearer understanding of the best way to combine SwiftData right into a SwiftUI venture and carry out important CRUD (Create, Learn, Replace, Delete) operations. Apple has invested important effort in making persistent information administration and information modeling extra accessible for Swift builders, together with newcomers to the language.
With SwiftData, you may have a strong instrument at your disposal to deal with information storage and retrieval effectively. We encourage you to discover additional and leverage the capabilities of SwiftData to boost your app improvement journey.