Essential Apple Frameworks for Beginner Developers

Alex Huang

May 17

Estimated reading time: 8 minute(s)

SwiftUI

Overview

Key Features

Practical Example

import SwiftUI

struct ContentView: View {
    var body: some View {
        Text("Hello, World!")
    }
}

UIKit

Overview

Key Features

Practical Example

import UIKit

class ViewController: UIViewController {
    override func viewDidLoad() {
        super.viewDidLoad()

        let button = UIButton(type: .system)
        button.setTitle("Tap me!", for: .normal)
        button.frame = CGRect(x: 100, y: 100, width: 100, height: 50)
        view.addSubview(button)
    }
}

Core Data

Overview

Key Features

Practical Example

import CoreData

// Define a new entity and save it
let entity = NSEntityDescription.entity(forEntityName: "Person", in: context)
let newPerson = NSManagedObject(entity: entity!, insertInto: context)
newPerson.setValue("John", forKey: "name")

do {
    try context.save()
} catch {
    print("Failed saving")
}

// Fetch the saved data
let request = NSFetchRequest<NSFetchRequestResult>(entityName: "Person")
do {
    let result = try context.fetch(request)
    for data in result as! [NSManagedObject] {
        print(data.value(forKey: "name") as! String)
    }
} catch {
    print("Failed fetching")
}

Combine

Overview

Key Features

Practical Example

import Combine

let publisher = Just("Hello, Combine!")
let subscriber = Subscribers.Sink<String, Never>(
    receiveCompletion: { completion in
        print("Received completion: \(completion)")
    },
    receiveValue: { value in
        print("Received value: \(value)")
    }
)
publisher.subscribe(subscriber)

ARKit

Overview

Key Features

Practical Example

import ARKit
import SceneKit
import UIKit

class ViewController: UIViewController, ARSCNViewDelegate {
    var sceneView: ARSCNView!

    override func viewDidLoad() {
        super.viewDidLoad()

        sceneView = ARSCNView(frame: self.view.frame)
        self.view.addSubview(sceneView)
        sceneView.delegate = self

        let scene = SCNScene()
        sceneView.scene = scene

        let box = SCNBox(width: 0.1, height: 0.1, length: 0.1, chamferRadius: 0.01)
        let boxNode = SCNNode(geometry: box)
        boxNode.position = SCNVector3(0, 0, -0.5)
        scene.rootNode.addChildNode(boxNode)
    }

    override func viewWillAppear(_ animated: Bool) {
        super.viewWillAppear(animated)

        let configuration = ARWorldTrackingConfiguration()
        sceneView.session.run(configuration)
    }

    override func viewWillDisappear(_ animated: Bool) {
        super.viewWillDisappear(animated)

        sceneView.session.pause()
    }
}

HealthKit

Overview

Key Features

Practical Example

import HealthKit

let healthStore = HKHealthStore()

if HKHealthStore.isHealthDataAvailable() {
    let stepCountType = HKQuantityType.quantityType(forIdentifier: .stepCount)!
    let readDataTypes = Set([stepCountType])

    healthStore.requestAuthorization(toShare: nil, read: readDataTypes) { success, error in
        if success {
            let query = HKSampleQuery(sampleType: stepCountType, predicate: nil, limit: 0, sortDescriptors: nil) { query, results, error in
                guard let results = results as? [HKQuantitySample] else {
                    return
                }
                for result in results {
                    print("Steps: \(result.quantity)")
                }
            }
            healthStore.execute(query)
        }
    }
}

CloudKit

Overview

Key Features

Practical Example

import CloudKit

let container = CKContainer.default()
let publicDatabase = container.publicCloudDatabase

// Save a record
let record = CKRecord(recordType: "Note")
record["content"] = "Hello, CloudKit!"
publicDatabase.save(record) { record, error in
    if let error = error {
        print("Error saving record: \(error)")
    } else {
        print("Record saved successfully")
    }
}

// Fetch records
let query = CKQuery(recordType: "Note", predicate: NSPredicate(value: true))
publicDatabase.perform(query, inZoneWith: nil) { records, error in
    if let error = error {
        print("Error fetching records: \(error)")
    } else {
        if let records = records {
            for record in records {
                print("Fetched record: \(record["content"])")
            }
        }
    }
}

WidgetKit

Overview

Key Features

Practical Example

import WidgetKit
import SwiftUI

struct SimpleEntry: TimelineEntry {
    let date: Date
}

struct SimpleWidgetEntryView: View {
    var entry: SimpleEntry

    var body: some View {
        Text(entry.date, style: .time)
    }
}

@main
struct SimpleWidget: Widget {
    let kind: String = "SimpleWidget"

    var body: some WidgetConfiguration {
        StaticConfiguration(kind: kind, provider: SimpleProvider()) { entry in
            SimpleWidgetEntryView(entry: entry)
        }
        .configurationDisplayName("Simple Widget")
        .description("This is an example widget.")
    }
}

struct SimpleProvider: TimelineProvider {
    func placeholder(in context: Context) -> SimpleEntry {
        SimpleEntry(date: Date())
    }

    func getSnapshot(in context: Context, completion: @escaping (SimpleEntry) -> ()) {
        let entry = SimpleEntry(date: Date())
        completion(entry)
    }

    func getTimeline(in context: Context, completion: @escaping (Timeline<SimpleEntry>) -> ()) {
        var entries: [SimpleEntry] = []
        let currentDate = Date()
        for hourOffset in 0 ..< 5 {
            let entryDate = Calendar.current.date(byAdding: .hour, value: hourOffset, to: currentDate)!
            let entry = SimpleEntry(date: entryDate)
            entries.append(entry)
        }
        let timeline = Timeline(entries: entries, policy: .atEnd)
        completion(timeline)
    }
}

Conclusion