iOS - SwiftData CRUD

SwiftData CRUD

SwiftData를 공부하면서 아직 SwiftUI는 다뤄본 적이 없는데 대부분의 블로그 글들이 SwiftUI로 작성되어있었다. SwiftData가 SwiftUI와 자연스럽게 통합되기 때문인 것 같은데 아직 어떤 부분이 자연스럽게 통합된다는건지 구체적으로 이해가 되지는 않는다!

우선 공부중인 UIKit를 기반으로 SwiftData를 사용해봤다.
이름과 나이를 저장하는 테스트 프로젝트를 만들었다.

---

SwiftData 구현

1. Person Model을 만든다.

import Foundation
import SwiftData

@Model
class Person {
    var name: String
    var age: String
    
    init(name: String, age: String) {
        self.name = name
        self.age = age
    }
    
}

2. MainView와 ListView를 만들어줬다.

class MainView: UIView {
    
    private let nameLabel: UILabel = {
        let label = UILabel()
        label.text = "이름"
        return label
    }()
    
    let nameTextField: UITextField = {
        let tf = UITextField()
        tf.layer.borderWidth = 1.0
        tf.layer.cornerRadius = 10.0
        return tf
    }()
    
    private let ageLabel: UILabel = {
        let label = UILabel()
        label.text = "나이"
        return label
    }()
    
    let ageTextField: UITextField = {
        let tf = UITextField()
        tf.layer.borderWidth = 1.0
        tf.layer.cornerRadius = 10.0
        return tf
    }()
    
    let addButton: UIButton = {
        let btn = UIButton()
        btn.setTitle(" 추가하기 ", for: .normal)
        btn.backgroundColor = .lightGray
        btn.setTitleColor(.black, for: .normal)
        return btn
    }()
    
    let showButton: UIButton = {
        let btn = UIButton()
        btn.setTitle(" 데이터 ", for: .normal)
        btn.backgroundColor = .lightGray
        btn.setTitleColor(.black, for: .normal)
        return btn
    }()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        setUI()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    private func setUI() {
        self.backgroundColor = .systemBackground
        
        addSubview(nameLabel)
        addSubview(nameTextField)
        addSubview(ageLabel)
        addSubview(ageTextField)
        addSubview(addButton)
        addSubview(showButton)
        
        nameLabel.translatesAutoresizingMaskIntoConstraints = false
        nameTextField.translatesAutoresizingMaskIntoConstraints = false
        ageLabel.translatesAutoresizingMaskIntoConstraints = false
        ageTextField.translatesAutoresizingMaskIntoConstraints = false
        addButton.translatesAutoresizingMaskIntoConstraints = false
        showButton.translatesAutoresizingMaskIntoConstraints = false
        
        NSLayoutConstraint.activate([
            nameLabel.topAnchor.constraint(equalTo: topAnchor, constant: 250),
            nameLabel.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 30),
            nameLabel.widthAnchor.constraint(equalToConstant: 40),
            
            nameTextField.centerYAnchor.constraint(equalTo: nameLabel.centerYAnchor),
            nameTextField.leadingAnchor.constraint(equalTo: nameLabel.trailingAnchor, constant: 30),
            nameTextField.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -30),
            nameTextField.heightAnchor.constraint(equalToConstant: 40),
            
            ageLabel.topAnchor.constraint(equalTo: nameLabel.bottomAnchor, constant: 40),
            ageLabel.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 30),
            ageLabel.widthAnchor.constraint(equalToConstant: 40),
            
            ageTextField.centerYAnchor.constraint(equalTo: ageLabel.centerYAnchor),
            ageTextField.leadingAnchor.constraint(equalTo: ageLabel.trailingAnchor, constant: 30),
            ageTextField.trailingAnchor.constraint(equalTo: trailingAnchor, constant: -30),
            ageTextField.heightAnchor.constraint(equalToConstant: 40),
            
            addButton.topAnchor.constraint(equalTo: ageTextField.bottomAnchor, constant: 100),
            addButton.leadingAnchor.constraint(equalTo: leadingAnchor, constant: 120),
            
            showButton.topAnchor.constraint(equalTo: ageTextField.bottomAnchor, constant: 100),
            showButton.leadingAnchor.constraint(equalTo: addButton.trailingAnchor, constant: 10)
        ])
    }
    
}

class ListView: UIView {
    
    let tableView: UITableView = {
        let tv = UITableView()
        tv.backgroundColor = .white
        tv.layer.borderWidth = 1.0
        tv.layer.cornerRadius = 10
        tv.layer.masksToBounds = true
        tv.layer.borderColor = UIColor.black.cgColor
        return tv
    }()
    
    override init(frame: CGRect) {
        super.init(frame: frame)
        setTableView()
    }
    
    required init?(coder: NSCoder) {
        fatalError("init(coder:) has not been implemented")
    }
    
    private func setTableView() {
        self.backgroundColor = .systemBackground
        
        addSubview(tableView)
        
        tableView.translatesAutoresizingMaskIntoConstraints = false
        NSLayoutConstraint.activate([
            tableView.topAnchor.constraint(equalTo: safeAreaLayoutGuide.topAnchor, constant: 10),
            tableView.leadingAnchor.constraint(equalTo: safeAreaLayoutGuide.leadingAnchor, constant: 30),
            tableView.trailingAnchor.constraint(equalTo: safeAreaLayoutGuide.trailingAnchor, constant: -30),
            tableView.bottomAnchor.constraint(equalTo: safeAreaLayoutGuide.bottomAnchor, constant: -10)
        ])
    }
    
}

3. SwiftDataManager 파일을 따로 만들어 로직을 분리해주었다.
   SwiftData를 사용해보는 것이 목표였기 때문에 쉽게 접근할 수 있도록 싱글턴 패턴으로 만들어줬다.

class SwiftDataManager {
    static var shared = SwiftDataManager()
    var container = try? ModelContainer(for: Person.self)
    
    
    // Create
    @MainActor func createPerson(name: String, age: String) {
        let person = Person(name: name, age: age)
        
        do {
            container?.mainContext.insert(person)
            try container?.mainContext.save()
        } catch {
            print("생성 실패: \(error.localizedDescription)")
        }
    }
    
    // Read
    @MainActor func getPerson() -> [Person] {
        // FetchDescriptor를 사용하여 Person 엔터티의 데이터를 가져옴
        let descriptor = FetchDescriptor<Person>()
        
        // container?.mainContext.fetch(descriptor)를 통해 데이터베이스에서 메모를 가져옴
        let persons = (try? container?.mainContext.fetch(descriptor)) ?? []
        return persons
    }
    
    
    // Update
    @MainActor func updatePerson(name: String, age: String, index: Int) {
        let descriptor = FetchDescriptor<Person>()
        
        do {
            guard let result = try container?.mainContext.fetch(descriptor) else {
                return
            }
            
            if index < result.count {
                let personObject = result[index]
                personObject.name = name
                personObject.age = age
                
                try container?.mainContext.save()
            }
        } catch {
            print("수정실패: \(error.localizedDescription)")
        }
    }

    
    // Delete
    @MainActor func deletePerson(person: Person) {
        container?.mainContext.delete(person)
        
        do {
            try container?.mainContext.save()
        } catch {
            print("삭제 실패: \(error.localizedDescription)")
        }
    }

    
}

4. Controller 파일에서 addButton이나 테이블뷰셀 delete시 SwiftDataManager의 로직이 실행된다.

class MainViewController: UIViewController {
    
    private let mainView = MainView()
    
    override func loadView() {
        view = mainView
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        setAddTarget()
    }
    
    private func setAddTarget() {
        mainView.addButton.addTarget(self, action: #selector(addButtonTapped), for: .touchUpInside)
        mainView.showButton.addTarget(self, action: #selector(showButtonTapped), for: .touchUpInside)
    }
    
    @objc private func addButtonTapped() {
        guard let name = mainView.nameTextField.text?.trimmingCharacters(in: .whitespacesAndNewlines),
              !name.isEmpty,
              let age = mainView.ageTextField.text?.trimmingCharacters(in: .whitespacesAndNewlines),
              !age.isEmpty else {
            print("이름이나 나이를 입력하세요")
            return
        }
        SwiftDataManager.shared.createPerson(name: name, age: age)
        setTextField()
    }
    
    @objc private func showButtonTapped() {
        let listVC = ListViewController()
        navigationController?.pushViewController(listVC, animated: true)
    }
    
    private func setTextField() {
        mainView.nameTextField.text = ""
        mainView.ageTextField.text = ""
    }

}

class ListViewController: UIViewController {
    
    private let listView = ListView()
    private var personList: [Person]!
    
    override func loadView() {
        view = listView
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        setTabelView()
        setPersonList()
    }
    
    private func setTabelView() {
        listView.tableView.dataSource = self
        listView.tableView.register(TableViewCell.self, forCellReuseIdentifier: "cell")
    }
    
    private func setPersonList() {
        personList = SwiftDataManager.shared.getPerson()
    }
}


// MARK: - UITableViewDataSource
extension ListViewController: UITableViewDataSource {
    
    func tableView(_ tableView: UITableView, commit editingStyle: UITableViewCell.EditingStyle, forRowAt indexPath: IndexPath) {
        if editingStyle == .delete {
            if let person = personList?[indexPath.row] {
                SwiftDataManager.shared.deletePerson(person: person)
                setPersonList()
            }
            tableView.deleteRows(at: [indexPath], with: .fade)
        }
    }
    
    func tableView(_ tableView: UITableView, numberOfRowsInSection section: Int) -> Int {
        return personList.count
    }
    
    func tableView(_ tableView: UITableView, cellForRowAt indexPath: IndexPath) -> UITableViewCell {
        guard let cell = tableView.dequeueReusableCell(withIdentifier: "cell", for: indexPath) as? TableViewCell else {
            return UITableViewCell()
        }
        
        cell.nameLabel.text = personList[indexPath.row].name
        cell.ageLabel.text = personList[indexPath.row].age
        
        cell.editButtonClosure = { [weak self] in
            guard let self = self else { return }
            self.showAlert(index: indexPath.row)
        }
        
        return cell
    }
    
    private func showAlert(index: Int) {
        let alertController = UIAlertController(title: "데이터 수정", message: nil, preferredStyle: .alert)
        
        alertController.addTextField { textField in
            textField.placeholder = "이름"
        }
        
        alertController.addTextField { textField in
            textField.placeholder = "나이"
        }
        
        let cancelAction = UIAlertAction(title: "취소", style: .cancel, handler: nil)
        
        let saveAction = UIAlertAction(title: "확인", style: .default) { _ in
            guard let newName = alertController.textFields?[0].text,
                  let newAge = alertController.textFields?[1].text,
                  !newName.trimmingCharacters(in: .whitespaces).isEmpty,
                  !newAge.trimmingCharacters(in: .whitespaces).isEmpty else {
                alertController.textFields?[0].placeholder = "이름을 입력해 주세요."
                alertController.textFields?[1].placeholder = "나이를 입력해 주세요."
                return
            }
            
            SwiftDataManager.shared.updatePerson(name: newName, age: newAge, index: index)
            self.listView.tableView.reloadData()
        }
        
        alertController.addAction(cancelAction)
        alertController.addAction(saveAction)
        self.present(alertController, animated: true, completion: nil)
    }
    
}

---

CoreData와 SwiftData

CoreData와 SwiftData의 차이점

프레임워크 vs 라이브러리
CoreData: 애플이 제공하는 프레임워크
SwiftData: 오픈소스 라이브러리

데이터 모델 정의 방식
CoreData: Core Data 모델 편집기에서 사용하는 .xcdatamodeld 파일을 사용한다.
SwiftData: Swift 클래스를 사용하고 @Model 어트리뷰트를 사용하여 데이터 모델을 선언한다.

CoreData와 SwiftData의 공통점

CoreData와 SwiftData 모두 데이터베이스 관리를 위한 라이브러리라는 공통점이 있다. 또한 CoreData와 SwiftData 두개 다 SQL 쿼리를 직접 작성하지 않고도 데이터베이스 작업을 수행할 수 있고, local storage에 데이터가 저장되어 앱을 종료했다 재실행해도 데이터가 남아있지만 앱을 삭제하면 데이터가 삭제된다.

현재는 SwiftData를 iOS 17 이전 버전에서 사용이 불가능해서 앱에서 낮은 iOS 버전을 지원하려면 Core Data를 사용해야한다!!