UPDATE: I updated the correction of my definition of Realm, I still get the error.

I'm using Swift and RealmSwift to build my small App and I'm having multiple errors while trying to make it work. The errors I get are mainly from trying to read Objects from the database, since writing them seems to work sometimes. I asked a question previously which was answered with a way to set up the Realm Objects, but now I get this EXC_BAD_ACCESS error. Lets begin with my RealmManager class in which I create the Realm Instance.

我正在使用Swift和RealmSwift来构建我的小型应用程序，在尝试使其工作时出现了多个错误。我遇到的错误主要来自于试图从数据库中读取对象，因为有时编写对象似乎是可行的。我之前问过一个问题，这个问题的答案是设置Realm对象的方法，但现在我得到了EXC_BAD_ACCESS错误。让我们从我的RealmManager类开始，我在其中创建Realm实例。

import RealmSwift
import Foundation

class RealmManager {
  private var configured: Bool

  private var init(){
    self.configured = false
  }

  static let shared = RealmManager()

  lazy var realm: Realm = {
    if !self.configured {
      var config = Realm.Configuration.defaultConfiguration
      let realm = try! Realm(configuration: config)
    } else {
      let realm = try! Realm()
    }
    return realm
  }

  func configure() throws {
    let dbName = "MyApp.realm"
    var dbConf = Realm.Configuration()

    guard let url = dbConf.fileURL?.deletingLastPathComponent().appendingLastPathComponent(dbName) else {
      throw DBError.databaseNameError
    }
    dbConf.fileURL = url
    dbConf.readOnly = false
    dbConf.schemaVersion = 1
    do {
      self.realm = try Realm(configuration: dbConf)
      self.configured = true
    } catch {
      throw DBError.configurationError
    }
  }

Then I call the class from my AppDelegate class:

然后，我从AppDelegate类中调用该类：

class AppDelegate: UIResponder, UIApplicationDelegate, UNUserNotificationCenterDelegate, MessagingDelegate {
  var window: UIWindow
  var realmM: Realm!
  var pushToken: String = ""

  func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions : [UIApplication.LaunchOptionsKey: Any]?)-> Bool {
    self.realmM = openRealm()
    return true
  }

  private func openRealm() -> Realm {
    do {
      try RealmManager.shared.configure()
    } catch {
      print("Didnt configure Realm")
    }
    let realm = RealmManager.shared.realm
    return realm
  }
}

Now this is how I declare 3 of my objects in which I get the EXC_BAD_ACCESS error:

下面是我如何声明我的3个对象，其中我得到EXC_BAD_ACCESS错误：

import Foundation
import RealmSwift

class Carga: Object{
  @Persisted(primaryKey: true) var idCarga : Int32
  @Persisted var idPedido : Int32
  @Persisted var units : Int32
  @Persisted var packages : Int32
  @Persisted var kilograms : Double

  convenience init(_id: Int32, idPedido: Int32, uds: Int32, pkgs: Int32, kgs: Double) {
    self.init()
    self.idCarga = _id
    self.idPedido = idPedido
    self.units = uds
    self.packages = pkgs
    self.kilograms = kgs
  }
}

class Pedido : Object{
  @Persisted(primaryKey: true) var idPedido : Int32
  @Persisted var idLugar : Int32
  @Persisted var cargas = RealmSwift.List<Carga>()  --> Thread 1: EXC_BAD_ACCESS (code=1,adress=0x0)

  convenience init(_id: Int32, idLugar: Int32, listCargas: RealmSwift.List<Carga>) {
    self.init()
    self.idPedido = _id
    self.idLugar = idLugar
    self.cargas = listCargas
  }
}

class Lugar : Object{
  @Persisted(primaryKey: true) var idLugar : Int32
  @Persisted var name : String
  @Persisted var pedidos = RealmSwift.List<Pedido>()  --> Thread 1 :EXC_BAD_ACCESS (code=1,adress=0x0)

  convenience init(_id: Int32, name: String, listPedidos: RealmSwift.List<Pedido>) {
    self.init()
    self.idLugar = _id
    self.name = name
    self.pedidos = listPedidos
  }
}

• IDs are defined as Int32 because the value is read from Firebase Int32 format.


• The error Thread1: EXC_BAD_ACCESS(code=1,address=0x0) is thrown in the following lines:

1- From RealmManager

1-来自RealmManager

self.realm = try Realm(configuration: dbConf)

2- From Realm class

2-来自境界类

Realm.init()

3- RLMObjectSchema PropertiesForClass

3-RLMObjectSchema属性ForClass

getProperties(_:)

4- From the Object initialization

4-从对象初始化

Pedido.init()

Carga.init()

5- From the Object properties

5-从对象属性

@Persisted var cargas = RealmSwift.List()

@Persisted var pedidos = RealmSwift.List()

Do not compile this code block. It is just a representation of the pathing that the Thread1 is following when creating the Realm instance and where the error is happening.

不要编译此代码块。它只是Thread1在创建Realm实例时所遵循的路径以及错误发生的位置的表示。

I believe the error lies in how Realm is configured and the timing of when it's called (AppDelegate?), not the objects themselves.

我认为错误在于Realm的配置方式和调用时间（AppDelegate？），而不是对象本身。

It seems that you're attempting to create a realm var that persists throughout the app and that's generally not best practice. Realm is not thread safe and objects and app function could run on different threads; that would cause the types of errors you're seeing.

你似乎试图创建一个在整个应用程序中持续存在的领域var，这通常不是最佳实践。Realm不是线程安全的，对象和应用程序功能可以在不同的线程上运行；这将导致您所看到的错误类型。

Best practice is to instantiate a Realm object when needed, or per the below example via a singleton pattern. Rule of thumb is it's better to create instances of Realm on demand rather than pre-emptively creating an instance ahead of time and retaining it

最佳实践是在需要时实例化Realm对象，或者按照下面的示例通过单例模式实例化。经验法则是，最好按需创建Realm实例，而不是先发制人地提前创建实例并保留它

When calling Realm(configuration:), Realm itself will internally cache
that object and will return the same object on each subsequent call.
The object remains in the cache until the autoreleasepool it was
created in is drained.
-- from this answer

I will use the code for the three objects (copy and pasted) from the question (see bottom of this answer)

我将使用问题中三个对象的代码（复制并粘贴）（见答案底部）

Then, i'll adopt some code from an answer to a separate question and modify it to write the Realm file to my Mac desktop (iOS functions are similar). You can point the URL to wherever fits your use case. This RealmService is a singleton that should be placed outside of any other classes.

然后，我将采用一个单独问题的答案中的一些代码，并对其进行修改，将Realm文件写入我的Mac桌面（iOS功能类似）。您可以将URL指向适合您的用例的任何位置。这个RealmService是一个单例，应该放在任何其他类之外。

class RealmService {
    private init() {}

    static let shared = RealmService()

    lazy var realm: Realm = {
        //modify below to be your iOS URL/path
        let manager = FileManager()
        let homeURL = manager.homeDirectoryForCurrentUser
        let desktopURL = homeURL.appendingPathComponent("Desktop")
        let pathToThisRealmFile = desktopURL.appendingPathComponent("desktopRealm.realm")
        //modify above to be your iOS URL/path

        var config = Realm.Configuration.defaultConfiguration
        config.fileURL = pathToThisRealmFile
        let realm = try! Realm.init(configuration: config)
        return realm
    }()
}

Note that I am not calling any code from my AppDelegate as there's no reason to. The RealmService only needs to be referenced when you're interacting with Realm. Note this code is for local realm; a Sync'd realm can/should be handled differently.

请注意，我没有从我的AppDelegate调用任何代码，因为没有理由这样做。RealmService只需要在您与Realm交互时被引用。请注意，此代码适用于本地领域；同步领域可以/应该以不同的方式处理。

Then the code to instantiate and write three objects; a Carga, Pedido and Lugar. I added a button to my UI that when clicked, creates the three objects in my desktop Realm.

然后代码实例化并编写三个对象；a Carga、Peido和Lugar。我在我的UI中添加了一个按钮，当点击时，它会在我的桌面Realm中创建三个对象。

func handleButtonClick() {
    let a = Pedido()
    let b = Lugar()
    let c = Carga()

    let realm = RealmService.shared.realm
    try! realm.write {
        realm.add(a)
        realm.add(b)
        realm.add(c)
    }
}

This this code is run and the button is clicked, three files appear on my desktop; desktopRealm.realm, desktopRealm.realm.lock, desktopRealm.realm.management (which is a folder).

这个代码运行后，点击按钮，三个文件出现在我的桌面上；desktopRealm.realm、desktopRealm_realm.lock、desktopRealm.realm.management（这是一个文件夹）。

Upon inspection, the desktopRealm.realm file contains the three objects as expected.

经过检查，desktopRealm.realm文件包含预期的三个对象。

Realm Objects from question

问题中的领域对象

class Carga: Object{
  @Persisted(primaryKey: true) var idCarga : Int32
  @Persisted var idPedido : Int32
  @Persisted var units : Int32
  @Persisted var packages : Int32
  @Persisted var kilograms : Double

  convenience init(_id: Int32, idPedido: Int32, uds: Int32, pkgs: Int32, kgs: Double) {
    self.init()
    self.idCarga = _id
    self.idPedido = idPedido
    self.units = uds
    self.packages = pkgs
    self.kilograms = kgs
  }
}

class Pedido : Object{
  @Persisted(primaryKey: true) var idPedido : Int32
  @Persisted var idLugar : Int32
  @Persisted var cargas = RealmSwift.List<Carga>()

  convenience init(_id: Int32, idLugar: Int32, listCargas: RealmSwift.List<Carga>) {
    self.init()
    self.idPedido = _id
    self.idLugar = idLugar
    self.cargas = listCargas
  }
}

class Lugar : Object{
  @Persisted(primaryKey: true) var idLugar : Int32
  @Persisted var name : String
  @Persisted var pedidos = RealmSwift.List<Pedido>()

  convenience init(_id: Int32, name: String, listPedidos: RealmSwift.List<Pedido>) {
    self.init()
    self.idLugar = _id
    self.name = name
    self.pedidos = listPedidos
  }
}