Inicio Rápido con sincronizar - Java SDK

Los SDK de dispositivos Atlas están obsoletos. Consulte deprecation page for details.

Tip

Esta guía utiliza la sincronización de dispositivos

Esta guía le ayuda a comenzar a usar una aplicación de Android que se comunica con un backend de aplicación. La aplicación ofrece funciones como Sincronización, funciones de dominio y gestión de usuarios. Si su aplicación solo requiere la funcionalidad de base de datos local, consulte la guía de inicio rápido (solo local).

Esta página contiene información para integrar rápidamente Atlas App Services en tu aplicación. Antes de empezar, asegúrate de que:

Inicializar reino

Before you can use Realm in your app, you must initialize the Realm library. Your application should initialize Realm just once each time the application runs.

Para inicializar la biblioteca Realm, proporcione un Android context A la Realm.init() función estática. Puede proporcionar una Actividad, Fragmento o Aplicación context para la inicialización sin ninguna diferencia de comportamiento. Puede inicializar la biblioteca Realm en el onCreate() método de una subclase de aplicación. para garantizar que solo inicialice Realm una vez cada vez que se ejecute la aplicación.

Realm.init(this); // context, usually an Activity or Application

Realm.init(this) // context, usually an Activity or Application

Tip

Register Your Application Subclass in the Android Manifest

If you create your own Application subclass, you must add it to your application's AndroidManifest.xml to execute your custom application logic. Set the android.name property of your manifest's application definition to ensure that Android instantiates your Application subclass before any other class when a user launches your application.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
   package="com.mongodb.example">
   <application
      android:name=".MyApplicationSubclass"
      ...
   />
</manifest>

Inicializar la aplicación

To use App Services features such as authentication and sync, access your App Services App using your App ID. You can find your App ID in the App Services UI.

app = new App(new AppConfiguration.Builder(appID)
    .build());

val appID : String = YOUR_APP_ID;
app = App(AppConfiguration.Builder(appID)
        .build())

Nota

¿Errores de Android Studio?

Si Android Studio no reconoce los tipos Realm, App o AppConfiguration, podría haber un problema con la configuración de compilación de Gradle. Para solucionar el problema:

Clean your project with Build > Clean Project
Reconstruya su proyecto basándose en su archivo build.gradle actualizado con Build > Rebuild Project
Vuelva a visitar la guía Instale el Java SDK para asegurarse de haber instalado correctamente las dependencias.

Define tu modelo de objeto

El modelo de datos de tu aplicación define la estructura de los datos almacenados dentro de Realm y sincronizados desde y hacia App Services. Se puede definir el modelo de datos de la aplicación de dos formas:

Via schemas in App Services.
A través de clases de Kotlin o Java en código de aplicación con modelos de objetos Realm.

Este inicio rápido utiliza el segundo enfoque, que define tu esquema utilizando clases en el código de tu aplicación móvil. Para definir el modelo de objeto de tu aplicación de esta manera, tienes que habilitar el Modo de desarrollo.

Once you've enabled Development Mode, add the following class definitions to your application code:

import io.realm.RealmObject;
import io.realm.annotations.PrimaryKey;
import io.realm.annotations.RealmClass;
import io.realm.annotations.Required;
import org.bson.types.ObjectId;
public class Task extends RealmObject {
    @PrimaryKey
    private ObjectId _id = new ObjectId();
    private String name = "Task";
    @Required
    private String status = TaskStatus.Open.name();
    public void setStatus(TaskStatus status) {
        this.status = status.name();
    }
    public String getStatus() {
        return this.status;
    }
    public ObjectId get_id() {
        return _id;
    }
    public void set_id(ObjectId _id) {
        this._id = _id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Task(String _name) {
        this.name = _name;
    }
    public Task() {}
}

public enum TaskStatus {
    Open("Open"),
    InProgress("In Progress"),
    Complete("Complete");
    String displayName;
    TaskStatus(String displayName) {
        this.displayName = displayName;
    }
}

enum class TaskStatus(val displayName: String) {
    Open("Open"),
    InProgress("In Progress"),
    Complete("Complete"),
}
open class Task(_name: String = "Task", project: String = "My Project") : RealmObject() {
    @PrimaryKey
    var _id: ObjectId = ObjectId()
    var name: String = _name
    @Required
    var status: String = TaskStatus.Open.name
    var statusEnum: TaskStatus
        get() {
            // because status is actually a String and another client could assign an invalid value,
            // default the status to "Open" if the status is unreadable
            return try {
                TaskStatus.valueOf(status)
            } catch (e: IllegalArgumentException) {
                TaskStatus.Open
            }
        }
        set(value) { status = value.name }
}

Authenticate a User

Cuando se ha activado la autenticación anónima en la Interfaz de usuario Realm, los usuarios pueden iniciar sesión en la aplicación de inmediato sin proporcionar ninguna información de identificación:

Credentials credentials = Credentials.anonymous();
app.loginAsync(credentials, result -> {
    if (result.isSuccess()) {
        Log.v("QUICKSTART", "Successfully authenticated anonymously.");
        User user = app.currentUser();
        String partitionValue = "My Project";
        SyncConfiguration config = new SyncConfiguration.Builder(
                user,
                partitionValue)
            .build();
        uiThreadRealm = Realm.getInstance(config);
        addChangeListenerToRealm(uiThreadRealm);
        FutureTask<String> task = new FutureTask(new BackgroundQuickStart(app.currentUser()), "test");
        ExecutorService executorService = Executors.newFixedThreadPool(2);
        executorService.execute(task);
    } else {
        Log.e("QUICKSTART", "Failed to log in. Error: " + result.getError());
    }
});

val credentials: Credentials = Credentials.anonymous()
app.loginAsync(credentials) {
    if (it.isSuccess) {
        Log.v("QUICKSTART", "Successfully authenticated anonymously.")
        val user: User? = app.currentUser()
        val partitionValue: String = "My Project"
        val config = SyncConfiguration.Builder(user, partitionValue)
            .build()
        uiThreadRealm = Realm.getInstance(config)
        addChangeListenerToRealm(uiThreadRealm)
        val task : FutureTask<String> = FutureTask(BackgroundQuickStart(app.currentUser()!!), "test")
        val executorService: ExecutorService = Executors.newFixedThreadPool(2)
        executorService.execute(task)
    } else {
        Log.e("QUICKSTART", "Failed to log in. Error: ${it.error}")
    }
}

Realm provides many additional ways to authenticate, register, and link users.

Abrir un reino

Once you have enabled Sync and authenticated a user, you can open a synced realm. Use SyncConfiguration to control the specifics of how your application synchronizes data with App Services, including timeouts, synchronous reads and writes on the UI thread, and more.

String partitionValue = "My Project";
SyncConfiguration config = new SyncConfiguration.Builder(
        user,
        partitionValue)
    .build();
Realm backgroundThreadRealm = Realm.getInstance(config);

val partitionValue: String = "My Project"
val config = SyncConfiguration.Builder(user, partitionValue)
    .build()
val backgroundThreadRealm : Realm = Realm.getInstance(config)

Crear, leer, actualizar y eliminar objetos

Once you have opened a realm, you can modify the objects within that realm in a write transaction block.

Importante

Synchronous Reads and Writes on the UI Thread

By default, you can only read or write to a realm in your application's UI thread using asynchronous transactions. That is, you can only use Realm methods whose name ends with the word Async in the main thread of your Android application unless you explicitly allow the use of synchronous methods.

Esta restricción existe en beneficio de los usuarios de tu aplicación: realizar operaciones de lectura y escritura en el hilo de la Interfaz de Usuario puede generar interacciones lentas o no respondidas en la Interfaz de Usuario, por lo que generalmente es mejor gestionar estas operaciones de manera asíncrona o en un hilo en segundo plano. Sin embargo, si tu aplicación requiere el uso de lecturas o escrituras de realm síncronas en el hilo de la IU, puedes permitir explícitamente el uso de métodos síncronos con las siguientes opciones SyncConfiguration:

SyncConfiguration config = new SyncConfiguration.Builder(app.currentUser(), PARTITION)
        .allowQueriesOnUiThread(true)
        .allowWritesOnUiThread(true)
        .build();
Realm.getInstanceAsync(config, new Realm.Callback() {
    @Override
    public void onSuccess(Realm realm) {
        Log.v(
                "EXAMPLE",
                "Successfully opened a realm with reads and writes allowed on the UI thread."
        );
    }
});

val config = SyncConfiguration.Builder(app.currentUser(), PARTITION)
    .allowQueriesOnUiThread(true)
    .allowWritesOnUiThread(true)
    .build()
Realm.getInstanceAsync(config, object : Realm.Callback() {
    override fun onSuccess(realm: Realm) {
        Log.v("EXAMPLE", "Successfully opened a realm with reads and writes allowed on the UI thread.")
    }
})

To create a new Task, instantiate an instance of the Task class and add it to the realm in a write block:

Task task = new Task("New Task");
backgroundThreadRealm.executeTransaction (transactionRealm -> {
    transactionRealm.insert(task);
});

val task : Task = Task("New Task", partitionValue)
backgroundThreadRealm.executeTransaction { transactionRealm ->
    transactionRealm.insert(task)
}

Puedes recuperar una colección en vivo de todos los elementos en el Realm:

// all tasks in the realm
RealmResults<Task> tasks = backgroundThreadRealm.where(Task.class).findAll();

// all tasks in the realm
val tasks : RealmResults<Task> = backgroundThreadRealm.where<Task>().findAll()

You can also filter that collection using a filter:

// you can also filter a collection
RealmResults<Task> tasksThatBeginWithN = tasks.where().beginsWith("name", "N").findAll();
RealmResults<Task> openTasks = tasks.where().equalTo("status", TaskStatus.Open.name()).findAll();

// you can also filter a collection
val tasksThatBeginWithN : List<Task> = tasks.where().beginsWith("name", "N").findAll()
val openTasks : List<Task> = tasks.where().equalTo("status", TaskStatus.Open.name).findAll()

To modify a task, update its properties in a write transaction block:

Task otherTask = tasks.get(0);
// all modifications to a realm must happen inside of a write block
backgroundThreadRealm.executeTransaction( transactionRealm -> {
    Task innerOtherTask = transactionRealm.where(Task.class).equalTo("_id", otherTask.get_id()).findFirst();
    innerOtherTask.setStatus(TaskStatus.Complete);
});

val otherTask: Task = tasks[0]!!
// all modifications to a realm must happen inside of a write block
backgroundThreadRealm.executeTransaction { transactionRealm ->
    val innerOtherTask : Task = transactionRealm.where<Task>().equalTo("_id", otherTask._id).findFirst()!!
    innerOtherTask.status = TaskStatus.Complete.name
}

Finally, you can delete a task by calling the deleteFromRealm() method in a write transaction block:

Task yetAnotherTask = tasks.get(0);
ObjectId yetAnotherTaskId = yetAnotherTask.get_id();
// all modifications to a realm must happen inside of a write block
backgroundThreadRealm.executeTransaction( transactionRealm -> {
    Task innerYetAnotherTask = transactionRealm.where(Task.class).equalTo("_id", yetAnotherTaskId).findFirst();
    innerYetAnotherTask.deleteFromRealm();
});

val yetAnotherTask: Task = tasks.get(0)!!
val yetAnotherTaskId: ObjectId = yetAnotherTask._id
// all modifications to a realm must happen inside of a write block
backgroundThreadRealm.executeTransaction { transactionRealm ->
    val innerYetAnotherTask : Task = transactionRealm.where<Task>().equalTo("_id", yetAnotherTaskId).findFirst()!!
    innerYetAnotherTask.deleteFromRealm()
}

Esté atento a los cambios

You can watch a realm, collection, or object for changes by attaching a custom OrderedRealmCollectionChangeListener with the addChangeListener() method:

// all tasks in the realm
RealmResults<Task> tasks = uiThreadRealm.where(Task.class).findAllAsync();
tasks.addChangeListener(new OrderedRealmCollectionChangeListener<RealmResults<Task>>() {
    @Override
    public void onChange(RealmResults<Task> collection, OrderedCollectionChangeSet changeSet) {
        // process deletions in reverse order if maintaining parallel data structures so indices don't change as you iterate
        OrderedCollectionChangeSet.Range[] deletions = changeSet.getDeletionRanges();
        for (OrderedCollectionChangeSet.Range range : deletions) {
            Log.v("QUICKSTART", "Deleted range: " + range.startIndex + " to " + (range.startIndex + range.length - 1));
        }
        OrderedCollectionChangeSet.Range[] insertions = changeSet.getInsertionRanges();
        for (OrderedCollectionChangeSet.Range range : insertions) {
            Log.v("QUICKSTART", "Inserted range: " + range.startIndex + " to " + (range.startIndex + range.length - 1));                            }
        OrderedCollectionChangeSet.Range[] modifications = changeSet.getChangeRanges();
        for (OrderedCollectionChangeSet.Range range : modifications) {
            Log.v("QUICKSTART", "Updated range: " + range.startIndex + " to " + (range.startIndex + range.length - 1));                            }
    }
});

// all tasks in the realm
val tasks : RealmResults<Task> = realm.where<Task>().findAllAsync()
tasks.addChangeListener(OrderedRealmCollectionChangeListener<RealmResults<Task>> { collection, changeSet ->
    // process deletions in reverse order if maintaining parallel data structures so indices don't change as you iterate
    val deletions = changeSet.deletionRanges
    for (i in deletions.indices.reversed()) {
        val range = deletions[i]
        Log.v("QUICKSTART", "Deleted range: ${range.startIndex} to ${range.startIndex + range.length - 1}")
    }
    val insertions = changeSet.insertionRanges
    for (range in insertions) {
        Log.v("QUICKSTART", "Inserted range: ${range.startIndex} to ${range.startIndex + range.length - 1}")
    }
    val modifications = changeSet.changeRanges
    for (range in modifications) {
        Log.v("QUICKSTART", "Updated range: ${range.startIndex} to ${range.startIndex + range.length - 1}")
    }
})

Log Out

Once logged in, you can log out:

app.currentUser().logOutAsync(result -> {
    if (result.isSuccess()) {
        Log.v("QUICKSTART", "Successfully logged out.");
    } else {
        Log.e("QUICKSTART", "Failed to log out, error: " + result.getError());
    }
});

app.currentUser()?.logOutAsync() {
    if (it.isSuccess) {
        Log.v("QUICKSTART", "Successfully logged out.")
    } else {
        Log.e("QUICKSTART", "Failed to log out, error: ${it.error}")
    }
}

Ejemplo completo

Run the complete example by replacing the appId with your realm app ID. If you're running this project in a fresh Android Studio project, you can copy and paste this file into your application's MainActivity -- just remember to:

change the package declaration so it matches your project
Reemplace el marcador de posición de ID de aplicación con el ID de aplicación de su aplicación
actualiza las instrucciones de import para Task y TaskStatus si estás utilizando Java

Task.java

import io.realm.RealmObject;
import io.realm.annotations.PrimaryKey;
import io.realm.annotations.RealmClass;
import io.realm.annotations.Required;
import org.bson.types.ObjectId;
public class Task extends RealmObject {
    @PrimaryKey
    private ObjectId _id = new ObjectId();
    private String name = "Task";
    @Required
    private String status = TaskStatus.Open.name();
    public void setStatus(TaskStatus status) {
        this.status = status.name();
    }
    public String getStatus() {
        return this.status;
    }
    public ObjectId get_id() {
        return _id;
    }
    public void set_id(ObjectId _id) {
        this._id = _id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Task(String _name) {
        this.name = _name;
    }
    public Task() {}
}

TaskStatus.java

public enum TaskStatus {
    Open("Open"),
    InProgress("In Progress"),
    Complete("Complete");
    String displayName;
    TaskStatus(String displayName) {
        this.displayName = displayName;
    }
}

MainActivity.java

import io.realm.OrderedCollectionChangeSet;
import org.bson.types.ObjectId;
import android.os.Bundle;
import androidx.appcompat.app.AppCompatActivity;
import android.util.Log;
import io.realm.OrderedRealmCollectionChangeListener;
import io.realm.Realm;
import io.realm.RealmResults;
import io.realm.mongodb.App;
import io.realm.mongodb.AppConfiguration;
import io.realm.mongodb.Credentials;
import io.realm.mongodb.User;
import io.realm.mongodb.sync.SyncConfiguration;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
import java.util.concurrent.FutureTask;
import com.mongodb.realm.examples.model.Task;
import com.mongodb.realm.examples.model.TaskStatus;
public class MainActivity extends AppCompatActivity {
    Realm uiThreadRealm;
    App app;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        Realm.init(this); // context, usually an Activity or Application
        app = new App(new AppConfiguration.Builder(appID)
            .build());
        Credentials credentials = Credentials.anonymous();
        app.loginAsync(credentials, result -> {
            if (result.isSuccess()) {
                Log.v("QUICKSTART", "Successfully authenticated anonymously.");
                User user = app.currentUser();
                String partitionValue = "My Project";
                SyncConfiguration config = new SyncConfiguration.Builder(
                        user,
                        partitionValue)
                    .build();
                uiThreadRealm = Realm.getInstance(config);
                addChangeListenerToRealm(uiThreadRealm);
                FutureTask<String> task = new FutureTask(new BackgroundQuickStart(app.currentUser()), "test");
                ExecutorService executorService = Executors.newFixedThreadPool(2);
                executorService.execute(task);
            } else {
                Log.e("QUICKSTART", "Failed to log in. Error: " + result.getError());
            }
        });
    }
    private void addChangeListenerToRealm(Realm realm) {
        // all tasks in the realm
        RealmResults<Task> tasks = uiThreadRealm.where(Task.class).findAllAsync();
        tasks.addChangeListener(new OrderedRealmCollectionChangeListener<RealmResults<Task>>() {
            @Override
            public void onChange(RealmResults<Task> collection, OrderedCollectionChangeSet changeSet) {
                // process deletions in reverse order if maintaining parallel data structures so indices don't change as you iterate
                OrderedCollectionChangeSet.Range[] deletions = changeSet.getDeletionRanges();
                for (OrderedCollectionChangeSet.Range range : deletions) {
                    Log.v("QUICKSTART", "Deleted range: " + range.startIndex + " to " + (range.startIndex + range.length - 1));
                }
                OrderedCollectionChangeSet.Range[] insertions = changeSet.getInsertionRanges();
                for (OrderedCollectionChangeSet.Range range : insertions) {
                    Log.v("QUICKSTART", "Inserted range: " + range.startIndex + " to " + (range.startIndex + range.length - 1));                            }
                OrderedCollectionChangeSet.Range[] modifications = changeSet.getChangeRanges();
                for (OrderedCollectionChangeSet.Range range : modifications) {
                    Log.v("QUICKSTART", "Updated range: " + range.startIndex + " to " + (range.startIndex + range.length - 1));                            }
            }
        });
    }
    @Override
    protected void onDestroy() {
        super.onDestroy();
        // the ui thread realm uses asynchronous transactions, so we can only safely close the realm
        // when the activity ends and we can safely assume that those transactions have completed
        uiThreadRealm.close();
        app.currentUser().logOutAsync(result -> {
            if (result.isSuccess()) {
                Log.v("QUICKSTART", "Successfully logged out.");
            } else {
                Log.e("QUICKSTART", "Failed to log out, error: " + result.getError());
            }
        });
    }
    public class BackgroundQuickStart implements Runnable {
        User user;
        public BackgroundQuickStart(User user) {
            this.user = user;
        }
        @Override
        public void run() {
            String partitionValue = "My Project";
            SyncConfiguration config = new SyncConfiguration.Builder(
                    user,
                    partitionValue)
                .build();
            Realm backgroundThreadRealm = Realm.getInstance(config);
            Task task = new Task("New Task");
            backgroundThreadRealm.executeTransaction (transactionRealm -> {
                transactionRealm.insert(task);
            });
            // all tasks in the realm
            RealmResults<Task> tasks = backgroundThreadRealm.where(Task.class).findAll();
            // you can also filter a collection
            RealmResults<Task> tasksThatBeginWithN = tasks.where().beginsWith("name", "N").findAll();
            RealmResults<Task> openTasks = tasks.where().equalTo("status", TaskStatus.Open.name()).findAll();
            Task otherTask = tasks.get(0);
            // all modifications to a realm must happen inside of a write block
            backgroundThreadRealm.executeTransaction( transactionRealm -> {
                Task innerOtherTask = transactionRealm.where(Task.class).equalTo("_id", otherTask.get_id()).findFirst();
                innerOtherTask.setStatus(TaskStatus.Complete);
            });
            Task yetAnotherTask = tasks.get(0);
            ObjectId yetAnotherTaskId = yetAnotherTask.get_id();
            // all modifications to a realm must happen inside of a write block
            backgroundThreadRealm.executeTransaction( transactionRealm -> {
                Task innerYetAnotherTask = transactionRealm.where(Task.class).equalTo("_id", yetAnotherTaskId).findFirst();
                innerYetAnotherTask.deleteFromRealm();
            });
            // because this background thread uses synchronous realm transactions, at this point all
            // transactions have completed and we can safely close the realm
            backgroundThreadRealm.close();
        }
    }
}

MainActivity.kt

import org.bson.types.ObjectId
import android.os.Bundle
import androidx.appcompat.app.AppCompatActivity
import android.util.Log
import com.mongodb.realm.examples.YOUR_APP_ID
import io.realm.OrderedRealmCollectionChangeListener
import io.realm.Realm
import io.realm.RealmObject
import io.realm.RealmResults
import io.realm.annotations.PrimaryKey
import io.realm.annotations.Required
import io.realm.kotlin.where
import io.realm.mongodb.App
import io.realm.mongodb.AppConfiguration
import io.realm.mongodb.Credentials
import io.realm.mongodb.User
import io.realm.mongodb.sync.SyncConfiguration
import java.util.concurrent.ExecutorService
import java.util.concurrent.Executors
import java.util.concurrent.FutureTask
class MainActivity : AppCompatActivity() {
    lateinit var uiThreadRealm: Realm
    lateinit var app: App
    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        Realm.init(this) // context, usually an Activity or Application
        val appID : String = YOUR_APP_ID;
        app = App(AppConfiguration.Builder(appID)
                .build())
        val credentials: Credentials = Credentials.anonymous()
        app.loginAsync(credentials) {
            if (it.isSuccess) {
                Log.v("QUICKSTART", "Successfully authenticated anonymously.")
                val user: User? = app.currentUser()
                val partitionValue: String = "My Project"
                val config = SyncConfiguration.Builder(user, partitionValue)
                    .build()
                uiThreadRealm = Realm.getInstance(config)
                addChangeListenerToRealm(uiThreadRealm)
                val task : FutureTask<String> = FutureTask(BackgroundQuickStart(app.currentUser()!!), "test")
                val executorService: ExecutorService = Executors.newFixedThreadPool(2)
                executorService.execute(task)
            } else {
                Log.e("QUICKSTART", "Failed to log in. Error: ${it.error}")
            }
        }
    }
    fun addChangeListenerToRealm(realm : Realm) {
        // all tasks in the realm
        val tasks : RealmResults<Task> = realm.where<Task>().findAllAsync()
        tasks.addChangeListener(OrderedRealmCollectionChangeListener<RealmResults<Task>> { collection, changeSet ->
            // process deletions in reverse order if maintaining parallel data structures so indices don't change as you iterate
            val deletions = changeSet.deletionRanges
            for (i in deletions.indices.reversed()) {
                val range = deletions[i]
                Log.v("QUICKSTART", "Deleted range: ${range.startIndex} to ${range.startIndex + range.length - 1}")
            }
            val insertions = changeSet.insertionRanges
            for (range in insertions) {
                Log.v("QUICKSTART", "Inserted range: ${range.startIndex} to ${range.startIndex + range.length - 1}")
            }
            val modifications = changeSet.changeRanges
            for (range in modifications) {
                Log.v("QUICKSTART", "Updated range: ${range.startIndex} to ${range.startIndex + range.length - 1}")
            }
        })
    }
    override fun onDestroy() {
        super.onDestroy()
        // the ui thread realm uses asynchronous transactions, so we can only safely close the realm
        // when the activity ends and we can safely assume that those transactions have completed
        uiThreadRealm.close()
        app.currentUser()?.logOutAsync() {
            if (it.isSuccess) {
                Log.v("QUICKSTART", "Successfully logged out.")
            } else {
                Log.e("QUICKSTART", "Failed to log out, error: ${it.error}")
            }
        }
    }
    class BackgroundQuickStart(val user: User) : Runnable {
        override fun run() {
            val partitionValue: String = "My Project"
            val config = SyncConfiguration.Builder(user, partitionValue)
                .build()
            val backgroundThreadRealm : Realm = Realm.getInstance(config)
            val task : Task = Task("New Task", partitionValue)
            backgroundThreadRealm.executeTransaction { transactionRealm ->
                transactionRealm.insert(task)
            }
            // all tasks in the realm
            val tasks : RealmResults<Task> = backgroundThreadRealm.where<Task>().findAll()
            // you can also filter a collection
            val tasksThatBeginWithN : List<Task> = tasks.where().beginsWith("name", "N").findAll()
            val openTasks : List<Task> = tasks.where().equalTo("status", TaskStatus.Open.name).findAll()
            val otherTask: Task = tasks[0]!!
            // all modifications to a realm must happen inside of a write block
            backgroundThreadRealm.executeTransaction { transactionRealm ->
                val innerOtherTask : Task = transactionRealm.where<Task>().equalTo("_id", otherTask._id).findFirst()!!
                innerOtherTask.status = TaskStatus.Complete.name
            }
            val yetAnotherTask: Task = tasks.get(0)!!
            val yetAnotherTaskId: ObjectId = yetAnotherTask._id
            // all modifications to a realm must happen inside of a write block
            backgroundThreadRealm.executeTransaction { transactionRealm ->
                val innerYetAnotherTask : Task = transactionRealm.where<Task>().equalTo("_id", yetAnotherTaskId).findFirst()!!
                innerYetAnotherTask.deleteFromRealm()
            }
            // because this background thread uses synchronous realm transactions, at this point all
            // transactions have completed and we can safely close the realm
            backgroundThreadRealm.close()
        }
    }
}
enum class TaskStatus(val displayName: String) {
    Open("Open"),
    InProgress("In Progress"),
    Complete("Complete"),
}
open class Task(_name: String = "Task", project: String = "My Project") : RealmObject() {
    @PrimaryKey
    var _id: ObjectId = ObjectId()
    var name: String = _name
    @Required
    var status: String = TaskStatus.Open.name
    var statusEnum: TaskStatus
        get() {
            // because status is actually a String and another client could assign an invalid value,
            // default the status to "Open" if the status is unreadable
            return try {
                TaskStatus.valueOf(status)
            } catch (e: IllegalArgumentException) {
                TaskStatus.Open
            }
        }
        set(value) { status = value.name }
}

Salida

Running the above code should produce output resembling the following:

Successfully authenticated anonymously.
Updated range: 0 to 1
Deleted range: 0 to 1
Successfully logged out.

Bienvenido a la Docs de Atlas Device SDK