Realm Java
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入门
先决条件
- Android Studio 1.5.1或更高版本
- JDK 7.0或更高版本
- 最新版本的Android SDK
- Android API等级9或更高（Android 2.3及更高版本）
注意： Realm不支持Android以外的Java。咱们再也不支持Eclipse做为IDE; 请迁移到Android Studio。java
安装
将Realm安装为Gradle插件。react
步骤1：将类路径依赖项添加到项目级build.gradle文件。linux
buildscript { repositories { jcenter() } dependencies { classpath "io.realm:realm-gradle-plugin:5.12.0" } }
在build.gradle此处查找项目级别文件：android
第2步：将realm-android插件应用到应用程序级build.gradle文件的顶部。git
apply plugin: 'realm-android'
在build.gradle此处查找应用程序级别文件：github
完成这两项更改后，只需刷新gradle依赖项便可。若是您从早期版本的Realm升级v0.88，则可能还须要清理gradle项目（./gradlew clean）。数据库
build.gradle在此处查找两个已修改文件的示例：npm
您是否但愿使用Realm Mobile Platform同步全部Realm数据库？全部与同步相关的文档已移至咱们的平台文档中编程
其余构建系统
不支持Maven和Ant构建系统。咱们正在跟踪在GitHub上支持它们的兴趣：
ProGuard配置做为Realm库的一部分提供。这意味着您无需向ProGuard配置添加任何Realm特定规则。
样品
Realm Java容许您以安全，持久和快速的方式有效地编写应用程序的模型层。这是它的样子：
// Define your model class by extending RealmObject public class Dog extends RealmObject { private String name; private int age; // ... Generated getters and setters ... } public class Person extends RealmObject { @PrimaryKey private long id; private String name; private RealmList<Dog> dogs; // Declare one-to-many relationships // ... Generated getters and setters ... } // Use them like regular java objects Dog dog = new Dog(); dog.setName("Rex"); dog.setAge(1); // Initialize Realm (just once per application) Realm.init(context); // Get a Realm instance for this thread Realm realm = Realm.getDefaultInstance(); // Query Realm for all dogs younger than 2 years old final RealmResults<Dog> puppies = realm.where(Dog.class).lessThan("age", 2).findAll(); puppies.size(); // => 0 because no dogs have been added to the Realm yet // Persist your data in a transaction realm.beginTransaction(); final Dog managedDog = realm.copyToRealm(dog); // Persist unmanaged objects Person person = realm.createObject(Person.class); // Create managed objects directly person.getDogs().add(managedDog); realm.commitTransaction(); // Listeners will be notified when data changes puppies.addChangeListener(new OrderedRealmCollectionChangeListener<RealmResults<Dog>>() { @Override public void onChange(RealmResults<Dog> results, OrderedCollectionChangeSet changeSet) { // Query results are updated in real time with fine grained notifications. changeSet.getInsertions(); // => [0] is added. } }); // Asynchronously update objects on a background thread realm.executeTransactionAsync(new Realm.Transaction() { @Override public void execute(Realm bgRealm) { Dog dog = bgRealm.where(Dog.class).equalTo("age", 1).findFirst(); dog.setAge(3); } }, new Realm.Transaction.OnSuccess() { @Override public void onSuccess() { // Original queries and Realm objects are automatically updated. puppies.size(); // => 0 because there are no more puppies younger than 2 years old