Realm的入门使用
一.介绍
Realm是一个不错的手机平台上的数据库,支持多种编程环境,如:Java、Object-C、React Native、Swift、Xamari等。
Realm的官网:https://realm.io/
github地址:https://github.com/realm
realm-java库的文档:https://realm.io/docs/java/la...
二.使用
1)配置:
//1.工程gradle buildscript { repositories { jcenter() } dependencies { //1. 添加realm插件 classpath "io.realm:realm-gradle-plugin:1.2.0" } } //2. app的gradle apply plugin: 'realm-android' dependencies { compile 'io.realm:realm-android-library:1.2.0' }
2)数据块操作实体类
package com.peter.schoolmarket.data.pojo; import java.io.Serializable; import io.realm.RealmObject; import io.realm.annotations.PrimaryKey; import io.realm.annotations.Required; /** * Created by PetterChen on 2017/4/10. */ public class User extends RealmObject implements Serializable { @PrimaryKey //主键id private int id;// private String username;//用户名 private String password;//用户密码 private String phone;//手机号 private String imgUrl;//头像地址 public User() { // } public void setId(int id) { this.id = id; } public void setUsername(String username) { this.username = username; } public void setPassword(String password) { this.password = password; } public void setPhone(String phone) { this.phone = phone; } public void setImgUrl(String imgUrl) { this.imgUrl = imgUrl; } public int getId() { return id; } public String getUsername() { return username; } public String getPassword() { return password; } public String getPhone() { return phone; } public String getImgUrl() { return imgUrl; } }
3)初始化
//Realm初始化,这是默认初始化,可以自定义初始化 Realm.init(this);//this表示上下文 RealmConfiguration config = new RealmConfiguration.Builder().build();//可以修改 Realm.setDefaultConfiguration(config);
4)数据库操作
可以使用事务或者事务块,对于事务块,有同步的和异步的,如果使用异步事务块,需要手动关闭
//增,事务增 Realm realm=Realm.getDefaultInstance(); realm.beginTransaction(); realm.copyToRealm(user); realm.commitTransaction(); //增,事务块增 Realm mRealm=Realm.getDefaultInstance(); mRealm.executeTransaction(new Realm.Transaction() { @Override public void execute(Realm realm) { realm.copyToRealm(user); } }); //删,事务块删 Realm mRealm=Realm.getDefaultInstance(); final RealmResults<Dog> dogs= mRealm.where(Dog.class).findAll(); mRealm.executeTransaction(new Realm.Transaction() { @Override public void execute(Realm realm) { Dog dog=dogs.get(5); dog.deleteFromRealm(); //删除第一个数据 dogs.deleteFirstFromRealm(); //删除最后一个数据 dogs.deleteLastFromRealm(); //删除位置为1的数据 dogs.deleteFromRealm(1); //删除所有数据 dogs.deleteAllFromRealm(); } }); //同理,也可以使用事务删 //查,查询全部 Realm mRealm=Realm.getDefaultInstance(); RealmResults<Dog> dogs = mRealm.where(Dog.class).findAll(); List<Dog> list = mRealm.copyFromRealm(dogs); //查,条件查询 Realm mRealm=Realm.getDefaultInstance(); Dog dog = mRealm.where(Dog.class).equalTo("id", id).findFirst(); //改 Realm mRealm=Realm.getDefaultInstance(); Dog dog = mRealm.where(Dog.class).equalTo("id", id).findFirst(); mRealm.beginTransaction(); dog.setName(newName); mRealm.commitTransaction();
三.最后
这篇博文算不上是原创,都是参考其它博文写的,只是为了以后自己有用到Realm时,可以不用再去查资料。
参考博文:
http://blog.csdn.net/fwt336/a...
http://www.cnblogs.com/liushi...
http://www.jianshu.com/p/fdc9...
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