简介
GreenDAO是一个轻量、快速的ORM解决方案,它能高效地将对象映射到SQLite数据库,目前升级到了3.1版本,相较于之前的版本来说,易用性大幅度增加了,不需要一些麻烦的配置,详情参考官方文档 http://greenrobot.org/greendao/features/
1. 导入依赖
在project的build.gradle中插入:
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath 'org.greenrobot:greendao-gradle-plugin:3.1.0'
}
}
在module的build.gradle中插入:
buildscript {
repositories {
mavenCentral()
}
dependencies {
classpath 'org.greenrobot:greendao-gradle-plugin:3.1.0'
}
}
2. 编写需要存储对象的实体类
/**
* Created by GongCheng on 2016/8/20.
* 联系人数据库实体类
*/
@Entity
public class Contact {
@Id
private Long id; //注意Id必须是包装类
@NonNull
private String name;
private String number;
}
3. 编译项目
直接Rebuild,发现生成了下面这些文件
而刚才写的实体类也变成下面这样
**
* Created by GongCheng on 2016/8/20.
* 联系人数据库实体类
*/
@Entity
public class Contact {
@Id
private Long id;
@NonNull
private String name;
private String number;
public String getNumber() {
return this.number;
}
public void setNumber(String number) {
this.number = number;
}
public String getName() {
return this.name;
}
public void setName(String name) {
this.name = name;
}
public Long getId() {
return this.id;
}
public void setId(Long id) {
this.id = id;
}
@Generated(hash = 212132701)
public Contact(Long id, @NonNull String name, String number) {
this.id = id;
this.name = name;
this.number = number;
}
@Generated(hash = 672515148)
public Contact() {
}
}
这些都是通过插件生成的,不要随意去改动
4.初始化
初始化工作一般放在项目的Application里面执行
/**
* Created by GongCheng on 2016/8/5.
*/
public class MainApplication extends Application {
private static MainApplication INSTANCE ;
private DaoSession daoSession;
public static MainApplication getInstance(){
return INSTANCE;
}
@Override
public void onCreate() {
super.onCreate();
INSTANCE = this;
//初始化SharedPreferences
SharedPreferencesUtils.init();
//初始化GreenDao
DaoMaster.DevOpenHelper helper = new DaoMaster.DevOpenHelper(this,"contacts-db");
Database db = helper.getWritableDb();
daoSession = new DaoMaster(db).newSession();
}
//得到DaoSession
public DaoSession getDaoSession() {
return daoSession;
}
}
5.正式使用
//Contact的查询器
private Query contactQuery;
//ContactDao
private ContactDao contactDao;
/**
* 初始化Dao
*/
private void initDao() {
//得到ContactDao
DaoSession daoSession= MainApplication.getInstance().getDaoSession();
contactDao= daoSession.getContactDao();
//查询所有联系人(通过姓名)
contactQuery = contactDao.queryBuilder().orderAsc(ContactDao.Properties.Name).build();
updateContacts();
}
具体操作
//查询
List notes = notesQuery.list();
//添加
Contact contact = new Contact(null,name,number);
contactDao.insert(contact);
//删除
contactDao.deleteByKey(contactId);
还有一些其他操作没有一一列举了,GreenDao也提供了对RxJava的支持