GreenDao 应用

1. 简介

屏幕快照 2018-04-14 10.36.40.png

2. 使用方式

2. 1 在Project的buil.gradle里面添加配置项

buildscript {  
    repositories {        
        jcenter()       
        mavenCentral()   
    }    
    dependencies {        
        classpath 'com.android.tools.build:gradle:2.1.0'         
        classpath 'org.greenrobot:greendao-gradle-plugin:3.1.0'  
    }
}

2.2 在Module里面的dependencies里面添加

apply plugin: 'org.greenrobot.greendao'
...

greendao{
        schemaVersion 1
        targetGenDir 'src/main/java/'
}
compile'org.greenrobot:greendao:3.1.0'
compile'org.greenrobot:greendao-generator:3.1.0'

2.3 新建User.java

@Entity
public class User {
    @Id
    private Long id;
    @Property(nameInDb = "USERNAME")
    private String username;
    @Property(nameInDb = "NICKNAME")
    private String nickname;
}

2.4 在Application类之中添加DaoSession对象

private DaoSession daoSession;
@Override
public void onCreate() {
    super.onCreate();
    DaoMaster.DevOpenHelper helper = new 
    DaoMaster.DevOpenHelper(this,"test.db",null);
    Database db = helper.getWritableDb();
    daoSession = new DaoMaster(db).newSession();
}

public DaoSession getDaoSession() {
    return daoSession;
}

2.5 数据库的CURD操作

private DaoSession daoSessin;
private UserDao dao;

daoSessin = ((MyApplication) getApplication()).getDaoSession();
dao = daoSessin.getUserDao();
// 增加
private void add() {
    User addUser = new User();
    addUser.setUsername("xiaoming");
    addUser.setNickname("angle");
    dao.insert(addUser);
    Toast.makeText(this,"add success.",Toast.LENGTH_SHORT).show();
}

//删除
private void delete() {
    List<User> deleteList = dao.queryBuilder().where(
    UserDao.Properties
    .Username.eq("xiaoming"))
    .build().list();
    for (User u : deleteList) {
        dao.delete(u);
    }
    Toast.makeText(this,"delete success.",Toast.LENGTH_SHORT).show();
}

//修改
private void modify() {
    List<User> updateList = dao.queryBuilder().where(UserDao.Properties.Username
                            .eq("xiaoming"))
                            .build().list();
    for (User u : updateList) {
        u.setNickname("updated angle");
        dao.update(u);
    }
    Toast.makeText(this,"modify success.",Toast.LENGTH_SHORT).show();
}

//查找
private void select() {
    Query<User> userQuery = dao.queryBuilder()
                           .orderAsc(UserDao.Properties.Id)
                           .build();
    List<User> users = userQuery.list();
    String res = "";
    for (User u : users) {
        res += u.toString();
        res += "\r\n";
    }
    message.setText(res);
}

更多内容

1. GreenDAO3.0应用指南
2. Android SQLite详解