singleLine0的GreenDao学习

参考：https://juejin.im/post/5959b5bcf265da6c4d1bb245

1. 配置

• build.gradle(Project)

buildscript {
    repositories {
        ......
        mavenCentral()     // add repository，因为无法下载添加仓库
        google()
    }
    dependencies {
       ......
       classpath 'org.greenrobot:greendao-gradle-plugin:3.2.2'   //添加插件
    }
}

allprojects {
    repositories {
        ......
        maven {
            //url "https://maven.google.com"    //遇到无法下载的情况
            url "http://repo1.maven.org/maven2"
        }
    }
}

• build.gradle(Module)

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

android {......}

dependencies {
    ......
    implementation 'org.greenrobot:greendao:3.2.2'   //添加依赖
}

greendao {
    schemaVersion 1 //数据库版本号
    daoPackage 'com.example.xjyfa.test1129.db'// 设置DaoMaster、DaoSession、Dao 包名
    targetGenDir 'src/main/java'//设置DaoMaster、DaoSession、Dao目录，就是包的目录
}

• sync同步

2. 初始化

• 使用注解，新建Entity类，然后make，会自动生成目录，注：db目录都是自动生成的。

package com.example.xjyfa.test1129;

import org.greenrobot.greendao.annotation.Entity;
import org.greenrobot.greendao.annotation.Id;
import org.greenrobot.greendao.annotation.Generated;

@Entity
public class Book {
    @Id
    private String name;    //author，page省略
    public String getName() {return name;}
    public void setName(String name) {this.name = name;}
    
    //以下为make后，自动生成！！！
    @Generated(hash = 1742999289)
    public Book(String name, String author, int page) {
        this.name = name;
        this.author = author;
        this.page = page;
    }
    @Generated(hash = 1839243756)
        public Book() {
        }

image.png

• 数据库初始化，得到DaoSession，通常写在Application的onCreate()中
• 有个小坑，要在清单文件配置application：name 属性

......
public class MyApp extends Application {
    private DaoSession daoSession;

    @Override
    public void onCreate() {
        super.onCreate();
        initGreenDao();
    }

    //初始化GreenDao
    private void initGreenDao() {
        DaoMaster.DevOpenHelper helper = new DaoMaster.DevOpenHelper(this,"test.db");
        Database database = helper.getWritableDb();
        DaoMaster daoMaster = new DaoMaster(database);
        daoSession = daoMaster.newSession();
    }

    //获取daoSession
    public DaoSession getDaoSession() {
        return daoSession;
    }
}

3. 基本使用

• 获取entityDao表

        //获取entityDao
        MyApp myApp = (MyApp) getApplication();
        DaoSession daoSession= myApp.getDaoSession();
        BookDao bookDao = daoSession.getBookDao();

• 增删查改操作

        //新建一个book实例
        Book book = new Book();
        book.setName("go");
        book.setAuthor("zard");
        book.setPage(486);
        //部分操作
        bookDao.insert(book);   //插入book
        bookDao.insertOrReplace(book);  //插入或者替换book,???怎么确定重复
        bookDao.delete(book);   //删除
        bookDao.deleteByKey("go");  //???
        bookDao.update(book);   //更新
        bookDao.loadAll();      //返回list
        bookDao.loadByRowId(1); //???
        //两种方式，查询页码大于300的书
        bookDao.queryRaw("where page > ?","300");    // SQL语句
        QueryBuilder builder = bookDao.queryBuilder();  //greedDao的api
        builder.where(BookDao.Properties.Page.gt(300)).build().list();

4. 注解

5 实际应用