@linux1s1s 2016-12-01T10:26:28.000000Z 字数 6853 阅读 1875

Android ORM - GreenDAO

AndroidRefine 2016-11

系列博文
Android ORM - GreenDAO
Android ORM - OrmLite

ORM/DAO

此处输入图片的描述

Demo

下面以一个简单的Demo演示一下如何使用GreenDAO

配置和资源文件

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="okhttp.mutex.com.orm_demo">
    <application
        android:name=".ORMApplication"
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />
                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>
</manifest>

Top-level build.gradle

// Top-level build file where you can add configuration options common to all sub-projects/modules.
buildscript {
    repositories {
        jcenter()
        mavenCentral()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.2.2'
        classpath 'org.greenrobot:greendao-gradle-plugin:3.2.0'
        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}
allprojects {
    repositories {
        jcenter()
    }
}
task clean(type: Delete) {
    delete rootProject.buildDir
}

Second-level build.gradle

apply plugin: 'com.android.application'
apply plugin: 'org.greenrobot.greendao'
android {
    compileSdkVersion 24
    buildToolsVersion "24.0.0"
    defaultConfig {
        applicationId "okhttp.mutex.com.orm_demo"
        minSdkVersion 15
        targetSdkVersion 24
        versionCode 1
        versionName "1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
    }
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }
    greendao{
        schemaVersion 1
        daoPackage 'com.admom.mygreendaotest'
        targetGenDir 'src/main/java'
    }
}
dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile 'com.android.support:appcompat-v7:24.2.1'
    testCompile 'junit:junit:4.12'
    compile 'org.greenrobot:greendao:3.2.0'
}

以上配置重点关注一下信息：
- 加入greendao插件
- 配置greendao生成代码的目录地址，包名以及版本号
- 配置greendao的依赖地址

另外以上配置greendao信息的相关字段简要说明如下：

schemaVersion：数据库schema版本，也可以理解为数据库版本号

daoPackage：设置DaoMaster 、DaoSession、Dao包名

targetGenDir：设置DaoMaster 、DaoSession、Dao目录

targetGenDirTest：设置生成单元测试目录

generateTests：设置自动生成单元测试用例

源码

先生成POJO类，greendao通过注解的形式自动生成DAO类

Info.java

package okhttp.mutex.com.orm_demo;
import org.greenrobot.greendao.annotation.Entity;
import org.greenrobot.greendao.annotation.Id;
import org.greenrobot.greendao.annotation.Generated;
@Entity
public class Info {
    @Id(autoincrement = true)
    private long id;
    private String name;
    private int age;
    ...
}

编译完以后会自动生成DaoMaster, DaoSession, XXXDao等类，并把这些类自动放到指定的目录和包名下，如图所示：

此处输入图片的描述

我们需要进一步了解注解的相关意思

实体@Entity注解
schema：告知GreenDao当前实体属于哪个schema
active：标记一个实体处于活动状态，活动实体有更新、删除和刷新方法
nameInDb：在数据中使用的别名，默认使用的是实体的类名
indexes：定义索引，可以跨越多个列
createInDb：标记创建数据库表

@Id :主键 Long型，可以通过@Id(autoincrement = true)设置自增长

@Property：设置一个非默认关系映射所对应的列名，默认是的使用字段名举例：@Property (nameInDb="name")

@NotNul：设置数据库表当前列不能为空

@Transient ：添加次标记之后不会生成数据库表的列

@Index：使用@Index作为一个属性来创建一个索引，通过name设置索引别名，也可以通过unique给索引添加约束

@Unique：向数据库列添加了一个唯一的约束

@ToOne：定义与另一个实体（一个实体对象）的关系

@ToMany：定义与多个实体对象的关系

GreenDAOManager.java

package okhttp.mutex.com.orm_demo;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import com.admom.mygreendaotest.DaoMaster;
public class GreenDAOManager {
    private static GreenDAOManager sINSTANCE;
    private final DaoMaster.DevOpenHelper mHelper;
    private GreenDAOManager(Context context, String name) {
        mHelper = new DaoMaster.DevOpenHelper(context, name, null);
    }
    public static void createInstance(Context context, String name) {
        if (sINSTANCE == null) {
            synchronized (GreenDAOManager.class) {
                if (sINSTANCE == null) {
                    sINSTANCE = new GreenDAOManager(context, name);
                }
            }
        }
    }
    public static GreenDAOManager getInstance() {
        return sINSTANCE;
    }
    public SQLiteDatabase getReadableDatabase() {
        return mHelper.getReadableDatabase();
    }
    public SQLiteDatabase getWritableDatabase() {
        return mHelper.getWritableDatabase();
    }
}

InfoDAOHelper.java

package okhttp.mutex.com.orm_demo;
import com.admom.mygreendaotest.DaoMaster;
import com.admom.mygreendaotest.DaoSession;
import com.admom.mygreendaotest.InfoDao;
import org.greenrobot.greendao.query.QueryBuilder;
import java.util.List;
public class InfoDAOHelper {
    private InfoDAOHelper() {
        //Do Nothing
    }
    /**
     * 插入一条数据
     *
     * @param info
     */
    public static void insertInfo(Info info) {
        if (info == null)
            return;
        InfoDao infoDao = obtainWritableInfoDao();
        infoDao.insert(info);
    }
    /**
     * 插入一组数据
     *
     * @param infoList
     */
    public static void insertInfo(List<Info> infoList) {
        if (infoList == null || infoList.isEmpty())
            return;
        InfoDao info = obtainWritableInfoDao();
        info.insertInTx(infoList);
    }
    /**
     * 删除一组数据
     *
     * @param info
     */
    public static void deleteInfo(Info info) {
        if (info == null)
            return;
        InfoDao dao = obtainWritableInfoDao();
        dao.delete(info);
    }
    /**
     * 更新一组数据
     *
     * @param info
     */
    public static void update(Info info) {
        if (info == null)
            return;
        InfoDao dao = obtainWritableInfoDao();
        dao.update(info);
    }
    /**
     * 查询数据列表
     *
     * @return
     */
    public static List<Info> queryInfoList() {
        InfoDao dao = obtainReadableInfoDao();
        QueryBuilder<Info> builder = dao.queryBuilder();
        return builder.list();
    }
    /**
     * 查询符合条件的数据列表
     *
     * @param age
     * @return
     */
    public static List<Info> queryInfoList(int age) {
        InfoDao dao = obtainReadableInfoDao();
        QueryBuilder<Info> builder = dao.queryBuilder();
        builder.where(InfoDao.Properties.Age.eq(age)).orderAsc(InfoDao.Properties.Age);
        return builder.list();
    }
    private static InfoDao obtainWritableInfoDao() {
        DaoMaster master = new DaoMaster(GreenDAOManager.getInstance().getWritableDatabase());
        DaoSession session = master.newSession();
        return session.getInfoDao();
    }
    private static InfoDao obtainReadableInfoDao() {
        DaoMaster master = new DaoMaster(GreenDAOManager.getInstance().getReadableDatabase());
        DaoSession session = master.newSession();
        return session.getInfoDao();
    }
}

ORMApplication.java

package okhttp.mutex.com.orm_demo;
import android.app.Application;
public class ORMApplication extends Application {
    @Override
    public void onCreate() {
        super.onCreate();
        GreenDAOManager.createInstance(this, "db_test_name_4");
    }
}

MainActivity.java

package okhttp.mutex.com.orm_demo;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import java.util.List;
public class MainActivity extends AppCompatActivity {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initInfo();
        queryOri();
        queryOri(21);
        updateOri();
        deleteOri();
    }
    private void updateOri() {
        Info info = new Info(1, "name" + 1, 2 + 20);
        InfoDAOHelper.update(info);
        queryOri(22);
    }
    private void deleteOri() {
        Info info = new Info(1, "name" + 1, 1 + 20);
        InfoDAOHelper.deleteInfo(info);
        queryOri(21);
    }
    private void queryOri(int age) {
        List<Info> list = InfoDAOHelper.queryInfoList(age);
        for (Info info : list) {
            Log.w("mutex", age + " is : " + info.toString());
        }
    }
    private void queryOri() {
        List<Info> list = InfoDAOHelper.queryInfoList();
        for (Info info : list) {
            Log.i("mutex", info.toString());
        }
    }
    private void initInfo() {
        for (int i = 0; i < 10; i++) {
            Info info = new Info(i, "name" + i, i + 20);
            InfoDAOHelper.insertInfo(info);
        }
    }
}

验证结果

此处输入图片的描述

以上验证符合预期。

参考文章：
GreenDAO Website Github Doc Ori
OrmLite Website Github

Android ORM - GreenDAO

ORM/DAO

Demo

配置和资源文件

AndroidManifest.xml

Top-level build.gradle

Second-level build.gradle

源码

Info.java

GreenDAOManager.java

InfoDAOHelper.java

ORMApplication.java

MainActivity.java

验证结果

内容目录