使用greenDAO进行开发总结

网上有很多介绍使用greenDAO的方法，看完之后不是很清楚，因为所有的讲解都是围绕其自身附带的例子，java文件也使用的是生成的，没有针对性，比如当接入第三方进行开发时，第三方的model是提供好的，而且可能不是普通的getter和setter，而是使用的public属性，还有就是项目移植，不用它的代码来升级框架层。所以我就没能使用它生成的文件来开发。

我的开发过程（前提是有自己的model，我以我的model：Status为例）：

1、引入DaoCore库工程，加入到你的项目库里面。

2、创建自己的DAO文件，继承AbstractDao<Status, Long> ，

2.1复写其中的部分方法，同时创建一个内部类

public static class Properties {

...

}

这个类里面是进行列的参数设置，为每一列创建一个Property对象，实例化这个对象时里面的参数分别为：

(int ordinal, Class<?> type, String name, boolean primaryKey, String columnName) 

ordinal：第几列

type：属于哪个model

name：属性名

primaryKey：是否主键

columnName：数据表中的列名

2.2建表和删除表的方法

 /** Creates the underlying database table. */    public static void createTable(SQLiteDatabase db, boolean ifNotExists) {        String constraint = ifNotExists? "IF NOT EXISTS ": "";        db.execSQL("建表语句自己写");    }    /** Drops the underlying database table. */    public static void dropTable(SQLiteDatabase db, boolean ifExists) {        String sql = "DROP TABLE " + (ifExists ? "IF EXISTS " : "") + "'"+TABLENAME+"'";        db.execSQL(sql);    }

3、使用给的例子里面的两个文件，master和session，在这两个上进行修改。

贴出我的，仔细看的话会发现这些是有规律的，自己添加的时候要按照这个规律来。

package com.yang.DBUtil;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteDatabase.CursorFactory;import android.database.sqlite.SQLiteOpenHelper;import android.util.Log;import com.yang.DBDAO.StatusDAO;import com.yang.DBDAO.UsersDAO;import de.greenrobot.dao.AbstractDaoMaster;import de.greenrobot.dao.identityscope.IdentityScopeType;// THIS CODE IS GENERATED BY greenDAO, DO NOT EDIT./** * Master of DAO (schema version 1000): knows all DAOs. */public class DaoMaster extends AbstractDaoMaster {public static final int SCHEMA_VERSION = 1;/** Creates underlying database table using DAOs. */public static void createAllTables(SQLiteDatabase db, boolean ifNotExists) {StatusDAO.createTable(db, ifNotExists);UsersDAO.createTable(db, ifNotExists);}/** Drops underlying database table using DAOs. */public static void dropAllTables(SQLiteDatabase db, boolean ifExists) {StatusDAO.dropTable(db, ifExists);UsersDAO.dropTable(db, ifExists);}public static abstract class OpenHelper extends SQLiteOpenHelper {public OpenHelper(Context context, String name, CursorFactory factory) {super(context, name, factory, SCHEMA_VERSION);}@Overridepublic void onCreate(SQLiteDatabase db) {Log.i("greenDAO", "Creating tables for schema version "+ SCHEMA_VERSION);createAllTables(db, false);}}/** WARNING: Drops all table on Upgrade! Use only during development. */public static class DevOpenHelper extends OpenHelper {public DevOpenHelper(Context context, String name, CursorFactory factory) {super(context, name, factory);}@Overridepublic void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {Log.i("greenDAO", "Upgrading schema from version " + oldVersion+ " to " + newVersion + " by dropping all tables");dropAllTables(db, true);onCreate(db);}}public DaoMaster(SQLiteDatabase db) {super(db, SCHEMA_VERSION);registerDaoClass(StatusDAO.class);registerDaoClass(UsersDAO.class);}public DaoSession newSession() {return new DaoSession(db, IdentityScopeType.Session, daoConfigMap);}public DaoSession newSession(IdentityScopeType type) {return new DaoSession(db, type, daoConfigMap);}}

package com.yang.DBUtil;import java.util.Map;import android.database.sqlite.SQLiteDatabase;import com.sina.weibo.sdk.openapi.models.Status;import com.sina.weibo.sdk.openapi.models.User;import com.yang.DBDAO.StatusDAO;import com.yang.DBDAO.UsersDAO;import de.greenrobot.dao.AbstractDao;import de.greenrobot.dao.AbstractDaoSession;import de.greenrobot.dao.identityscope.IdentityScopeType;import de.greenrobot.dao.internal.DaoConfig;// THIS CODE IS GENERATED BY greenDAO, DO NOT EDIT./** * {@inheritDoc} *  * @see de.greenrobot.dao.AbstractDaoSession */public class DaoSession extends AbstractDaoSession {private final DaoConfig statusDaoConfig;private final DaoConfig usersDaoConfig;private final StatusDAO statusDAO;private final UsersDAO usersDAO;public DaoSession(SQLiteDatabase db, IdentityScopeType type,Map<Class<? extends AbstractDao<?, ?>>, DaoConfig> daoConfigMap) {super(db);statusDaoConfig = daoConfigMap.get(StatusDAO.class).clone();statusDaoConfig.initIdentityScope(type);usersDaoConfig = daoConfigMap.get(UsersDAO.class).clone();usersDaoConfig.initIdentityScope(type);statusDAO = new StatusDAO(statusDaoConfig, this);usersDAO = new UsersDAO(usersDaoConfig, this);registerDao(Status.class, statusDAO);registerDao(User.class, usersDAO);}public void clear() {statusDaoConfig.getIdentityScope().clear();usersDaoConfig.getIdentityScope().clear();}public StatusDAO getStatusDAO() {return statusDAO;}public UsersDAO getUsersDAO() {return usersDAO;}}

4、使用它来建表

4.1普通的办法：

private SQLiteDatabase db;private DaoMaster daoMaster;private DaoSession daoSession;private NoteDao noteDao;

DevOpenHelper helper = new DaoMaster.DevOpenHelper(this, "notes-db", null);db = helper.getWritableDatabase();daoMaster = new DaoMaster(db);daoSession = daoMaster.newSession();noteDao = daoSession.getNoteDao();

4.2官方推荐的办法：

不用每次new一个session

4.2.1新建一个类，继承Application

package com.sina.Demo;import android.app.Application;import android.content.Context;import com.yang.DBUtil.DaoMaster;import com.yang.DBUtil.DaoMaster.OpenHelper;import com.yang.DBUtil.DaoSession;public class BaseApplication extends Application {private static BaseApplication mInstance;private static DaoMaster daoMaster;private static DaoSession daoSession;@Overridepublic void onCreate() {super.onCreate();if (mInstance == null)mInstance = this;}/** * 取得DaoMaster *  * @param context * @return */public static DaoMaster getDaoMaster(Context context) {if (daoMaster == null) {OpenHelper helper = new DaoMaster.DevOpenHelper(context,Constants.DBNAME, null);daoMaster = new DaoMaster(helper.getWritableDatabase());}return daoMaster;}/** * 取得DaoSession *  * @param context * @return */public static DaoSession getDaoSession(Context context) {if (daoSession == null) {if (daoMaster == null) {daoMaster = getDaoMaster(context);}daoSession = daoMaster.newSession();}return daoSession;}}

4.2.2在AndroidManifest.xml中进行配置

application的属性name指向这个类。

4.2.3调用来生成数据库

application=(BaseApplication) getApplication();daoMaster = application.getDaoMaster(MyHomePage.this);daoSession = application.getDaoSession(MyHomePage.this);statusDAO = daoSession.getStatusDAO();usersDAO = daoSession.getUsersDAO();

拿到dao就可以进行数据操作了。

结束。

注意：它的数据库版本控制是在master类中，参数名叫：SCHEMA_VERSION，新的一次的版本号不能低于之前运行时的版本号，除非卸载重装。