在将apk发包出去后需要改动Entity的元素,就需要升级数据库。
这时看具体需求,一是不需要原有数据,清除数据库;二是需要保留原有数据。
greendao默认使用的是第一种:
Daomaster:
public static class DevOpenHelper extends OpenHelper {
public DevOpenHelper(Context context, String name) {
super(context, name);
}
public DevOpenHelper(Context context, String name, CursorFactory factory) {
super(context, name, factory);
}
@Override
public void onUpgrade(Database db, int oldVersion, int newVersion) {
Log.i("greenDAO", "Upgrading schema from version " + oldVersion + " to " + newVersion + " by dropping all tables");
dropAllTables(db, true);
onCreate(db);
}
}
这里只说第二种情况。
那么需要升级需要如下操作:
- 自定义 Daomaster ,在 Application中申明
- 更改数据库版本号
- 添加需要增加的字段
在 CameraTime 中增加 test属性
@Entity
public class CameraTime {
@Id
private Long id;
private String time;
private String standUuid;
public String test;
}
**MyDaoMaster: **
import android.content.Context; import android.database.sqlite.SQLiteDatabase; import android.util.Log; import org.greenrobot.greendao.AbstractDaoMaster; import org.greenrobot.greendao.AbstractDaoSession; import org.greenrobot.greendao.database.Database; import org.greenrobot.greendao.database.DatabaseOpenHelper; import org.greenrobot.greendao.identityscope.IdentityScopeType; /** * Created by zhangli * * @time 2018/1/5 */ public class MyDaoMaster extends AbstractDaoMaster { public static final int SCHEMA_VERSION = 2; public MyDaoMaster(Database db, int schemaVersion) { super(db, schemaVersion); } @Override public AbstractDaoSession newSession() { return null; } @Override public AbstractDaoSession newSession(IdentityScopeType type) { return null; } public static void createAllTables(Database db, boolean ifNotExists) { CameraEntityDao.createTable(db, ifNotExists); CameraTimeDao.createTable(db, ifNotExists); FaroEntityDao.createTable(db, ifNotExists); FaroFileDao.createTable(db, ifNotExists); FloorPlanPictureDao.createTable(db, ifNotExists); PictureMatrixDao.createTable(db, ifNotExists); ProjectDao.createTable(db, ifNotExists); StandingEntityDao.createTable(db, ifNotExists); UpDataIdDao.createTable(db, ifNotExists); UserDao.createTable(db, ifNotExists); ImageRowDao.createTable(db, ifNotExists); } /** Drops underlying database table using DAOs. */ public static void dropAllTables(Database db, boolean ifExists) { CameraEntityDao.dropTable(db, ifExists); CameraTimeDao.dropTable(db, ifExists); FaroEntityDao.dropTable(db, ifExists); FaroFileDao.dropTable(db, ifExists); FloorPlanPictureDao.dropTable(db, ifExists); PictureMatrixDao.dropTable(db, ifExists); ProjectDao.dropTable(db, ifExists); StandingEntityDao.dropTable(db, ifExists); UpDataIdDao.dropTable(db, ifExists); UserDao.dropTable(db, ifExists); ImageRowDao.dropTable(db, ifExists); } public static abstract class OpenHelper extends DatabaseOpenHelper { public OpenHelper(Context context, String name) { super(context, name, SCHEMA_VERSION); } public OpenHelper(Context context, String name, SQLiteDatabase.CursorFactory factory) { super(context, name, factory, SCHEMA_VERSION); } @Override public void onCreate(Database 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) { super(context, name); } public DevOpenHelper(Context context, String name, SQLiteDatabase.CursorFactory factory) { super(context, name, factory); } @Override public void onUpgrade(Database db, int oldVersion, int newVersion) { Log.i("greenDAO", "Upgrading schema from version " + oldVersion + " to " + newVersion + " by dropping all tables"); switch (oldVersion) { case 1: CameraTimeDao.createTable(db, true); db.execSQL("ALTER TABLE 'CAMERA_TIME' ADD 'TEST' TEXT;"); break; } } } }
在 onUpgrade 方法中,当旧版本号为1时,增加一个 test 的字段在 CameraTime 表中。
不知道数据库表的命名规则的话,可以将数据库导出本地打开看即可。
在 MyDaoMashter 和 build.gradle 中改变版本号
greendao {
schemaVersion 2
daoPackage 'com.build.scan.greendao.gen'
targetGenDir 'src/main/java'
}
apk安装在版本号为1的的时候即可生效。