Android解決GreenDao 3.0以上數據庫升級的問題

Android開發必然會涉及到數據庫升級的問題，爲了避免升級後數據清除的問題，我們需要對greendao升級進行處理，這裏我使用的是GreenDaoUpgradeHelper.
使用步驟：
1.添加這個依賴

compile 'io.github.yuweiguocn:GreenDaoUpgradeHelper:v2.2.1'//升級數據庫

2.增加一個類繼承DaoMaster.OpenHelper

public class MyGreenDaoUpgradeOpenHelper extends DaoMaster.OpenHelper {
    public MyGreenDaoUpgradeOpenHelper(Context context, String name) {
        super(context, name);
    }

    @Override
    public void onUpgrade(Database db, int oldVersion, int newVersion) {
        MigrationHelper.migrate(db, new MigrationHelper.ReCreateAllTableListener() {

            @Override
            public void onCreateAllTables(Database db, boolean ifNotExists) {
                DaoMaster.createAllTables(db, ifNotExists);
            }

            @Override
            public void onDropAllTables(Database db, boolean ifExists) {
                DaoMaster.dropAllTables(db, ifExists);
            }
        }, UserInfoTableDao.class, VideoHistroyTableDao.class);
    }
}

這裏我們關注MigrationHelper.migrate這個方法的後面類參數即可，上面的UserInfoTableDao.class和VideoHistroyTableDao.class是之前我寫好表UserInfoTable和VideoHistroyTable之後編譯生成的，具體也可以查看你寫的生成目錄，我這裏是

3.初始化，改造下DaoMaster

        MigrationHelper.DEBUG = true; //如果你想查看日誌信息，請將DEBUG設置爲true
        MyGreenDaoUpgradeOpenHelper helper = new MyGreenDaoUpgradeOpenHelper(this, DB_NAME
                );
        DaoMaster  daoMaster = new DaoMaster(helper.getWritableDatabase());

4.注意後面加上混淆

-keepclassmembers class * extends org.greenrobot.greendao.AbstractDao {
    public static void dropTable(org.greenrobot.greendao.database.Database, boolean);
    public static void createTable(org.greenrobot.greendao.database.Database, boolean);
}