如何解决拥有SQLite数据库和onUpgrade
| 我已使用本教程来为Android创建并填充我自己的sqlite数据库。 http://www.reigndesign.com/blog/using-your-own-sqlite-database-in-android-applications 但是,使用这些确切的方法意味着数据库不会使用以下代码升级private static final int DB_Version = 2;
public DbConnector(Context context){
super(context,DB_Name,null,DB_Version);
this.context = context;
}
实际上,永不调用onUpgrade()方法:
感谢您的帮助
解决方法
这是对Joe Masilotti的感谢
http://www.reigndesign.com/blog/using-your-own-sqlite-database-in-android-applications/comment-page-2/
private static final int DATABASE_VERSION = 1;
将构造函数更改为:
public DataBaseHelper(Context context) {
super(context,DB_NAME,null,DATABASE_VERSION);
this.myContext = context;
}
将ѭ3更改为(感谢@kondortek):
public void createDataBase() throws IOException {
boolean dbExist = checkDataBase();
if (dbExist) {
Log.v(“DB Exists”,“db exists”);
// By calling this method here onUpgrade will be called on a
// writeable database,but only if the version number has been
// bumped
this.getWritableDatabase();
}
dbExist = checkDataBase();
if (!dbExist) {
// By calling this method and empty database will be created into
// the default system path of your application so we are gonna be
// able to overwrite that database with our database.
this.getReadableDatabase();
try {
copyDataBase();
} catch (IOException e) {
throw new Error(“Error copying database”);
}
}
}
将ѭ5更改为:
public void onUpgrade(SQLiteDatabase db,int oldVersion,int newVersion) {
if (newVersion > oldVersion)
Log.v(“Database Upgrade”,“Database version higher than old.”);
myContext.deleteDatabase(DB_NAME);
}
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