我正在尝试同时使用两个数据库文件，我认为这是可能的，但我似乎遇到了一个只有最后一个打开的问题可供使用的问题。
如果我的代码安排如下，则有效：
private void populateTabs(int TabShown) {
// Get specific setup info from database into cursor
setupDBHelper = new DBAdapter(this);
setupDBHelper.open(DBAdapter.MAIN_DATABASE_NAME, DBAdapter.MAIN_DATABASE_VERSION);
setupCursor = setupDBHelper.fetchSetup(RowId);
this.startManagingCursor(setupCursor);
setupCursor.moveToFirst();
offsetDBHelper = new DBAdapter(this);
offsetDBHelper.open(DBAdapter.OFFSET_DATABASE_NAME, DBAdapter.OFFSET_DATABASE_VERSION);
offsetCursor = offsetDBHelper.fetchOffset(setupCursor.getString(setupCursor
.getColumnIndex(DBAdapter.SETUP_PART)));
this.startManagingCursor(offsetCursor);
offsetCursor.moveToFirst();
}
但是，如果我按如下方式重新排列代码，当它尝试运行fetchSetup（）时，我得到一个“没有这样的表：xxxx”，这表明它正在尝试使用wrogn db，即使我已指向它正确的（或者在我看来）：
private void populateTabs(int TabShown) {
// Get specific setup info from database into cursor
setupDBHelper = new DBAdapter(this);
setupDBHelper.open(DBAdapter.MAIN_DATABASE_NAME, DBAdapter.MAIN_DATABASE_VERSION);
offsetDBHelper = new DBAdapter(this);
offsetDBHelper.open(DBAdapter.OFFSET_DATABASE_NAME, DBAdapter.OFFSET_DATABASE_VERSION);
setupCursor = setupDBHelper.fetchSetup(RowId);
this.startManagingCursor(setupCursor);
setupCursor.moveToFirst();
offsetCursor = offsetDBHelper.fetchOffset(setupCursor.getString(setupCursor
.getColumnIndex(DBAdapter.SETUP_PART)));
this.startManagingCursor(offsetCursor);
offsetCursor.moveToFirst();
}
没什么大不了的，除了我有几个其他方法专门引用一个或另一个数据库，我不会控制这些方法的使用顺序，也不希望每次都打开和关闭数据库。我宁愿打开一次，完成后关闭。
我错过了一些明显的东西吗？有可能吗？
如果您需要我的代码的其他部分让我知道，我会很乐意发布它。
修改
我的DBAdapter的相关位：
public class DBAdapter {
// DB info
public static final String MAIN_DATABASE_NAME = "Bowers";
public static final String OFFSET_DATABASE_NAME = "BowersOffset";
public static final String NOTES_DATABASE_NAME = "Notes";
public static final String GMCODES_DATABASE_NAME = "GMCodes";
public static final int MAIN_DATABASE_VERSION = 1;
public static final int OFFSET_DATABASE_VERSION = 1;
public static final int NOTES_DATABASE_VERSION = 1;
public static final int GMCODES_DATABASE_VERSION = 1;
public static String MAIN_DB_PATH = "/data/data/cdc.workshopapps.BowersMfgHelper/databases/";
// database control
private DatabaseHelper mDbHelper;
private static SQLiteDatabase mDb;
private static Context mCtx;
private static class DatabaseHelper extends SQLiteOpenHelper {
DatabaseHelper(Context context, String dbname, int dbversion) {
super(context, dbname, null, dbversion);
if (checkDataBase(dbname)) {
openDataBase(dbname);
} else {
try {
this.getReadableDatabase();
copyDataBase(dbname);
this.close();
openDataBase(dbname);
} catch (IOException e) {
throw new Error("Error copying database");
}
Toast.makeText(context,
"Initial " + dbname + " database has been created",
Toast.LENGTH_LONG).show();
}
}
@Override
public void onCreate(SQLiteDatabase db) {
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
public DBAdapter(Context ctx) {
DBAdapter.mCtx = ctx;
}
public DBAdapter open(String dbname, int dbversion) throws SQLException {
mDbHelper = new DatabaseHelper(mCtx, dbname, dbversion);
mDb = mDbHelper.getWritableDatabase();
return this;
}
public void close() {
mDbHelper.close();
}
private static void copyDataBase(String dbname) throws IOException {
InputStream myInput = mCtx.getAssets().open(dbname);
String outFileName = MAIN_DB_PATH + dbname;
OutputStream myOutput = new FileOutputStream(outFileName);
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
myOutput.flush();
myOutput.close();
myInput.close();
}
private static boolean checkDataBase(String dbname) {
SQLiteDatabase checkDB = null;
boolean exist = false;
try {
String db = MAIN_DB_PATH + dbname;
checkDB = SQLiteDatabase.openDatabase(db, null,
SQLiteDatabase.OPEN_READONLY);
} catch (SQLiteException e) {
Log.v("db log", "database does't exist");
}
if (checkDB != null) {
exist = true;
checkDB.close();
}
return exist;
}
public static void openDataBase(String dbname) throws SQLException {
String dbPath = MAIN_DB_PATH + dbname;
mDb = SQLiteDatabase.openDatabase(dbPath, null,
SQLiteDatabase.OPEN_READWRITE);
}
// public Cursor fetchOffset(String part) throws SQLException {
// Cursor mCursor = mDb.query(true, OFFSET_TABLE, new String[] {
// OFFSET_ROWID, OFFSET_PART, SETUP_D1, SETUP_D2, SETUP_D3,
// SETUP_D4, SETUP_D5, SETUP_D6, SETUP_D7, SETUP_D8, SETUP_D9,
// SETUP_D10, SETUP_D11, SETUP_D12, SETUP_D13, SETUP_D14,
// SETUP_D15, SETUP_D16, SETUP_D17, SETUP_D18, SETUP_D19,
// SETUP_D20, SETUP_G54, SETUP_G55, SETUP_G56, SETUP_G57,
// SETUP_G58, SETUP_G59, SETUP_G110, SETUP_G111, SETUP_G112,
// SETUP_G113, SETUP_G114, SETUP_G115, SETUP_G116, SETUP_G117,
// SETUP_G118, SETUP_G119, SETUP_G120, SETUP_G121, SETUP_G122,
// SETUP_G123 }, OFFSET_PART + "= '" + part + "'", null, null,
// null, null, null);
// if (mCursor != null) {
// mCursor.moveToFirst();
// }
// return mCursor;
// }
public Cursor fetchSetup(Long rowId) throws SQLException {
Cursor mCursor = mDb.query(true, SETUP_TABLE, new String[] {
SETUP_ROWID, SETUP_PART, SETUP_PGM1, SETUP_PGM2, SETUP_PGM3,
SETUP_T1, SETUP_T2, SETUP_T3, SETUP_T4, SETUP_T5, SETUP_T6,
SETUP_T7, SETUP_T8, SETUP_T9, SETUP_T10, SETUP_T11, SETUP_T12,
SETUP_T13, SETUP_T14, SETUP_T15, SETUP_T16, SETUP_T17,
SETUP_T18, SETUP_T19, SETUP_T20, SETUP_KIT, SETUP_FIXTURE1,
SETUP_FIXTURE2, SETUP_FIXTURELOC, SETUP_VISE, SETUP_JAWS,
SETUP_JAWLOC, SETUP_NOTES, SETUP_MISC1, SETUP_MISC2,
SETUP_MISC3, SETUP_D1, SETUP_D2, SETUP_D3, SETUP_D4, SETUP_D5,
SETUP_D6, SETUP_D7, SETUP_D8, SETUP_D9, SETUP_D10, SETUP_D11,
SETUP_D12, SETUP_D13, SETUP_D14, SETUP_D15, SETUP_D16,
SETUP_D17, SETUP_D18, SETUP_D19, SETUP_D20, SETUP_G54,
SETUP_G55, SETUP_G56, SETUP_G57, SETUP_G58, SETUP_G59,
SETUP_G110, SETUP_G111, SETUP_G112, SETUP_G113, SETUP_G114,
SETUP_G115, SETUP_G116, SETUP_G117, SETUP_G118, SETUP_G119,
SETUP_G120, SETUP_G121, SETUP_G122, SETUP_G123 }, TOOL_ROWID
+ "=" + rowId, null, null, null, null, null);
if (mCursor != null) {
mCursor.moveToFirst();
}
return mCursor;
}
}