/** * Create and/or open a database that will be used for reading and writing. * Once opened successfully, the database is cached, so you can call this * method every time you need to write to the database. Make sure to call * {
@link #close}
when you no longer need it. * * <p>Errors such as bad permissions or a full disk may cause this operation * to fail, but future attempts may succeed if the problem is fixed.</p> * * @throws SQLiteException if the database cannot be opened for writing * @return a read/write database object valid until {
@link #close}
is called */ public synchronized SQLiteDatabase getWritableDatabase() {
if (mDatabase != null && mDatabase.isOpen() && !mDatabase.isReadOnly()) {
return mDatabase;
// The database is already open for business }
if (mIsInitializing) {
throw new IllegalStateException("getWritableDatabase called recursively");
}
// If we have a read-only database open, someone could be using it // (though they shouldn't), which would cause a lock to be held on // the file, and our attempts to open the database read-write would // fail waiting for the file lock. To prevent that, we acquire the // lock on the read-only database, which shuts out other users. boolean success = false;
SQLiteDatabase db = null;
if (mDatabase != null) mDatabase.lock();
try {
mIsInitializing = true;
if (mName == null) {
db = SQLiteDatabase.create(null);
}
else {
db = mContext.openOrCreateDatabase(mName, 0, mFactory);
}
int version = db.getVersion();
if (version != mNewVersion) {
db.beginTransaction();
try {
if (version == 0) {
onCreate(db);
}
else {
onUpgrade(db, version, mNewVersion);
}
db.setVersion(mNewVersion);
db.setTransactionSuccessful();
}
finally {
db.endTransaction();
}
}
onOpen(db);
success = true;
return db;
}
finally {
mIsInitializing = false;
if (success) {
if (mDatabase != null) {
try {
mDatabase.close();
}
catch (Exception e) {
}
mDatabase.unlock();
}
mDatabase = db;
}
else {
if (mDatabase != null) mDatabase.unlock();
if (db != null) db.close();
}
}
}
/** * Create and/or open a database. This will be the same object returned by * {
@link #getWritableDatabase}
unless some problem, such as a full disk, * requires the database to be opened read-only. In that case, a read-only * database object will be returned. If the problem is fixed, a future call * to {
@link #getWritableDatabase}
may succeed, in which case the read-only * database object will be closed and the read/write object will be returned * in the future. * * @throws SQLiteException if the database cannot be opened * @return a database object valid until {
@link #getWritableDatabase}
* or {
@link #close}
is called. */ public synchronized SQLiteDatabase getReadableDatabase() {
if (mDatabase != null && mDatabase.isOpen()) {
return mDatabase;
// The database is already open for business }
if (mIsInitializing) {
throw new IllegalStateException("getReadableDatabase called recursively");
}
try {
return getWritableDatabase();
}
catch (SQLiteException e) {
if (mName == null) throw e;
// Can't open a temp database read-only! Log.e(TAG, "Couldn't open " + mName + " for writing (will try read-only):", e);
}
SQLiteDatabase db = null;
try {
mIsInitializing = true;
String path = mContext.getDatabasePath(mName).getPath();
db = SQLiteDatabase.openDatabase(path, mFactory, SQLiteDatabase.OPEN_READONLY);
if (db.getVersion() != mNewVersion) {
throw new SQLiteException("Can't upgrade read-only database from version " + db.getVersion() + " to " + mNewVersion + ": " + path);
}
onOpen(db);
Log.w(TAG, "Opened " + mName + " in read-only mode");
mDatabase = db;
return mDatabase;
}
finally {
mIsInitializing = false;
if (db != null && db != mDatabase) db.close();
}
}