import
java.io.File;
import
android.content.Context;
import
android.database.sqlite.SQLiteDatabase;
import
android.database.sqlite.SQLiteException;
import
android.database.sqlite.SQLiteDatabase.CursorFactory;
import
android.os.Environment;
import
android.util.Log;
/**
* A helper class to manage database creation and version management.
* You create a subclass implementing {@link #onCreate}, {@link #onUpgrade} and
* optionally {@link #onOpen}, and this class takes care of opening the database
* if it exists, creating it if it does not, and upgrading it as necessary.
* Transactions are used to make sure the database is always in a sensible state.
* <p>For an example, see the NotePadProvider class in the NotePad sample application,
* in the <em>samples/</em> directory of the SDK.</p>
*/
public
abstract
class
SDSQLiteOpenHelper {
private
static
final
String TAG = SDSQLiteOpenHelper.
class
.getSimpleName();
public
static
String sdcardpath;
private
final
Context mContext;
private
final
String mName;
private
final
CursorFactory mFactory;
private
final
int
mNewVersion;
private
SQLiteDatabase mDatabase =
null
;
private
boolean
mIsInitializing =
false
;
/**
* Create a helper object to create, open, and/or manage a database.
* The database is not actually created or opened until one of
* {@link #getWritableDatabase} or {@link #getReadableDatabase} is called.
*
* @param context to use to open or create the database
* @param name of the database file, or null for an in-memory database
* @param factory to use for creating cursor objects, or null for the default
* @param version number of the database (starting at 1); if the database is older,
* {@link #onUpgrade} will be used to upgrade the database
*/
public
SDSQLiteOpenHelper(Context context, String name, CursorFactory factory,
int
version) {
if
(version <
1
)
throw
new
IllegalArgumentException(
"Version must be >= 1, was "
+ version);
mContext = context;
mName = name;
mFactory = factory;
mNewVersion = version;
}
/**
* 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;
}
if
(mIsInitializing) {
throw
new
IllegalStateException(
"getWritableDatabase called recursively"
);
}
boolean
success =
false
;
SQLiteDatabase db =
null
;
try
{
mIsInitializing =
true
;
if
(mName ==
null
) {
db = SQLiteDatabase.create(
null
);
}
else
{
String path = getDatabasePath(mName).getPath();
db = SQLiteDatabase.openOrCreateDatabase(path,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 = db;
}
else
{
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;
}
if
(mIsInitializing) {
throw
new
IllegalStateException(
"getReadableDatabase called recursively"
);
}
try
{
return
getWritableDatabase();
}
catch
(SQLiteException e) {
if
(mName ==
null
)
throw
e;
Log.e(TAG,
"Couldn't open "
+ mName +
" for writing (will try read-only):"
, e);
}
SQLiteDatabase db =
null
;
try
{
mIsInitializing =
true
;
String path = getDatabasePath(mName).getPath();
db = SQLiteDatabase.openDatabase(path, mFactory, SQLiteDatabase.OPEN_READWRITE);
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();
}
}
/**
* Close any open database object.
*/
public
synchronized
void
close() {
if
(mIsInitializing)
throw
new
IllegalStateException(
"Closed during initialization"
);
if
(mDatabase !=
null
&& mDatabase.isOpen()) {
mDatabase.close();
mDatabase =
null
;
}
}
public
File getDatabasePath(String name)
{
if
(
this
.ExistSDCard()){
sdcardpath = Environment.getExternalStorageDirectory().getPath()+
"/"
;
}
return
new
File(sdcardpath+ name);
}
/**
* Called when the database is created for the first time. This is where the
* creation of tables and the initial population of the tables should happen.
*
* @param db The database.
*/
public
abstract
void
onCreate(SQLiteDatabase db);
/**
* Called when the database needs to be upgraded. The implementation
* should use this method to drop tables, add tables, or do anything else it
* needs to upgrade to the new schema version.
*
* <p>The SQLite ALTER TABLE documentation can be found
* <a href="http://sqlite.org/lang_altertable.html">here</a>. If you add new columns
* you can use ALTER TABLE to insert them into a live table. If you rename or remove columns
* you can use ALTER TABLE to rename the old table, then create the new table and then
* populate the new table with the contents of the old table.
*
* @param db The database.
* @param oldVersion The old database version.
* @param newVersion The new database version.
*/
public
abstract
void
onUpgrade(SQLiteDatabase db,
int
oldVersion,
int
newVersion);
/**
* Called when the database has been opened.
* Override method should check {@link SQLiteDatabase#isReadOnly} before
* updating the database.
*
* @param db The database.
*/
public
void
onOpen(SQLiteDatabase db) {}
private
boolean
ExistSDCard() {
Log.d(
"Exitsdcard"
,String.valueOf(android.os.Environment.getExternalStorageState().equals(
android.os.Environment.MEDIA_MOUNTED)));
if
(android.os.Environment.getExternalStorageState().equals(
android.os.Environment.MEDIA_MOUNTED)) {
return
true
;
}
else
return
false
;
}
}
