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Copying SQLite database
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public class DataBaseHelper extends SQLiteOpenHelper{ | |
//The Android's default system path of your application database. | |
private static String DB_PATH = "/data/data/YOUR_PACKAGE/databases/"; | |
private static String DB_NAME = "myDBName"; | |
private SQLiteDatabase myDataBase; | |
private final Context myContext; | |
/** | |
* Constructor | |
* Takes and keeps a reference of the passed context in order to access to the application assets and resources. | |
* @param context | |
*/ | |
public DataBaseHelper(Context context) { | |
super(context, DB_NAME, null, 1); | |
this.myContext = context; | |
} | |
/** | |
* Creates a empty database on the system and rewrites it with your own database. | |
* */ | |
public void createDataBase() throws IOException{ | |
boolean dbExist = checkDataBase(); | |
if(dbExist){ | |
//do nothing - database already exist | |
}else{ | |
//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"); | |
} | |
} | |
} | |
/** | |
* Check if the database already exist to avoid re-copying the file each time you open the application. | |
* @return true if it exists, false if it doesn't | |
*/ | |
private boolean checkDataBase(){ | |
SQLiteDatabase checkDB = null; | |
try{ | |
String myPath = DB_PATH + DB_NAME; | |
checkDB = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY); | |
}catch(SQLiteException e){ | |
//database does't exist yet. | |
} | |
if(checkDB != null){ | |
checkDB.close(); | |
} | |
return checkDB != null ? true : false; | |
} | |
/** | |
* Copies your database from your local assets-folder to the just created empty database in the | |
* system folder, from where it can be accessed and handled. | |
* This is done by transfering bytestream. | |
* */ | |
private void copyDataBase() throws IOException{ | |
//Open your local db as the input stream | |
InputStream myInput = myContext.getAssets().open(DB_NAME); | |
// Path to the just created empty db | |
String outFileName = DB_PATH + DB_NAME; | |
//Open the empty db as the output stream | |
OutputStream myOutput = new FileOutputStream(outFileName); | |
//transfer bytes from the inputfile to the outputfile | |
byte[] buffer = new byte[1024]; | |
int length; | |
while ((length = myInput.read(buffer))>0){ | |
myOutput.write(buffer, 0, length); | |
} | |
//Close the streams | |
myOutput.flush(); | |
myOutput.close(); | |
myInput.close(); | |
} | |
public void openDataBase() throws SQLException{ | |
//Open the database | |
String myPath = DB_PATH + DB_NAME; | |
myDataBase = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY); | |
} | |
@Override | |
public synchronized void close() { | |
if(myDataBase != null) | |
myDataBase.close(); | |
super.close(); | |
} | |
@Override | |
public void onCreate(SQLiteDatabase db) { | |
} | |
@Override | |
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) { | |
} | |
// Add your public helper methods to access and get content from the database. | |
// You could return cursors by doing "return myDataBase.query(....)" so it'd be easy | |
// to you to create adapters for your views. | |
} |
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... | |
DataBaseHelper myDbHelper = new DataBaseHelper(); | |
myDbHelper = new DataBaseHelper(this); | |
try { | |
myDbHelper.createDataBase(); | |
} catch (IOException ioe) { | |
throw new Error("Unable to create database"); | |
} | |
try { | |
myDbHelper.openDataBase(); | |
}catch(SQLException sqle){ | |
throw sqle; | |
} | |
... |
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