Android Open Source - hts-cycle Data Base Helper

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License

The source code is released under:
GNU General Public License
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Java Source Code

package it.uniroma2.wifionoff;
/*  w w  w .  j  a  v  a  2  s .  c o  m*/
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.content.Context;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;


public class DataBaseHelper extends SQLiteOpenHelper{
    
//The Android's default system path of your application database.
//private static String lol=Environment.getDataDirectory().toString();
private static String DB_PATH = "/data/data/it.uniroma2.wifionoff/databases/";

private static String DB_NAME = "Db.sqlite";
 
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.
 
}
Java Source Code List
