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jamepaul on 09/10/11

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Own sqlite database in android

/ Published in: Java

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package com.package.name;

import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

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

public class DatabaseHelper extends SQLiteOpenHelper {
	
	private static String DB_PATH = "/data/data/com.hotel.directory/databases/";
	private static String DB_NAME = "dbname.db";
	private SQLiteDatabase db;
	private final Context myContext;
	
	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 dosen'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) {
			
		}
		
		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;
		db = SQLiteDatabase.openDatabase(myPath, null, SQLiteDatabase.OPEN_READONLY);
	}
	
	@Override
	public synchronized void close() {
		if(db != null)
			db.close();
		
		super.close();
	}

@Override
	public void onCreate(SQLiteDatabase db) {
		// TODO Auto-generated method stub
		
	}

@Override
	public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
		// TODO Auto-generated method stub
		
	}

}

URL: http://www.reigndesign.com/blog/using-your-own-sqlite-database-in-android-applications/

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