Android Open Source - digitalcampus D A O Helper

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License

The source code is released under:

MIT License

Java Source Code

package com.llenguatges.digitalcampus.database;
/*  w  ww . j a  va2 s.co m*/
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

import android.content.Context;
import android.database.DatabaseErrorHandler;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteException;
import android.database.sqlite.SQLiteOpenHelper;

public class DAOHelper extends SQLiteOpenHelper {
  
  private static String DATABASE_NAME = "digitalcampus.s3db";
  private Context myContext;
  public String db_path;
  protected SQLiteDatabase db;
  
  /**
   * Constructor
   * @param context
   */
  public DAOHelper(Context context) { 
     super(context, DATABASE_NAME, null, 1); 
     this.myContext = context;
     this.db_path = this.myContext.getDatabasePath(DATABASE_NAME).getPath();
  }

  /**
   * Constructor
   * @param context
   * @param name
   * @param factory
   * @param version
   */
  public DAOHelper(Context context, String name, CursorFactory factory, int version) {
    super(context, name, factory, version);
  }

  /**
   * Constructor
   * @param context
   * @param name
   * @param factory
   * @param version
   * @param errorHandler
   */
  public DAOHelper(Context context, String name, CursorFactory factory, int version, DatabaseErrorHandler errorHandler) {
    super(context, name, factory, version, errorHandler);
  }

  /**
   * 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.
   */
  public 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.
   */
  public void onUpgrade(SQLiteDatabase arg0, int arg1, int arg2) {
  }
  
  /**
     * 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 transferring byte stream.
     */
  public void copyDataBase() throws IOException { 
    synchronized (this) { 
      db = getReadableDatabase();
      // Open data base as the input stream
      InputStream myInput = this.myContext.getAssets().open(DATABASE_NAME); 
      // Path to the just created empty data base
      String outFileName = this.db_path;
      // Open the empty data baseas the output stream 
      OutputStream myOutput = new FileOutputStream(outFileName); 
      // Transfer bytes from the input file to the output file 
      byte[] buffer = new byte[1024];
      int length; 
      while ((length = myInput.read(buffer)) > 0) { 
        myOutput.write(buffer, 0, length); 
      } 
      myOutput.flush(); 
      myOutput.close(); 
      myInput.close(); 
    } 
  }
  
  /**
   * Get readable database's instance.
   */
  public void openReadableDB(){
    this.db = getReadableDatabase(); 
  }
  
  /**
   * Get writable database's instance.
   */
  public void openWritableDB(){
    this.db = getWritableDatabase(); 
  }
  
  /**
   * Close any open database object.
   */
  public void closeDB(){
    if (this.db != null) this.db.close(); 
    super.close();
  }
  
  /**
   * Check if database exists. 
   * @return checkDB
   */
  public boolean checkDataBase(){
      SQLiteDatabase checkDB = null;
      try{
          checkDB = SQLiteDatabase.openDatabase(db_path, null, SQLiteDatabase.OPEN_READONLY); 
      }catch(SQLiteException e){
      }catch(Exception e){
      }
      if(checkDB != null){
          checkDB.close();
      }
      return checkDB != null ? true : false;
  }

}

Java Source Code List

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