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I am new to the coding. I want to take input from the user and the input will be an integer value.
ex: if input is 5
I want to execute select statement where in the query will return everything in the 5th row of a table in the database.
How can i achieve this? I have copied my database to assets folder and have the following code.
Java
package com.example.c;

import java.io.IOException;

import android.os.Bundle;
import android.app.Activity;
import android.database.SQLException;
import android.view.Menu;

public class C extends Activity {

   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.c);
      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;
      }
   }

   @Override
   public boolean onCreateOptionsMenu(Menu menu) {
      // Inflate the menu; this adds items to the action bar if it is present.
      getMenuInflater().inflate(R.menu.c, menu);
      return true;
   }
}


and the DataBaseHelper class is as below
Java
package com.example.c;

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 DB_PATH = "/data/data/com.example.c/databases/";
   private static String DB_NAME = "MyDatabase";
   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.
}


For the above code, i am not able to execute any queries. The emulator shows it stopped. From the DDMS view->file explorer-> selecting the package->databases, i found the database copied but it only consists of android_metadata table. The tables in my database are not in it.
Posted
Updated 21-Sep-13 22:24pm
v3

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