Android Open Source - Dhamaschool Database Manager

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License

The source code is released under:
Apache License
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Java Source Code

package group.ripple.dhamaschool;
/*from w w  w . ja  v a2 s.c  o m*/
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;
import android.util.Log;

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

public class DatabaseManager extends SQLiteOpenHelper {

  private static String DB_NAME = "dhamaschool.sqlite";
  public static Context mContext;
  private SQLiteDatabase db;
  private static DatabaseManager helper;

  public static synchronized DatabaseManager getInstance(Context context) {
    if (helper == null) {
      helper = new DatabaseManager(context);
    }

    return helper;
  }

  public DatabaseManager(Context context) {
    super(context, DB_NAME, null, 1);
    DatabaseManager.mContext = context;
    try {
      boolean dbexist = checkdatabase();
      if (dbexist) {
        // System.out.println("Database exists");
        opendatabase();
      } else {
        System.out.println("Database doesn't exist");
        createdatabase();
        System.out.println(" Database Copied");
        opendatabase();
      }
    } catch (Exception e) {
      // TODO: handle exception
      e.printStackTrace();
    }
  }

  public void createdatabase() throws IOException {
    boolean dbexist = checkdatabase();
    if (dbexist) {
      System.out.println(" Database exists.");
    } else {
      this.getReadableDatabase();
      try {
        System.out.println(" Database Copying");
        copydatabase();
      } catch (IOException e) {
        // throw new Error("Error copying database");
        e.printStackTrace();
      }
    }
  }

  private boolean checkdatabase() {
    boolean checkdb = false;
    try {
      String myPath = mContext.getFilesDir().getPath() + DB_NAME;
      File dbfile = new File(myPath);
      checkdb = dbfile.exists();
    } catch (SQLiteException e) {
      e.printStackTrace();
      System.out.println("Database doesn't exist");
    }

    return checkdb;
  }

  private void copydatabase() throws IOException {

    InputStream myinput = mContext.getAssets().open(DB_NAME);
    String outfilename = mContext.getFilesDir().getPath() + DB_NAME;
    System.out.println(outfilename);
    OutputStream myoutput = new FileOutputStream(outfilename);
    byte[] buffer = new byte[1024];
    int length;
    while ((length = myinput.read(buffer)) > 0) {
      myoutput.write(buffer, 0, length);
    }
    myoutput.flush();
    myoutput.close();
    myinput.close();

  }

  public void opendatabase() throws SQLException {
    // Open the database
    String mypath = mContext.getFilesDir().getPath() + DB_NAME;
    db = SQLiteDatabase.openDatabase(mypath, null,
        SQLiteDatabase.OPEN_READWRITE);
  }

  public SQLiteDatabase getDB() {
    return db;
  }

  public boolean CheckIfExist(String table, String field, String value) {
    String query = "SELECT * FROM " + table + " WHERE " + field + " = '"
        + value + "'";

    catchLog("CheckQuery ==> " + query);

    Cursor c = this.db.rawQuery(query, null);
    if (c.moveToFirst()) {
      do {
        if (c.getInt(0) != 0)
          return true;
        else
          return false;
      } while (c.moveToNext());
    } else {
      return false;
    }
  }

  public boolean CheckIfExist2(String table, String field, String value) {

    String query = "SELECT * FROM " + table + " WHERE " + field + " = '"
        + value + "'";

    catchLog("CheckQuery ==> " + query);

    Cursor c = this.db.rawQuery(query, null);
    if (c.moveToFirst()) {
      do {
        if (c.getString(0).equalsIgnoreCase(value))
          return true;
        else
          return false;
      } while (c.moveToNext());
    } else {
      return false;
    }
  }

  public boolean CheckIfExist(String table, String firstField,
      String firstValue, String secondField, String secondValue) {

    String query = "SELECT * FROM " + table + " WHERE " + firstField
        + " = '" + firstValue + "'" + " AND " + secondField + " = '"
        + secondValue + "'";

    catchLog("CheckQuery ==> " + query);

    Cursor c = this.db.rawQuery(query, null);
    if (c.moveToFirst()) {
      do {
        if (c.getString(1).equalsIgnoreCase(firstValue)
            && c.getString(2).equalsIgnoreCase(secondValue))
          return true;
        else
          return false;
      } while (c.moveToNext());
    } else {
      return false;
    }
  }

  public boolean CheckIfExist(String table, String field, int value) {
    return CheckIfExist(table, field, value + "");
  }

  public void deleteDatabase() throws IOException {
    try {
      String myPath = mContext.getFilesDir().getPath() + DB_NAME;
      File dbfile = new File(myPath);
      if (dbfile.exists())
        dbfile.delete();
    } catch (SQLException e) {

    }
  }

  private void catchLog(String log) {
    Log.i(getClass().getSimpleName(), log);
  }

  public synchronized void close() {
    if (db != null) {
      db.close();
    }
    super.close();
  }

  @Override
  public void onCreate(SQLiteDatabase arg0) {
    // TODO Auto-generated method stub

  }

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

  }

}
Java Source Code List
