It seems that you have to call getReadableDatabase or getWritableDatabase before you need the data, this is because it takes time to create the database.So, you have to be aware of that.

Also, I wanted to remark that you must cursor.moveToFirst() before you do cursor.moveToNext() on sendsms.java

Please change your code like this:-

 try {

        Cursor cursor = databaseHelper.getdata();
        if (cursor != null && cursor.getCount() > 0) {
            while (cursor.moveToNext()) {

               String num = cursor.getString(0);
               String numm = cursor.getString(1);
               String nummm = cursor.getString(2);

           }
     }

   }
    catch(Exception e){
        Toast.makeText(getBaseContext(), e.getMessage(),
                Toast.LENGTH_SHORT).show();
    }

This the error

I have attached the error above after executing code below mentioned, the code given below is not full code but it targets the main code for which my question is.I am trying to send sms through a variable in which number is stored by fetching from sqlite database. So below code shows that I tried to fetch from dbhelper.java class and store in variable num in sendsms.java class but i think it is not fetching Hence i would request you to see the code and guide where i am wrong for improvement. I hope that now question is clear and sufficient description is given so please help.

sendsms.java

   try {

            Cursor cursor = databaseHelper.getdata();
            while (cursor.moveToNext())

            {

                String num = cursor.getString(0);
                String numm = cursor.getString(1);
                String nummm = cursor.getString(2);

            }

       }
        catch(Exception e){
            Toast.makeText(getBaseContext(), e.getMessage(),
                    Toast.LENGTH_SHORT).show();
        }

            public void run() {

                sms.sendTextMessage(num, null, "Help! I've met with an accident at http://maps.google.com/?q=" + String.valueOf(latitude) + "" +
                        "," + String.valueOf(longitude), null, null);

dbhelper.java

    public static final String TABLE_REGISTER = "signin";
    public static final String COL_ID = "USER_ID";
    public static final String COL_NAME = "NAME";
    public static final String COL_PHONE = "PHONE_NUMBER";
    public static final String COL_EMAIL = "EMAIL";
    public static final String COL_PASSWORD = "PASSWORD";
    public static final String COL_CONFIRM_PASSWORD = "CONFIRM_PASSWORD";

    public static final String COL_NAMEone_CON = "NAMEONE";
    public static final String COL_NUMBERone_CON = "NUMBERONE";
    public static final String COL_NAMEtwo_CON = "NAMETWO";
    public static final String COL_NUMBERtwo_CON = "NUMBERTWO";
    public static final String COL_NAMEthree_CON = "NAMETHREE";
    public static final String COL_NUMBERthree_CON = "NUMBERTHREE";

    public SQLiteDatabase db;

    @Override
    public void onCreate(SQLiteDatabase db) {
        db.execSQL("CREATE TABLE " + TABLE_REGISTER + "(" + COL_ID + " INTEGER PRIMARY KEY AUTOINCREMENT , "
                + COL_NAME + " TEXT , " + COL_PHONE + "  LONG  UNIQUE  ," + COL_EMAIL + " VARCHAR UNIQUE," + COL_PASSWORD + " VARCHAR , "
                + COL_CONFIRM_PASSWORD + " VARCHAR ," + COL_NAMEone_CON + " TEXT , "
                + COL_NUMBERone_CON + "  LONG  UNIQUE ," + COL_NAMEtwo_CON + " TEXT ," + COL_NUMBERtwo_CON + "  LONG  UNIQUE , "
                + COL_NAMEthree_CON + " TEXT ," + COL_NUMBERthree_CON + " LONG  UNIQUE " + ")");

    }

    public Cursor getdata(){
        SQLiteDatabase db = this.getWritableDatabase();

        Cursor cursor = db.rawQuery("select NUMBERONE, NUMBERTWO,NUMBERTHREE  from signin ", null);

        return cursor;
    }