Add events to this Calender

I am developing a program. It has a calender. When the user presses on the date the event shows up.
Then I want the application to send a notifcation to the user whenever an event is about to happen.
The calendar I'm working with is from this site calendar example
package com.examples;    

import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import java.util.HashMap;
import java.util.List;
import java.util.Locale;

import android.app.Activity;
import android.content.Context;
import android.graphics.Color;
import android.os.Bundle;
import android.text.format.DateFormat;
import android.util.Log;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.view.View.OnClickListener;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.GridView;
import android.widget.ImageView;
import android.widget.TextView;

public class SimpleCalendarViewActivity extends Activity implements OnClickListener
    {
        private static final String tag = "SimpleCalendarViewActivity";

        private ImageView calendarToJournalButton;
    private Button selectedDayMonthYearButton;
    private Button currentMonth;
    private ImageView prevMonth;
    private ImageView nextMonth;
    private GridView calendarView;
    private GridCellAdapter adapter;
    private Calendar _calendar;
    private int month, year;
    private final DateFormat dateFormatter = new DateFormat();
    private static final String dateTemplate = "MMMM yyyy";

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState)
        {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.simple_calendar_view);

            _calendar = Calendar.getInstance(Locale.getDefault());
            month = _calendar.get(Calendar.MONTH) + 1;
            year = _calendar.get(Calendar.YEAR);
            Log.d(tag, "Calendar Instance:= " + "Month: " + month + " " + "Year: " + year);

            selectedDayMonthYearButton = (Button) this.findViewById(R.id.selectedDayMonthYear);
            selectedDayMonthYearButton.setText("Selected: ");

            prevMonth = (ImageView) this.findViewById(R.id.prevMonth);
            prevMonth.setOnClickListener(this);

            currentMonth = (Button) this.findViewById(R.id.currentMonth);
            currentMonth.setText(dateFormatter.format(dateTemplate, _calendar.getTime()));

            nextMonth = (ImageView) this.findViewById(R.id.nextMonth);
            nextMonth.setOnClickListener(this);

            calendarView = (GridView) this.findViewById(R.id.calendar);

            // Initialised
            adapter = new GridCellAdapter(getApplicationContext(), R.id.calendar_day_gridcell, month, year);
            adapter.notifyDataSetChanged();
            calendarView.setAdapter(adapter);
        }

    /**
     * 
     * @param month
     * @param year
     */
    private void setGridCellAdapterToDate(int month, int year)
        {
            adapter = new GridCellAdapter(getApplicationContext(), R.id.calendar_day_gridcell, month, year);
            _calendar.set(year, month - 1, _calendar.get(Calendar.DAY_OF_MONTH));
            currentMonth.setText(dateFormatter.format(dateTemplate, _calendar.getTime()));
            adapter.notifyDataSetChanged();
            calendarView.setAdapter(adapter);
        }

    @Override
    public void onClick(View v)
        {
            if (v == prevMonth)
                {
                    if (month <= 1)
                        {
                            month = 11;
                            year--;
                        }
                    else
                        {
                            month--;
                        }
                    Log.d(tag, "Setting Prev Month in GridCellAdapter: " + "Month: " + month + " Year: " + year);
                    setGridCellAdapterToDate(month, year);
                }
            if (v == nextMonth)
                {
                    if (month > 11)
                        {
                            month = 1;
                            year++;
                        }
                    else
                        {
                            month++;
                        }
                    Log.d(tag, "Setting Next Month in GridCellAdapter: " + "Month: " + month + " Year: " + year);
                    setGridCellAdapterToDate(month, year);
                }

        }

    @Override
    public void onDestroy()
        {
            Log.d(tag, "Destroying View ...");
            super.onDestroy();
        }

    // ///////////////////////////////////////////////////////////////////////////////////////
    // Inner Class
    public class GridCellAdapter extends BaseAdapter implements OnClickListener
        {
            private static final String tag = "GridCellAdapter";
            private final Context _context;

            private final List<String> list;
            private static final int DAY_OFFSET = 1;
            private final String[] weekdays = new String[]{"Sun", "Mon", "Tue", "Wed", "Thu", "Fri", "Sat"};
            private final String[] months = {"January", "February", "March", "April", "May", "June", "July", "August", "September", "October", "November", "December"};
            private final int[] daysOfMonth = {31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31};
            private final int month, year;
            private int daysInMonth, prevMonthDays;
            private int currentDayOfMonth;
            private int currentWeekDay;
            private Button gridcell;
            private TextView num_events_per_day;
            private final HashMap eventsPerMonthMap;
            private final SimpleDateFormat dateFormatter = new SimpleDateFormat("dd-MMM-yyyy");

            // Days in Current Month
            public GridCellAdapter(Context context, int textViewResourceId, int month, int year)
                {
                    super();
                    this._context = context;
                    this.list = new ArrayList<String>();
                    this.month = month;
                    this.year = year;

                    Log.d(tag, "==> Passed in Date FOR Month: " + month + " " + "Year: " + year);
                    Calendar calendar = Calendar.getInstance();
                    setCurrentDayOfMonth(calendar.get(Calendar.DAY_OF_MONTH));
                    setCurrentWeekDay(calendar.get(Calendar.DAY_OF_WEEK));
                    Log.d(tag, "New Calendar:= " + calendar.getTime().toString());
                    Log.d(tag, "CurrentDayOfWeek :" + getCurrentWeekDay());
                    Log.d(tag, "CurrentDayOfMonth :" + getCurrentDayOfMonth());

                    // Print Month
                    printMonth(month, year);

                    // Find Number of Events
                    eventsPerMonthMap = findNumberOfEventsPerMonth(year, month);
                }
            private String getMonthAsString(int i)
                {
                    return months[i];
                }

            private String getWeekDayAsString(int i)
                {
                    return weekdays[i];
                }

            private int getNumberOfDaysOfMonth(int i)
                {
                    return daysOfMonth[i];
                }

            public String getItem(int position)
                {
                    return list.get(position);
                }

            @Override
            public int getCount()
                {
                    return list.size();
                }

            /**
             * Prints Month
             * 
             * @param mm
             * @param yy
             */
            private void printMonth(int mm, int yy)
                {
                    Log.d(tag, "==> printMonth: mm: " + mm + " " + "yy: " + yy);
                    // The number of days to leave blank at
                    // the start of this month.
                    int trailingSpaces = 0;
                    int leadSpaces = 0;
                    int daysInPrevMonth = 0;
                    int prevMonth = 0;
                    int prevYear = 0;
                    int nextMonth = 0;
                    int nextYear = 0;

                    int currentMonth = mm - 1;
                    String currentMonthName = getMonthAsString(currentMonth);
                    daysInMonth = getNumberOfDaysOfMonth(currentMonth);

                    Log.d(tag, "Current Month: " + " " + currentMonthName + " having " + daysInMonth + " days.");

                    // Gregorian Calendar : MINUS 1, set to FIRST OF MONTH
                    GregorianCalendar cal = new GregorianCalendar(yy, currentMonth, 1);
                    Log.d(tag, "Gregorian Calendar:= " + cal.getTime().toString());

                    if (currentMonth == 11)
                        {
                            prevMonth = currentMonth - 1;
                            daysInPrevMonth = getNumberOfDaysOfMonth(prevMonth);
                            nextMonth = 0;
                            prevYear = yy;
                            nextYear = yy + 1;
                            Log.d(tag, "*->PrevYear: " + prevYear + " PrevMonth:" + prevMonth + " NextMonth: " + nextMonth + " NextYear: " + nextYear);
                        }
                    else if (currentMonth == 0)
                        {
                            prevMonth = 11;
                            prevYear = yy - 1;
                            nextYear = yy;
                            daysInPrevMonth = getNumberOfDaysOfMonth(prevMonth);
                            nextMonth = 1;
                            Log.d(tag, "**--> PrevYear: " + prevYear + " PrevMonth:" + prevMonth + " NextMonth: " + nextMonth + " NextYear: " + nextYear);
                        }
                    else
                        {
                            prevMonth = currentMonth - 1;
                            nextMonth = currentMonth + 1;
                            nextYear = yy;
                            prevYear = yy;
                            daysInPrevMonth = getNumberOfDaysOfMonth(prevMonth);
                            Log.d(tag, "***---> PrevYear: " + prevYear + " PrevMonth:" + prevMonth + " NextMonth: " + nextMonth + " NextYear: " + nextYear);
                        }

                    // Compute how much to leave before before the first day of the
                    // month.
                    // getDay() returns 0 for Sunday.
                    int currentWeekDay = cal.get(Calendar.DAY_OF_WEEK) - 1;
                    trailingSpaces = currentWeekDay;

                    Log.d(tag, "Week Day:" + currentWeekDay + " is " + getWeekDayAsString(currentWeekDay));
                    Log.d(tag, "No. Trailing space to Add: " + trailingSpaces);
                    Log.d(tag, "No. of Days in Previous Month: " + daysInPrevMonth);

                    if (cal.isLeapYear(cal.get(Calendar.YEAR)) && mm == 2)
                        {
                            ++daysInMonth;
                        }

                    // Trailing Month days
                    for (int i = 0; i < trailingSpaces; i++)
                        {
                            Log.d(tag, "PREV MONTH:= " + prevMonth + " => " + getMonthAsString(prevMonth) + " " + String.valueOf((daysInPrevMonth - trailingSpaces + DAY_OFFSET) + i));
                            list.add(String.valueOf((daysInPrevMonth - trailingSpaces + /*DAY_OFFSET)*/ 1) + i) + "-GREY" + "-" + getMonthAsString(prevMonth) + "-" + prevYear);
                        }

                    // Current Month Days
                    for (int i = 1; i <= daysInMonth; i++)
                        {
                            Log.d(currentMonthName, String.valueOf(i) + " " + getMonthAsString(currentMonth) + " " + yy);
                            if (i == getCurrentDayOfMonth())
                                {
                                    list.add(String.valueOf(i) + "-BLUE" + "-" + getMonthAsString(currentMonth) + "-" + yy);
                                }
                            else
                                {
                                    list.add(String.valueOf(i) + "-WHITE" + "-" + getMonthAsString(currentMonth) + "-" + yy);
                                }
                        }

                    // Leading Month days
                    for (int i = 0; i < list.size() % 7; i++)
                        {
                            Log.d(tag, "NEXT MONTH:= " + getMonthAsString(nextMonth));
                            list.add(String.valueOf(i + 1) + "-GREY" + "-" + getMonthAsString(nextMonth) + "-" + nextYear);
                        }
                }

            /**
             * NOTE: YOU NEED TO IMPLEMENT THIS PART Given the YEAR, MONTH, retrieve
             * ALL entries from a SQLite database for that month. Iterate over the
             * List of All entries, and get the dateCreated, which is converted into
             * day.
             * 
             * @param year
             * @param month
             * @return
             */
            private HashMap findNumberOfEventsPerMonth(int year, int month)
                {
                    HashMap map = new HashMap<String, Integer>();
                    // DateFormat dateFormatter2 = new DateFormat();
                    //                      
                    // String day = dateFormatter2.format("dd", dateCreated).toString();
                    //
                    // if (map.containsKey(day))
                    // {
                    // Integer val = (Integer) map.get(day) + 1;
                    // map.put(day, val);
                    // }
                    // else
                    // {
                    // map.put(day, 1);
                    // }
                    return map;
                }

            @Override
            public long getItemId(int position)
                {
                    return position;
                }

            @Override
            public View getView(int position, View convertView, ViewGroup parent)
                {
                    View row = convertView;
                    if (row == null)
                        {
                            LayoutInflater inflater = (LayoutInflater) _context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
                            row = inflater.inflate(R.layout.calendar_day_gridcell, parent, false);
                        }

                    // Get a reference to the Day gridcell
                    gridcell = (Button) row.findViewById(R.id.calendar_day_gridcell);
                    gridcell.setOnClickListener(this);

                    // ACCOUNT FOR SPACING

                    Log.d(tag, "Current Day: " + getCurrentDayOfMonth());
                    String[] day_color = list.get(position).split("-");
                    String theday = day_color[0];
                    String themonth = day_color[2];
                    String theyear = day_color[3];
                    if ((!eventsPerMonthMap.isEmpty()) && (eventsPerMonthMap != null))
                        {
                            if (eventsPerMonthMap.containsKey(theday))
                                {
                                    num_events_per_day = (TextView) row.findViewById(R.id.num_events_per_day);
                                    Integer numEvents = (Integer) eventsPerMonthMap.get(theday);
                                    num_events_per_day.setText(numEvents.toString());
                                }
                        }

                    // Set the Day GridCell
                    gridcell.setText(theday);
                    gridcell.setTag(theday + "-" + themonth + "-" + theyear);
                    Log.d(tag, "Setting GridCell " + theday + "-" + themonth + "-" + theyear);

                    if (day_color[1].equals("GREY"))
                        {
                            gridcell.setTextColor(Color.LTGRAY);
                        }
                    if (day_color[1].equals("WHITE"))
                        {
                            gridcell.setTextColor(Color.WHITE);
                        }
                    if (day_color[1].equals("BLUE"))
                        {
                            gridcell.setTextColor(getResources().getColor(R.color.static_text_color));
                        }
                    return row;
                }
            @Override
            public void onClick(View view)
                {
                    String date_month_year = (String) view.getTag();
                    selectedDayMonthYearButton.setText("Selected: " + date_month_year);

                    try
                        {
                            Date parsedDate = dateFormatter.parse(date_month_year);
                            Log.d(tag, "Parsed Date: " + parsedDate.toString());

                        }
                    catch (ParseException e)
                        {
                            e.printStackTrace();
                        }
                }

            public int getCurrentDayOfMonth()
                {
                    return currentDayOfMonth;
                }

            private void setCurrentDayOfMonth(int currentDayOfMonth)
                {
                    this.currentDayOfMonth = currentDayOfMonth;
                }
            public void setCurrentWeekDay(int currentWeekDay)
                {
                    this.currentWeekDay = currentWeekDay;
                }
            public int getCurrentWeekDay()
                {
                    return currentWeekDay;
                }
        }
}
Can anyone help me to add the event and how to send a notification to the user?
I think you are confusing with Google Calendar and the Calendar what you have created. Actually there is no default calendar app for android. The user can get a google calendar from net and he can configure that Calendar with his mail ID. And if you have to create any events or so, you should access this calendar in order to do so. Before you start working on it, check whether you have a google calendar installed. If you are using an emulator I would suggest you to go for a real device.
And refer to the below link. This might help.
How to set a reminder in Android?