android - I am trying to set alarm on specific time using alarm manager but alarm initiated instantly?

This is my onclick() function.this will set target alarm

      SA=(Button)findViewById(R.id.button1);
      SA.setOnClickListener(new OnClickListener() {

        @SuppressWarnings("deprecation")
        @Override
            public void onClick(View v) {

                showDialog(id);


            }
        });

    }
        @Override
        protected Dialog onCreateDialog(int id1) {
        switch (id1) {

        case id:
            // set time picker as current time

            return new TimePickerDialog(this, 
                                         timePickerListener, hour, min,false);
        }
        return null;
    }

        private TimePickerDialog.OnTimeSetListener timePickerListener = 

            new TimePickerDialog.OnTimeSetListener() {
        public void onTimeSet(TimePicker view, int selectedHour,
                int selectedMinute) {
            Calendar calnow=Calendar.getInstance();
            calnow.setTimeInMillis(System.currentTimeMillis());
            calnow.set(Calendar.HOUR_OF_DAY,selectedHour);
            calnow.set(Calendar.MINUTE,selectedMinute);
            calnow.set(Calendar.SECOND, 0);
             Intent intent=new Intent(getBaseContext(),alarm.class); 
            PendingIntent pendingintent= PendingIntent.getBroadcast(getBaseContext(),0,       intent, 0);

             AlarmManager alarmManager =     (AlarmManager)getSystemService(Context.ALARM_SERVICE);

              alarmManager.set(AlarmManager.RTC_WAKEUP,  calnow.getTimeInMillis(),pendingintent);
              Toast.makeText(getBaseContext(), "alarm set", Toast.LENGTH_SHORT).show();

        }
    };

    public void onReceive(Context arg0, Intent arg1) {
         AlarmManager mgr = (AlarmManager)arg0.getSystemService(Context.ALARM_SERVICE);

            Toast.makeText(arg0,"Alarm Started.....", Toast.LENGTH_LONG).show();

Here problem is that I get both toasts "alarm set" and"alarm started" as soon as I click button to set alarm before reaching target alarm.