Question

In my Android application, I have 3 spinners for Hour/Minute/ and PM or AM. I’d like to add 7.5 hours in that to get the needed time for the user to sleep. This android application of mine is a calculator of a user’s sleep. For example, I’d like to wake up at 7:00 AM. BY 11:15 PM you should now be sleeping. Please give me some directions on how to do this. I’m in dire need of help. Thanks. Appreciate your help.

like this:

  /**
   * Get sleeping times corresponding to a local time
   * 
   * @param wakingTime
   *            time to wake up !
   * @return list of times one should go to bed to
   */

  public static Set<Date> getSleepingTimes(Date wakingTime) {

    Set<Date> result = new TreeSet<Date>();
    Calendar calendar = Calendar.getInstance();
    calendar.setTime( wakingTime );
    calendar.add( Calendar.MINUTE, -14 );
    calendar.add( Calendar.MINUTE, -( 2 * 90 ) );
    for ( int i = 3; i <= 6; i++ ) {
      calendar.add( Calendar.MINUTE, -90 );
      result.add( calendar.getTime() );
    }
    return result;

  } // end of getSleepingTimes method

Answer 1

public static Date getSleepingTimes(Date wakingTime) {

    Calendar calendar = Calendar.getInstance();
    calendar.setTime( wakingTime );
    calendar.add(Calendar.HOUR,-7);
    calendar.add(Calendar.MINUTE,-30);

    return calendar.getTime();

}

but better not to hard code the 7.5 hours.

public static Date getSleepingTimes(Date wakingTime, int hoursToSleep, int minutesToSleep) {

    Calendar calendar = Calendar.getInstance();
    calendar.setTime( wakingTime );
    calendar.add(Calendar.HOUR,-hoursToSleep);
    calendar.add(Calendar.MINUTE,-minutesToSleep);

    return calendar.getTime();

}

use like this:

   getSleepingTime(wakingTime, 7, 30);