查看今日的日期與之前的日期的差異android

Question

我必須找到今天的日期和另一個日期之間的日差。我怎樣才能找到？

我寫的代碼：

Calendar calfromDate = Calendar.getInstance(); 
calfromDate.set(m_nVYear, m_nVMonth, m_nVDay); 
long m_lDate = calfromDate.getTimeInMillis(); 
Calendar calToday = Calendar.getInstance(); 
long today = calToday.getTimeInMillis(); 
Log.d("debug", "today:" +today); 
Log.d("debug", "from date:" +m_lDate); 
int day_difference = (int)((m_lDate - today)/(24*60*60*1000)); 

Answer 1

從http://tripoverit.blogspot.com/2007/07/java-calculate-difference-between-two.html：

public static long daysBetween(Calendar startDate, Calendar endDate) { 
    Calendar date = (Calendar) startDate.clone(); 
    long daysBetween = 0; 
    while (date.before(endDate)) { 
    date.add(Calendar.DAY_OF_MONTH, 1); 
    daysBetween++; 
    } 
    return daysBetween; 
} 

Answer 2

嘗試用下面的代碼

// Creates two calendars instances 
    Calendar cal1 = Calendar.getInstance(); 
    Calendar cal2 = Calendar.getInstance(); 

    // Set the date for both of the calendar instance 
    cal1.set(2006, 12, 30); 
    cal2.set(2007, 5, 3); 

    // Get the represented date in milliseconds 
    long milis1 = cal1.getTimeInMillis(); 
    long milis2 = cal2.getTimeInMillis(); 

    // Calculate difference in milliseconds 
    long diff = milis2 - milis1; 

    // Calculate difference in seconds 
    long diffSeconds = diff/1000; 

    // Calculate difference in minutes 
    long diffMinutes = diff/(60 * 1000); 

    // Calculate difference in hours 
    long diffHours = diff/(60 * 60 * 1000); 

    // Calculate difference in days 
    long diffDays = diff/(24 * 60 * 60 * 1000); 

    System.out.println("In milliseconds: " + diff + " milliseconds."); 
    System.out.println("In seconds: " + diffSeconds + " seconds."); 
    System.out.println("In minutes: " + diffMinutes + " minutes."); 
    System.out.println("In hours: " + diffHours + " hours."); 
    System.out.println("In days: " + diffDays + " days.");