Get the remaining time between two Date dates on Android

First you have to get the difference in milliseconds:

long diff = date1.getTime() - date2.getTime();

Then do the operations to know the difference in the unit that you require:

long segundos = diff / 1000;
long minutos = segundos / 60;
long horas = minutos / 60;
long dias = horas / 24;

You must consider that when making the entire division, an error is introduced by truncation.

With this method you can achieve it and it is similar to what you are doing:

public String getDiferencia(Date fechaInicial, Date fechaFinal){

    long diferencia = fechaFinal.getTime() - fechaInicial.getTime();

    Log.i("MainActivity", "fechaInicial : " + fechaInicial);
    Log.i("MainActivity", "fechaFinal : " + fechaFinal);

    long segsMilli = 1000;
    long minsMilli = segsMilli * 60;
    long horasMilli = minsMilli * 60;
    long diasMilli = horasMilli * 24;

    long diasTranscurridos = diferencia / diasMilli;
    diferencia = diferencia % diasMilli;

    long horasTranscurridos = diferencia / horasMilli;
    diferencia = diferencia % horasMilli;

    long minutosTranscurridos = diferencia / minsMilli;
    diferencia = diferencia % minsMilli;

    long segsTranscurridos = diferencia / segsMilli;

    return "diasTranscurridos: " + diasTranscurridos + " , horasTranscurridos: " + horasTranscurridos +
            " , minutosTranscurridos: " + minutosTranscurridos + " , segsTranscurridos: " + segsTranscurridos;


}

We determine the dates on which we want to obtain the difference:

    SimpleDateFormat simpleDateFormat = new SimpleDateFormat("dd/M/yyyy hh:mm:ss");
    Date fechaI = null, fechaF = null;
    try {
        fechaI = simpleDateFormat.parse("1/6/2016 12:20:12");
         //fechaF puede ser la fecha actual o tu puedes asignarala,
         //por ejemplo: fechaF = simpleDateFormat.parse("2/6/2016 15:40:42");
         fechaF = new Date(System.currentTimeMillis());
    } catch (ParseException e) {
        e.printStackTrace();
    }

From the values we execute the getDiferencia() method with the start and end dates:

  Log.i(TAG,  getDiferencia(fechaI , fechaF));

The method internally prints the start and end date, so you can verify the values:

fechaInicial : Wed Jun 01 00:20:12 CDT 2016
fechaFinal : Thu Jun 02 11:32:16 CDT 2016

and get a string with the values of the difference:

diasTranscurridos: 1 , horasTranscurridos: 11 , minutosTranscurridos: 12 , segsTranscurridos: 4

I add my complete solution to my problem for future questions.

First Declare the variables to use.

private TextView countDown;
private CountDownTimer countDownTimer; 
private Date eventDate, presentDate;
private Calendar calendar;
private long initialTime;

Then we initialize the variable calendar with a new instance and send the date of our future event.

 calendar = Calendar.getInstance();
 calendar.set(Calendar.YEAR, 2016);
 calendar.set(Calendar.MONTH, Calendar.AUGUST);
 calendar.set(Calendar.DAY_OF_MONTH, 20);
 calendar.set(Calendar.HOUR_OF_DAY, 7);
 calendar.set(Calendar.MINUTE, 0);
 calendar.set(Calendar.SECOND, 0);

We now initialize the variables of Date that are eventDate = day of the event and presentDate = current day, the first gets its value from the calendar created earlier and the second from the current day.

 eventDate = calendar.getTime();
 presentDate = new Date();

Next step we obtain the difference in milli seconds by first assigning the day of the event and then the current day, we save the results in a variable type long and send them to Log to verify that the result is not negative, if so, the dates are misassigned.

long diff = eventDate.getTime() - presentDate.getTime();
Log.d("dateEvent", String.valueOf(eventDate));
Log.d("dateActual", String.valueOf(presentDate));
Log.d("diff", String.valueOf(diff)); 

Next step we obtain the equivalence in days, hours, minutes and seconds with these simple mathematical operations, all the results are stored in variables type long .

This will give us as a result, for example:

  

diff equals 5 days 3 hours 23 minutes and 5 seconds

/**
 * Explicación:
 * segundos = (milisegundos / 1 segundo en milisegundos) mod 60 segundos de un minuto
 */
long seconds =(diff/1000)%60;
long minutes=(diff/(1000*60))%60;
long hours=(diff/(1000*60*60))%24;
long days=(diff/(1000*60*60*24))%365;

As I need to do a counter to the date, I initialize the variable ìnitialTime with the value of the difference diff .

 initialTime = diff;

And then I assign the values to the constructor to initialize the variable countDownTimer :

countDownTimer = new CountDownTimer(initialTime, 1000) {

            @Override
            public void onTick(long millisUntilFinished) {

                int days = (int) ((millisUntilFinished / 1000) / 86400);
                int hours = (int) (((millisUntilFinished / 1000)
                        - (days * 86400)) / 3600);
                int minutes = (int) (((millisUntilFinished / 1000)
                        - (days * 86400) - (hours * 3600)) / 60);
                int seconds = (int) ((millisUntilFinished / 1000) % 60);

                String countDownText = String.format("%2d Dias %2d Hr %2d Min %2d Seg", days, hours, minutes, seconds);
                countDown.setText(countDownText);
            }

            @Override
            public void onFinish() {
                countDown.setText(DateUtils.formatElapsedTime(0));
            }

        }.start();

With this the CountDownTimer works from the current date to the event.