DatePicker,Acil

import android.app.Activity;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.TextView;
import java.util.Calendar;

public class Tarih extends Activity{
private TextView tvDisplayDate;
private DatePicker dpResult;
private Button btnHesapla;
private int year;
private int month;
private int day;
private EditText sure;
private int dnm;

static final int DATE_DIALOG_ID = 999;

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

setCurrentDateOnView();
addListenerOnButton();

}

public void setCurrentDateOnView() {

tvDisplayDate = (TextView) findViewById(R.id.textView6);
dpResult = (DatePicker) findViewById(R.id.datePicker1);
sure=(EditText) findViewById(R.id.editText2);
final Calendar c = Calendar.getInstance();
year = c.get(Calendar.YEAR);
month = c.get(Calendar.MONTH);
day = c.get(Calendar.DAY_OF_MONTH);

tvDisplayDate.setText(new StringBuilder()

.append(month + 1).append("-").append(day).append("-")
.append(year).append(" "));

dpResult.init(year, month, day, null);

}

public void addListenerOnButton() {

btnHesapla = (Button) findViewById(R.id.btnHesapla);

btnHesapla.setOnClickListener(new OnClickListener() {

public void onClick(View v) {

showDialog(DATE_DIALOG_ID);

}

});

}

@Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case DATE_DIALOG_ID:

return new DatePickerDialog(this, datePickerListener, year, month,day);
}
return null;
}

private DatePickerDialog.OnDateSetListener datePickerListener = new DatePickerDialog.OnDateSetListener() {

public void onDateSet(DatePicker view, int selectedYear,
int selectedMonth, int selectedDay) {
year = selectedYear;
month = selectedMonth;
day = selectedDay;

tvDisplayDate.setText(new StringBuilder().append(month + 1)
.append("-").append(day).append("-").append(year)
.append(" "));

dpResult.init(year, month, day, null);

}
};

}
androide yeni başladım sayılır.bir uygulama için tarih üzerinde işlem yapmam gerekiyor.bu tarihe dnm diye bir sure eklemem gerekiyor bunu nasıl yapacağım konusunda yardım eder misiniz? teşekkürler