Incrementing the date taken from a date time picker dialog by 39 weeks

Question

Hey guys i am working on an application that can be used to predict the due date of a babies birth but i have failed to figure out how to increment the date from the date time picker dialog below is my code

public class Dday extends Activity implements OnClickListener{

private EditText fromDateEtxt;

private DatePickerDialog fromDatePickerDialog;

private SimpleDateFormat dateFormatter;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_dday);

    dateFormatter = new SimpleDateFormat("dd-MM-yyyy", Locale.US);

    findViewsById();

    setDateTimeField();
}

private void findViewsById() {
    fromDateEtxt = (EditText) findViewById(R.id.etxt_fromdate);    
    fromDateEtxt.setInputType(InputType.TYPE_NULL);
    fromDateEtxt.requestFocus();
}

private void setDateTimeField() {
    fromDateEtxt.setOnClickListener(this);

    Calendar newCalendar = Calendar.getInstance();
    fromDatePickerDialog = new DatePickerDialog(this, new OnDateSetListener() {

        public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
            Calendar newDate = Calendar.getInstance();
            newDate.set(year, monthOfYear, dayOfMonth);
            fromDateEtxt.setText(dateFormatter.format(newDate.getTime()));
        }

    },newCalendar.get(Calendar.YEAR), newCalendar.get(Calendar.MONTH), newCalendar.get(Calendar.DAY_OF_MONTH));
}


@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.dday, menu);
    return true;
}

public void showDate (View view)
{
    // Adding the days to the date 

    // Button action

    Intent dts = new Intent(this,Details.class);

    startActivity(dts);
}

@Override
public void onClick(View view) {
    // TODO Auto-generated method stub

    if(view == fromDateEtxt) {
        fromDatePickerDialog.show();
    }
}

score 0 · Answer 1 · answered Sep 15 '15 at 21:17

0

You can increment a Calendar object by 39 weeks with something like this:

Calendar cal = Calendar.getInstance();
cal.add(Calendar.WEEK_OF_YEAR, 39);

answered Sep 15 '15 at 21:17

M3SSYM4RV1N

135
10

score 0 · Answer 2 · edited May 23 '17 at 12:14

0

public void onDateSet(DatePicker view, int selectedYear, int selectedMonth, int selectedDay) {
    Calendar c = Calendar.getInstance();
    c.set(selectedYear, selectedMonth, selectedDay);
    c.add(Calendar.DATE, 39);
}

for more see this thread How do I set the date for a date picker?

edited May 23 '17 at 12:14

Community

1
1

answered Sep 15 '15 at 21:24

Deepak Goyal

4,747
2
21
46

Hey just a quick one the code above if i just added it to my code would it work fine ? direct into this public void showDate (View view) { // Adding the days to the date // Button action Intent dts = new Intent(this,Details.class); startActivity(dts); } can than work ? – Joe Kasedde Sep 16 '15 at 08:09
yes, you can update the date in you showdate method. But for his you have to keep the reference of user selected date in calendar. – Deepak Goyal Sep 16 '15 at 16:21

score 0 · Accepted Answer · answered Sep 16 '15 at 16:35

You can use the Calendar Object and create a date from Today and add 39 weeks using the Calendar class by setting Date objects based on the Calendar and modified Calendar like so:

    // Formatter for readable comparison
    DateFormat sdf = new SimpleDateFormat("MM dd yyyy", Locale.getDefault());

    // Today
    Calendar now = Calendar.getInstance();
    Date dateToday = new Date();
    dateToday.setTime(now.getTimeInMillis());

    // 39 weeks from today
    Date futureDate = new Date();
    // Calendar supports roll over with year so no need to worry about modifying year separate
    now.add(Calendar.WEEK_OF_YEAR, 39); 
    futureDate.setTime(now.getTimeInMillis());

    // Print out for comparison
    System.out.println(sdf.format(dateToday));
    System.out.println(sdf.format(futureDate));

Which prints out:

I/System.out﹕ 09 16 2015 <-- Today
I/System.out﹕ 06 15 2016 <-- 39 weeks later

great work! Thank you very much and would you mind helping me check if my sample app meets basic requirements and may be patch it where you find loop holes ? — Joe Kasedde, Sep 17 '15 at 00:08

Incrementing the date taken from a date time picker dialog by 39 weeks

3 Answers3