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How do I find days between two date pickers in android? [duplicate]

This question already has answers here:
What is a NullPointerException, and how do I fix it?
(12 answers)
Android Days between two dates
(19 answers)
How to calculate number of days between two datepicker in android and display in the edit text
(3 answers)
Closed 2 years ago.
I have been trying to find the difference between two dates from date picker. My app is getting crashed for null point object exception.
java.lang.NullPointerException: Attempt to invoke virtual method 'long java.util.Date.getTime()' on a null object reference
package com.cksapp.dateformat;
import androidx.appcompat.app.AppCompatActivity;
import android.app.DatePickerDialog;
import android.graphics.Color;
import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.TextView;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;
import java.util.concurrent.TimeUnit;
import static java.util.Calendar.YEAR;
public class MainActivity extends AppCompatActivity {
TextView t1, t2, t3, t4, difference;
Button b1;
Date datefrom, dateOne;
Date dateto, dateTwo;
Date d1, d2;
private DatePickerDialog.OnDateSetListener mDate1;
private DatePickerDialog.OnDateSetListener mDate2;
private Object Date;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
t1 = findViewById(R.id.textView);
t2 = findViewById(R.id.textView2);
t3 = findViewById(R.id.textView3);
t4 = findViewById(R.id.textView4);
difference = findViewById(R.id.textView7);
b1 = findViewById(R.id.button);
t1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Calendar c = Calendar.getInstance();
int year = c.get(YEAR);
int month = c.get(Calendar.MONTH);
int day = c.get(Calendar.DAY_OF_MONTH);
DatePickerDialog dialog = new DatePickerDialog(MainActivity.this,
android.R.style.Theme_Holo_Dialog_MinWidth,
mDate1,
year,month,day);
//Date dateOne = c.getTime();
dialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
dialog.show();
}
});
mDate1 = new DatePickerDialog.OnDateSetListener() {
#Override
public void onDateSet(DatePicker view, int year, int month, int dayOfMonth) {
month = month + 1;
String datefrom = month + "/" + dayOfMonth + "/" + year;
t2.setText(datefrom);
}
};
//next
t3.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
Calendar c = Calendar.getInstance();
int year = c.get(YEAR);
int month = c.get(Calendar.MONTH);
int day = c.get(Calendar.DAY_OF_MONTH);
DatePickerDialog dialog = new DatePickerDialog(MainActivity.this,
android.R.style.Theme_Holo_Dialog_MinWidth,
mDate2,
year,month,day);
dialog.getWindow().setBackgroundDrawable(new ColorDrawable(Color.TRANSPARENT));
dialog.show();
}
});
mDate2 = new DatePickerDialog.OnDateSetListener() {
#Override
public void onDateSet(DatePicker view, int year, int month, int dayOfMonth) {
month = month + 1;
String dateto = month + "/" + dayOfMonth + "/" + year;
t4.setText(dateto);
}
};
b1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
//This is where I tried performing subtraction but it didn't work
long diff = dateto.getTime() - datefrom.getTime();
difference.setText((int) diff);
}
});
}
}

By putting String in front of dateto, you've made it a declaration of a local variable rather than a reference to the instance variable (that you're trying to access later). So it will forever be null. Change:
String dateto = month + "/" + dayOfMonth + "/" + year;
to
dateto = new Date(month, dayOfMonth, year); // no "String"
However, the Date constructor is deprecated and using Date is strongly discouraged, so you should really use something like:
import java.time.LocalDate;
import java.time.Instant;
import java.time.ZoneOffset;
//...
Instant dateto;
//...
LocalDate localDate = LocalDate.of(month, dayOfMonth, year);
dateto = localDate.atStartOfDay(ZoneOffset.UTC).toInstant();

Never mind, I figured out the answer using joda library
I have made it with different UI, joda library dependancy is included in build.gradle. It worked perfect.
package com.cksapp.newdateformat;
import androidx.appcompat.app.AppCompatActivity;
import android.app.DatePickerDialog;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.TextView;
import android.widget.Toast;
import net.danlew.android.joda.JodaTimeAndroid;
import org.joda.time.DateMidnight;
import org.joda.time.DateTime;
import org.joda.time.Days;
import org.joda.time.LocalDate;
import org.joda.time.Period;
import org.joda.time.PeriodType;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import static org.joda.time.Days.daysBetween;
public class MainActivity extends AppCompatActivity {
TextView t1, t2, t3, t4, today;
Button b1, b2, b3;
String date1, date2, todaydate;
int daysy, daysm, daysd, daysss;
DatePickerDialog.OnDateSetListener dateSetListener;
DatePickerDialog.OnDateSetListener dateSetListener2;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
JodaTimeAndroid.init(this);
today = findViewById(R.id.today);
t1 = findViewById(R.id.starttext);
t2 = findViewById(R.id.endtext);
t3 = findViewById(R.id.daystext);
t4 = findViewById(R.id.daysinyears);
b1 = findViewById(R.id.startbutton);
b2 = findViewById(R.id.endbutton);
b3 = findViewById(R.id.calculatebutton);
Calendar c = Calendar.getInstance();
final int year = c.get(Calendar.YEAR);
final int month = c.get(Calendar.MONTH);
final int day = c.get(Calendar.DAY_OF_MONTH);
SimpleDateFormat sdf = new SimpleDateFormat("dd/MM/yyyy");
todaydate = sdf.format(Calendar.getInstance().getTime());
today.setText("Today is " + todaydate);
b1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
DatePickerDialog datePickerDialog = new DatePickerDialog(v.getContext(),dateSetListener,year,month,day);
datePickerDialog.getDatePicker().setMaxDate(new Date().getTime());
datePickerDialog.show();
}
});
dateSetListener = new DatePickerDialog.OnDateSetListener() {
#Override
public void onDateSet(DatePicker view, int year, int month, int dayOfMonth) {
month = month + 1;
date1 = dayOfMonth + "/" + month + "/" + year;
t1.setText(date1);
}
};
b2.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
DatePickerDialog datePickerDialog2 = new DatePickerDialog(v.getContext(),dateSetListener2,year,month,day);
datePickerDialog2.getDatePicker().setMaxDate(new Date().getTime());
datePickerDialog2.show();
}
});
dateSetListener2 = new DatePickerDialog.OnDateSetListener() {
#Override
public void onDateSet(DatePicker view, int year, int month, int dayOfMonth) {
month = month + 1;
date2 = dayOfMonth + "/" + month + "/" + year;
t2.setText(date2);
}
};
b3.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
if(date1 == null || date2 == null){
Toast.makeText(getApplicationContext(), "Please enter the date field(s)",Toast.LENGTH_SHORT).show();
}
else {
SimpleDateFormat sdf1 = new SimpleDateFormat("dd/MM/yyyy");
try {
Date d1 = sdf1.parse(date1);
Date d2 = sdf1.parse(date2);
long fromdate = d1.getTime();
long todate = d2.getTime();
Period p = new Period(fromdate, todate, PeriodType.yearMonthDay());
int years = p.getYears();
int months = p.getMonths();
int days = p.getDays();
t4.setText(years + " years" + months + " months" + days + " days");
int diff = (int) (d2.getTime() - d1.getTime());
int YO = diff/86400000;
//Log.d("Days", String.valueOf(diff));
t3.setText(String.valueOf(YO));
} catch (ParseException e) {
e.printStackTrace();
}
}}
});
}
}

How do I calculate time difference between two time pickers in android?

I am able to find out the difference between two time intervals, but when the time 1st 12:00am or 00:00 and 2nd time is any other time, I am not getting accurate difference. Instead I am getting a negative difference. Upon debugging I figured out the time is actually taking of the year 1970 January. I am unable to correct it by taking today's time and calculate the difference.
package com.cksapp.memoryin;
import androidx.appcompat.app.AppCompatActivity;
import android.app.TimePickerDialog;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.TimePicker;
import android.widget.Toast;
import com.google.firebase.Timestamp;
import com.google.firebase.firestore.FirebaseFirestore;
import com.google.firebase.firestore.FirebaseFirestoreSettings;
import java.security.CodeSigner;
import java.sql.Time;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
//import java.util.Date;
public class HourlyCalculator extends AppCompatActivity {
EditText wage;
TextView t1, t2, t3;
ImageView i1, i2;
Button b1;
int minutestotal;
String timex, timey;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.calculator_hourly);
wage = findViewById(R.id.hourlyrate);
t1 = findViewById(R.id.starttimetext);
t2 = findViewById(R.id.endtimetext);
t3 = findViewById(R.id.finaltime);
i1 = findViewById(R.id.startimage);
i2 = findViewById(R.id.endimage);
b1 = findViewById(R.id.calculatebutton);
Calendar c = Calendar.getInstance();
final int hour = c.get(Calendar.HOUR_OF_DAY);
final int mins = c.get(Calendar.MINUTE);
i1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
final TimePickerDialog time = new TimePickerDialog(HourlyCalculator.this, new TimePickerDialog.OnTimeSetListener() {
#Override
public void onTimeSet(TimePicker view, int hourOfDay1, int minute1) {
timex = hourOfDay1 + ":" + minute1;
t1.setText(timex);
Log.d("Time1", timex);
}
},hour, mins, true);
time.show();
}
});
i2.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
final TimePickerDialog time2 = new TimePickerDialog(HourlyCalculator.this, new TimePickerDialog.OnTimeSetListener() {
#Override
public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
timey = hourOfDay + ":" + minute;
t2.setText(timey);
Log.d("Time1", timey);
}
},hour,mins,true);
time2.show();
}
});
b1.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
SimpleDateFormat sdf = new SimpleDateFormat("HH:mm");
try {
Date a = sdf.parse(timex);
Date b = sdf.parse(timey);
long difference = a.getTime() - b.getTime();
Log.d("Time", String.valueOf(difference));
/* minutestotal = (int) (difference/60000);
Log.d("Timearey", String.valueOf(minutestotal));
int totalwageinitital = Integer.parseInt(wage.getText().toString());
double totalwagepermin = totalwageinitital/60;
double finalprice = minutestotal * totalwagepermin;
t3.setText(String.valueOf(finalprice));*/
} catch (ParseException e) {
e.printStackTrace();
}
}
});
}
}

You are parsing the time using only hours and minutes, without providing the year, month and day the sdf will assume Jan 1st, 1970.
You should do this in a different way: initialize a calendar object for each date using Calendar.getInstance(), this will give you an instance with today's date, then set the hours and minutes for those 2 instances according to the hours and minutes in the picker and check the difference between their timeInMilliseconds.
Calendar time = Calendar.getInstance();
time.set(Calendar.HOUR_OF_DAY, hour);
time.set(Calendar.MINUTE, minute);

Can my Date Picker Print my date picked on the EditText not on Toast?

I have this code where when I picked a date it only shows on toast, is there any way for it to be inserted in my EditText? Here is my code.
package com.example.kun.carkila;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.view.View;
import android.widget.DatePicker;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.Toast;
import java.util.Calendar;
public class RegisterActivity extends AppCompatActivity {
EditText etFirstname, etMiddlename, etLastname, etBirthDate, etAddress, etUsername, etPassword;
Spinner spRole;
int year_x,month_x,day_x;
static final int DIALOG_ID = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_register);
showDialogOnButtonClick();
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
final Calendar cal = Calendar.getInstance();
year_x = cal.get(Calendar.YEAR);
month_x = cal.get(Calendar.MONTH);
day_x = cal.get(Calendar.DAY_OF_MONTH);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
}
public void showDialogOnButtonClick(){
etBirthDate = (EditText)findViewById(R.id.etBirthDate);
etBirthDate.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
showDialog(DIALOG_ID);
}
});
}
#Override
protected Dialog onCreateDialog(int id) {
if(id == DIALOG_ID) {
return new DatePickerDialog(this, dpListener, year_x, month_x, day_x);
}
return null;
}
DatePickerDialog.OnDateSetListener dpListener
= new DatePickerDialog.OnDateSetListener() {
#Override
public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
year_x = year;
month_x = monthOfYear;
day_x = dayOfMonth;
Toast.makeText(RegisterActivity.this, year_x + "/" + month_x + "/" + day_x,Toast.LENGTH_SHORT).show();
}
};
}
And yes I set my EditText clickable to show the datepicker lol. Can i instert the date picked where I can also click on my EditText? Thank you for the help :D

Remove the toast :
Toast.makeText(RegisterActivity.this, year_x + "/" + month_x + "/" + day_x,Toast.LENGTH_SHORT).show();
then set date in edittext :
etBirthDate.setText(year_x + "/" + month_x + "/" + day_x);

This should work
#Override
public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
year_x = year;
month_x = monthOfYear;
day_x = dayOfMonth;
etBirthDate.setText(year_x + "/" + month_x + "/" + day_x);
}
};

DatePickerDialog showing abnormal behaviour in android 5.1 when timezone is changed

I have to show calender using DatePickerDialog.
The below code is used:
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.TimeZone;
import android.app.Activity;
import android.app.AlarmManager;
import android.app.DatePickerDialog;
import android.app.Dialog;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.CalendarView;
import android.widget.DatePicker;
import android.widget.DatePicker.OnDateChangedListener;
import android.widget.TextView;
import android.widget.Toast;
public class DatePickerExample extends Activity {
private TextView Output;
private Button changeDate;
private Boolean mEnableNativeCalGridView = null;
String timeZone;
public static TimeZone tz;
private int year;
private int month;
DatePickerDialog d;
public Calendar c;
SimpleDateFormat sdf;
private int day;
public static IntentFilter s_intentFilter;
static final int DATE_PICKER_ID = 1111;
static{
s_intentFilter = new IntentFilter();
s_intentFilter.addAction(Intent.ACTION_TIME_TICK);
s_intentFilter.addAction(Intent.ACTION_TIMEZONE_CHANGED);
s_intentFilter.addAction(Intent.ACTION_TIME_CHANGED);
}
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
registerReceiver(m_timeChangedReceiver, s_intentFilter);
Output = (TextView) findViewById(R.id.Output);
changeDate = (Button) findViewById(R.id.changeDate);
// sdf = new SimpleDateFormat("EEE, MMM d, ''yy");//Wed, Jul 4, '01
// Show current date
Output.setText(new StringBuilder()
// Month is 0 based, just add 1
.append(month + 1).append("-").append(day).append("-")
.append(year).append(" "));
// Button listener to show date picker dialog
changeDate.setOnClickListener(new OnClickListener() {
#SuppressWarnings("deprecation")
#Override
public void onClick(View v) {
// On button click show datepicker dialog
showDialog(DATE_PICKER_ID);
}
});
}
#Override
protected void onPrepareDialog(int id, Dialog dialog) {
switch (id) {
case DATE_PICKER_ID:
((DatePickerDialog) dialog).updateDate(
c.get(Calendar.YEAR),
c.get(Calendar.MONTH),
c.get(Calendar.DAY_OF_MONTH));
}
}
#Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case DATE_PICKER_ID:
// open datepicker dialog.
// set date picker for current date
// add pickerListener listner to date picker
sdf = new SimpleDateFormat("EEE MMM dd HH:mm:ss z yyyy");
tz = TimeZone.getDefault();
System.out.println("TimeZone "+tz.getDisplayName(false, TimeZone.SHORT)+" Timezon id :: " +tz.getID());
timeZone = tz.getDisplayName(false, TimeZone.SHORT);
c= Calendar.getInstance();
c.setTimeZone(tz);
year = c.get(Calendar.YEAR);
month = c.get(Calendar.MONTH);
day = c.get(Calendar.DAY_OF_MONTH);
d = new DatePickerDialog(DatePickerExample.this, pickerListener, year, month,day);
setMinMaxdate();
return d;
}
return null;
}
////////////////////Fix for issue on OS 5.1 //////////////////////
public long getDateFormatted(String date){
String givenDateString = date;
long timeInMilliseconds = 0;
try {
Date mDate = sdf.parse(givenDateString);
timeInMilliseconds = mDate.getTime();
System.out.println("Date in milli :: " + timeInMilliseconds);
} catch (ParseException e) {
e.printStackTrace();
}
return timeInMilliseconds;
}
//////////////////////////////////////////
private DatePicker.OnDateChangedListener newchange= new OnDateChangedListener(){
#Override
public void onDateChanged(DatePicker view,
int year, int monthOfYear,int dayOfMonth) {
Toast.makeText(getApplicationContext(),
"onDateChanged", Toast.LENGTH_SHORT).show();
}};
DatePicker datePicker;
public void setMinMaxdate() {
//Time zone calculation
//TimeZone.setDefault(tz);
///////////////////////
long calEvtEndDate= getDateFormatted("Sun May 31 23:59:59 "+timeZone+" 2015");//System.currentTimeMillis();
long calEvtStartDate= getDateFormatted("Wed May 13 00:00:00 "+timeZone+" 2015");//System.currentTimeMillis()/2;
// long calEvtEndDate = getDateFormatted("Sun, may 31, '15");
//long calEvtStartDate = getDateFormatted("Wed, may 13, '15");
if(d != null){
datePicker = d.getDatePicker();
if(mEnableNativeCalGridView != null){
datePicker.setCalendarViewShown(mEnableNativeCalGridView.booleanValue());
}
// If Start Date is Greater than End Date then we are showing from valid StartDate
// value and we are not setting the maxdate.
if (calEvtStartDate > calEvtEndDate) {
datePicker.setMinDate(calEvtStartDate);
} else {
if (calEvtStartDate > 0) { // If Only ValidStart date is provided, then setting the minDate.
datePicker.setMinDate(calEvtStartDate);
}
if (calEvtEndDate > 0) { // If Only ValidEnd date is provided, then setting the maxDate.
datePicker.setMaxDate(calEvtEndDate);
}
}
}
}
#Override
protected void onResume() {
// TODO Auto-generated method stub
super.onResume();
System.out.println("-------resumed");
}
public DatePickerDialog.OnDateSetListener pickerListener = new DatePickerDialog.OnDateSetListener() {
// when dialog box is closed, below method will be called.
#Override
public void onDateSet(DatePicker view, int selectedYear,
int selectedMonth, int selectedDay) {
//view.updateDate(year, month, day);
System.out.println("---------------datesetchange");
year = selectedYear;
month = selectedMonth;
day = selectedDay;
// Show selected date
Output.setText(new StringBuilder().append(month + 1)
.append("-").append(day).append("-").append(year)
.append(" "));
}
};
public void onDestroy() {
super.onDestroy();
unregisterReceiver(m_timeChangedReceiver);
}
private final BroadcastReceiver m_timeChangedReceiver = new BroadcastReceiver() {
#Override
public void onReceive(Context context, Intent intent) {
final String action = intent.getAction();
if (action.equals(Intent.ACTION_TIME_CHANGED) ||
action.equals(Intent.ACTION_TIMEZONE_CHANGED))
{
System.out.println("timezone changed---"+action.toString());
tz = TimeZone.getDefault();
System.out.println("TimeZone "+tz.getDisplayName(false, TimeZone.SHORT)+" Timezon id :: " +tz.getID());
timeZone = tz.getDisplayName(false, TimeZone.SHORT);
// Intent intent1 = getIntent();
// finish();
// startActivity(intent1);
showDialog(DATE_PICKER_ID);
}
}
};
}
When the app is running, I go to the settings and change the Timezone to such a value so that the current date will change. Now when we select any date in the dialog, it behaves abnormally and goes to other date. I have used setMinDate() and setMaxDate() methods. This happens only in Android OS 5.1.
Any idea or help? Thanks in advance.

How to set the date from DatePicker dialog for multiple calls

Good day, can't seem to find a solution for this. i have 2 buttons that when pressed, opens a datepickerdialog, but my problem now is , how can i set them to the appropriate button on OnDateSet method. I am using a DialogFragment for the date and then implementing the DateListener in my activity. I have tried using getTag() but no success in getting the tag. here is what i tried:
public void showfromDatePickerDialog(View v) {
DialogFragment dateFragment = new DateDialogFragment();
dateFragment.show(getSupportFragmentManager(), "fromdatePicker");
}
public void showtoDatePickerDialog(View v) {
DialogFragment dateFragment = new DateDialogFragment();
dateFragment.show(getSupportFragmentManager(), "todatePicker");
}
public void onDateSet(DatePicker view, int year, int month, int day) {
StringBuilder builder = new StringBuilder();
builder.append(day).append("-")
.append(month).append("-")
.append(year);
String text= builder.toString();
if(view.getTag().toString().equals("fromdatePicker")) { // error here
Log.d(TAG, "got here" + text);
fromdate.setText(text);
}
if(view.getTag() == "todatePicker") {
todate.setText(text);
}
any ideas how to implement this? i keep seeing solutions about using 2 different DialogFragment class but am guessing there should be another way. or am i wrong? Thank you

ok, i have a work around for these. which can be helpful for anyone with this problem. if its slightly incorrect please let me know and i can change it. but this is what i did to solve this issue.
in on DateSet:
public void onDateSet(DatePicker view, int year, int month, int day) {
StringBuilder builder = new StringBuilder();
builder.append(day).append("-")
.append(month).append("-")
.append(year);
String text= builder.toString();
FragmentManager fragmanager = getSupportFragmentManager();
if(fragmanager.findFragmentByTag("fromdatePicker") != null) {
Log.d(TAG, "got here" + text);
fromdate.setText(text);
}
// if(view.getTag() == "todatePicker") {
if(fragmanager.findFragmentByTag("todatePicker") != null) {
todate.setText(text);
}
that way you can use the same dateListener for multiple calls and set the date appropriately based on the tag that was passed when calling show on the dialog.

Use below code of DatePicker Dialog.
private int mYear;
private int mMonth;
private int mDay;
Calendar cal4DatePicker = Calendar.getInstance();
Button btnDOB=findviewbyId(R.id.btndob);
private DatePickerDialog.OnDateSetListener mDateSetListener = new DatePickerDialog.OnDateSetListener() {
public void onDateSet(DatePicker view, int year, int monthOfYear,
int dayOfMonth) {
mYear = year;
mMonth = monthOfYear;
mDay = dayOfMonth;
cal4DatePicker.set(Calendar.YEAR, mYear);
cal4DatePicker.set(Calendar.MONTH, mMonth);
cal4DatePicker.set(Calendar.DAY_OF_MONTH, mDay);
btnDOB.setText(new StringBuilder()
.append(mDay).append("-").append(mMonth).append("-").append(mYear).append(" "));
}
};
on btnDOB you need to set click listner to show this DatePicker Dialog.

I have try same thing with Time Picker only. You can try out and set same for date picker also.
package com.example.toolboxtest;
import java.text.Format;
import java.text.SimpleDateFormat;
import java.util.Calendar;
import java.util.Date;
import java.util.GregorianCalendar;
import android.app.Dialog;
import android.app.TimePickerDialog;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TimePicker;
public class MainActivity extends FragmentActivity implements OnClickListener {
Button testBtn;
EditText testET;
static final int TIME_DIALOG_ID = 0;
int mHour = 0;
int mMinute = 0;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
testBtn = (Button) findViewById(R.id.testBTn);
testET = (EditText) findViewById(R.id.testET);
testBtn.setOnClickListener(this);
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
#Override
public void onClick(View v) {
switch(v.getId()){
case R.id.testBTn:
showDialog(TIME_DIALOG_ID);
break;
}
}
private TimePickerDialog.OnTimeSetListener mTimeSetListener = new TimePickerDialog.OnTimeSetListener() {
public void onTimeSet(TimePicker view, int hourOfDay, int minute) {
mHour=hourOfDay;
mMinute = minute;
// myPrefs = ImportantDateReminderActivity.this.getSharedPreferences("myPrefs",MODE_WORLD_WRITEABLE);
// prefsEditor = myPrefs.edit();
// prefsEditor.putInt("hour", mHour);
// prefsEditor.putInt("minute", mMinute);
// prefsEditor.putString("a", a);
// prefsEditor.commit();
if(mHour==12){
//reminderSetTime.setText(new StringBuilder().append("12").append(":").append((minute)+" PM"));
testET.setText(mHour+":"+mMinute+" "+"PM");
}
else
updateTimeDisplay();
}
};
private void updateTimeDisplay() {
try {
Format formatter;
SimpleDateFormat df = new SimpleDateFormat("hh:mm");
Date d = df.parse(mHour + ":" + mMinute);
Calendar gc = new GregorianCalendar();
gc.setTime(d);
//gc.add(Calendar.HOUR, 0);
Date d2 = gc.getTime();
formatter = new SimpleDateFormat("hh:mm a");
String time = formatter.format(d2);
System.out.println("The TIME is: "+time);
testET.setText(time);
String hour = new SimpleDateFormat("hh").format(d2);
String minute = new SimpleDateFormat("mm").format(d2);
String a = new SimpleDateFormat("a").format(d2);
System.out.println("The Hour is: "+hour+ " "+minute+ " " +a);
/*myPrefs = this.getSharedPreferences("myPrefs",MODE_WORLD_WRITEABLE);
prefsEditor = myPrefs.edit();
prefsEditor.putInt("hour", Integer.parseInt(hour));
prefsEditor.putInt("minute", Integer.parseInt(minute));
prefsEditor.putString("a", a);
prefsEditor.putString("complateTime", time);
prefsEditor.commit();*/
//addTwoMonthNotification();
} catch (Exception e) {
e.printStackTrace();
}
}
#Override
protected Dialog onCreateDialog(int id) {
switch (id) {
case TIME_DIALOG_ID:
return new TimePickerDialog(this,mTimeSetListener, mHour, mMinute, false);
}
return null;
}
}
Hope it will help you.
Please let me know if there is any issue.