DatePickerDialog in Android

Android DatePicker is a user interface control that is used to select the date by day, month, and year in the android application. DatePicker is used to ensure that the users will select a valid date. In android DatePicker having two modes, the first one shows the complete calendar and the second one shows the dates in the spinner view. One can create a DatePicker control in two ways either manually in the XML file or create it in the Activity file programmatically. We are going to do it programmatically by using Java.

Note: To implement DatePicker using Kotlin please refer to this.

Approach

Step 1: Create a New Project

To create a new project in Android Studio please refer to How to Create/Start a New Project in Android Studio. Note that select Java as the programming language.

Step 2: Working with activity_main.xml file

In the activity_main.xml file add only a TextView to display the selected date and a Button to select the date from the DatePickerDialog. Below is the complete code for the activity_main.xml file.

XML

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
    xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <TextView
        android:id="@+id/tvDate"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:text="Date" />

    <Button
        android:id="@+id/btPickDate"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_below="@+id/tvDate"
        android:layout_centerInParent="true"
        android:text="Pick Date" />

</RelativeLayout>

Step 3: Create a new class and names as DatePicker

Now create a new class by going to the package and right-click on it and select new and then Java Class. Name the class as DatePicker and its superclass as DialogFragment (androidx.fragment.app.DialogFragment) and click OK.

Now override a method onCreateDialog and instead of returning super.onCreateDialog return an instance of DatePickerDialog. 

@NonNull

   @Override

   public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {

       return new DatePickerDialog();

   }

Now pass parameters to the constructor of DatePickerDialog which requires context, OnDateSetListener, year, month, dayOfMonth.

• Pass the getActivity method for the context.
• For OnDateSetListener typecast the getActivity method to OnDateSetListener.
• For the year, month, and dayOfMonth create an instance of calendar class and assign the year, month, and dayOfMonth to variables of type int.
• Pass year and month and dayOfMonth so that when the DatePickerDialog opens it has the current date.

@NonNull

@Override

public Dialog

onCreateDialog(@Nullable Bundle savedInstanceState)

{

   Calendar mCalendar = Calendar.getInstance();

   int year = mCalendar.get(Calendar.YEAR);

   int month = mCalendar.get(Calendar.MONTH);

   int dayOfMonth = mCalendar.get(Calendar.DAY_OF_MONTH);

   return new DatePickerDialog(

       getActivity(),

       (DatePickerDialog.OnDateSetListener)getActivity(),

       year, month, dayOfMonth);

}

The complete code for the DatePicker.java class is given below. 

Java

package tutorials.droid.datepicker;

import android.app.DatePickerDialog;
import android.app.Dialog;
import android.os.Bundle;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.DialogFragment;
import java.util.Calendar;

public class DatePicker extends DialogFragment {
    @NonNull
    @Override
    public Dialog onCreateDialog(@Nullable Bundle savedInstanceState) {
        Calendar mCalendar = Calendar.getInstance();
        int year = mCalendar.get(Calendar.YEAR);
        int month = mCalendar.get(Calendar.MONTH);
        int dayOfMonth = mCalendar.get(Calendar.DAY_OF_MONTH);
        return new DatePickerDialog(getActivity(), (DatePickerDialog.OnDateSetListener)
                getActivity(), year, month, dayOfMonth);
    }
}

Step 4: Working with MainActivity.java file

Now In the MainActivity.java file, create an object of both TextView and Button and map the components(TextView and Button) with their ids. 

TextView tvDate;

Button btPickDate;

tvDate = findViewById(R.id.tvDate);

btPickDate = findViewById(R.id.btPickDate);

Implement OnDateSetListener of DatePickerDialog class and override onDateSet() method.  The  onDateSet() method will set the date after selection in the tvDate TextView. 

 @Override

   public void onDateSet(DatePicker view, int year, int month, int dayOfMonth)

 {

       // Create a Calendar instance

       Calendar mCalendar = Calendar.getInstance();

       // Set static variables of Calendar instance

       mCalendar.set(Calendar.YEAR,year);

       mCalendar.set(Calendar.MONTH,month);

       mCalendar.set(Calendar.DAY_OF_MONTH,dayOfMonth);

       // Get the date in form of string

       String selectedDate = DateFormat.getDateInstance(DateFormat.FULL).format(mCalendar.getTime());

       // Set the textview to the selectedDate String

       tvDate.setText(selectedDate);

}

In the onClick() method implement setOnClickListener of btPickDate. Create an instance of DatePicker(our class). Use the show method of the instance and pass getSupportFragmentManager() and a Tag. The complete code for the MainActivity.java file is given below.

Java

package tutorials.droid.datepicker;

import android.app.DatePickerDialog;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.DatePicker;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;
import java.text.DateFormat;
import java.util.Calendar;

public class MainActivity extends AppCompatActivity implements DatePickerDialog.OnDateSetListener {
    TextView tvDate;
    Button btPickDate;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tvDate = findViewById(R.id.tvDate);
        btPickDate = findViewById(R.id.btPickDate);
        btPickDate.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                // Please note that use your package name here
                tutorials.droid.datepicker.DatePicker mDatePickerDialogFragment;
                mDatePickerDialogFragment = new tutorials.droid.datepicker.DatePicker();
                mDatePickerDialogFragment.show(getSupportFragmentManager(), "DATE PICK");
            }
        });
    }

    @Override
    public void onDateSet(DatePicker view, int year, int month, int dayOfMonth) {
        Calendar mCalendar = Calendar.getInstance();
        mCalendar.set(Calendar.YEAR, year);
        mCalendar.set(Calendar.MONTH, month);
        mCalendar.set(Calendar.DAY_OF_MONTH, dayOfMonth);
        String selectedDate = DateFormat.getDateInstance(DateFormat.FULL).format(mCalendar.getTime());
        tvDate.setText(selectedDate);
    }
}

Output: Run on Emulator