DatePicker / DatePickerDialog - Android Widgets Example

package com.myapp;

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

public class MainActivity extends Activity {
	
    private EditText editT1;
    private Button btn1;

    private int mYear;
    private int mMonth;
    private int mDay;

    static final int DATE_DIALOG_ID = 0;
	
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
       
        
        // editText1
        editT1 = (EditText) findViewById(R.id.editText1);
        
        // button1
        btn1 = (Button) findViewById(R.id.button1);

        // add a click listener to the button
        btn1.setOnClickListener(new View.OnClickListener() {
            public void onClick(View v) {
                showDialog(DATE_DIALOG_ID);
            }
        });

        // get the current date
        final Calendar c = Calendar.getInstance();
        mYear = c.get(Calendar.YEAR);
        mMonth = c.get(Calendar.MONTH);
        mDay = c.get(Calendar.DAY_OF_MONTH);

        // display the current date
        updateCurrentDate();
		
    }

    @Override
    protected Dialog onCreateDialog(int id) {
        switch (id) {
        case DATE_DIALOG_ID:
            return new DatePickerDialog(this,
                        mDateSetListener,
                        mYear, mMonth, mDay);
        }
        return null;
    }
    
    // updates the date we display in the editText
    private void updateCurrentDate() {
    	editT1.setText(
            new StringBuilder()
                    // Month is 0 based so add 1
                    .append(mMonth + 1).append("-")
                    .append(mDay).append("-")
                    .append(mYear).append(" "));
    }
    
    private DatePickerDialog.OnDateSetListener mDateSetListener =
            new DatePickerDialog.OnDateSetListener() {

                public void onDateSet(DatePicker view, int year, 
                                      int monthOfYear, int dayOfMonth) {
                    mYear = year;
                    mMonth = monthOfYear;
                    mDay = dayOfMonth;
                    updateCurrentDate();
                }
     };
        
    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }
    
}