private int year;
    private int monthOfYear;
    private int dayOfMonth;

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

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

        Calendar calendar = Calendar.getInstance();
        year = calendar.get(Calendar.YEAR);
        monthOfYear = calendar.get(Calendar.MONTH);
        dayOfMonth = calendar.get(Calendar.DAY_OF_MONTH);

        button.setOnClickListener(new OnClickListener() {

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

                DatePickerDialog pickerDialog = new DatePickerDialog(MainActivity.this, new OnDateSetListener() {

                    @Override
                    public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
                        // TODO Auto-generated method stub
                        Toast.makeText(MainActivity.this, year + "年" + monthOfYear + "月" + dayOfMonth + "日", 1).show();
                    }
                }, year, monthOfYear, dayOfMonth);

                pickerDialog.show();
            }
        });
    }