I. In your build.gradle add latest appcompat library, at the time 24.2.1
dependencies {
compile 'com.android.support:appcompat-v7:X.X.X'
// where X.X.X version
}
II. Make your activity extend android.support.v7.app.AppCompatActivity and implement the DatePickerDialog.OnDateSetListener interface.
public class MainActivity extends AppCompatActivity
implements DatePickerDialog.OnDateSetListener {
III. Create your DatePickerDialog setting a context, the implementation of the listener and the start year, month and day of the date picker.
DatePickerDialog datePickerDialog = new DatePickerDialog(
context, MainActivity.this, startYear, starthMonth, startDay);
IV. Show your dialog on the click event listener of your button
((Button) findViewById(R.id.myButton))
.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
datePickerDialog.show();
}
});