Well, I don't know what the parent theme you use for the Date Picker theme is. Say you have a custom theme for your date picker, as shown below,
<style name="yourCustomStyle" parent="Theme.AppCompat.Light">
Ctrl + Theme.AppCompat.Light, ;), , , , , , .
, , ,
android:textColorPrimaryInverse
.
<style name="yourCustomStyle" parent="Theme.AppCompat.Light">
<item name="colorAccent">@color/blue</item>
<item name="android:textColorPrimaryInverse">@color/yellow</item>
.. other
</style>
( ), !
new DatePickerDialog(MainActivity.this, R.style.yourCustomStyle, new DatePickerDialog.OnDateSetListener() {
@Override
public void onDateSet(DatePicker view, int year, int monthOfYear, int dayOfMonth) {
}
}, 2015, 02, 26).show();

: android: textColorPrimaryInverse Theme.AppCompat.Dialog