Use case

When using DatePickerDialog or InputDatePickerFormField in some Android devices(E.g. Samsung) slash symbol(/) is not available for TextInputType.datetime, therefore the only way to use DatePickerEntryMode.input mode is to use a different keyboardType which makes it less efficient.

Proposal

Add inputFormatters option which will allow developers to use something like mask_text_input_formatter to autocomplete slashes and improve the overall usability of the DatePickerEntryMode.input and DatePickerEntryMode.inputOnly modes.