fix date_input not using dateFormat to parse

[lejard-h]

use the given dateFormat to decode the input value.

for the following format dd/mm/yy, the parser was inversing month and days, 08/12/2018 -> 12/08/2018

[nshahan]

@lejard-h Could you provide a minimal repro of the issue so we can see how the issue appears?

[lejard-h]

DateFormat format = DateFormat('dd/MM/y');

<material-datepicker [outputFormat]="format"></material-datepicker>

and try to select October 8 for example, after you will need to double click on input to open dialog, and the date will be August 10

[lejard-h]

This does not seem to handle every case, it works on my timezone but this is probably an intl issue.

if you take the following code

  final format = DateFormat('dd/MM/y');

  final str = '05/08/2018';
  final date = format.parseLoose(str);

  print(date);
  print(format.format(date));

it print 2018-08-05 00:00:00.000 and 05/08/2018 with Europe/Paris timezone

but with America/Denver

FormatException: Error parsing 05/08/2018, invalid hour value: 0. Expected value between 15 and 15. Date parsed as 2018-08-04 15:00:00.000. at package:intl/src/intl/date_format_helpers.dart 130:7

I will follow the bug to intl package

[cpelling]

Thanks for the PR. The general approach looks good, but I'd want to see a regression test before merging this. Left a couple of other comments also.

[cpelling]

While you're here, can you replace this .any() call with a regular for loop? This construction is pretty odd.

[cpelling]

Careful - this is the member variable date, not a local. We should define a local variable to avoid interfering with the state of the component.

Ideally this method would be static.

[lejard-h]

Yes I just had an issue about this, this should be fix now but I will do some renaming work to avoid it and make it static