Make text box decorations affected by the current widget state

[hassony105]

Before:

TextBox(
  decoration: BoxDecoration(
    color: Colors.red,
  ),
  foregroundDecoration: BoxDecoration(
    color: Colors.blue,
  ),
),

After:

TextBox(
  decoration: WidgetStateProperty.all(BoxDecoration(
    color: Colors.red,
  )),
  foregroundDecoration: WidgetStateProperty.all(BoxDecoration(
    color: Colors.blue,
  )),
),

[bdlukaa]

Hello! Thank you for this pull request.

I like the idea of having a different decoration for different states, but the way you proposed is a bit limiting. It'd be nice to have it like buttons do: with a ButtonState.

TextBox(
  decoration: ButtonState.all(BoxDecoration(
    ...
  )),
)

[hassony105]

do you mean that you want me to replace these:

focusedDecoration
unFocusedDecoration

focusedForegroundDecoration
unFocusedForegroundDecoration

with ButtonState<BoxDecoration> decoration, ButtonState<BoxDecoration> foregroundDecoration ?

[bdlukaa]

yes! what do you think?

[hassony105]

OK, It is a pretty idea. I will do it.