Description:

animated size and fade

animated_size_and_fade #
This allows you to:

Do a fade and size transition between two widgets.
Show and hide a widget, by resizing it vertically while fading.


Size and Fade #
The AnimatedSizeAndFade widget does a fade and size transition between a "new" widget and an "old"
widget previously set as a child. The "old" and the "new" children must have the same width, but can
have different heights, and you don't need to know their sizes in advance.
You can also define a duration and curve for both the fade and the size, separately.
Important: If the "new" child is the same widget type as the "old" child, but with different
parameters, then AnimatedSizeAndFade will NOT do a transition between them, since as far as
the framework is concerned, they are the same widget, and the existing widget can be updated with
the new parameters. To force the transition to occur, set a Key (typically a ValueKey
taking any widget data that would change the visual appearance of the widget) on each child widget
that you wish to be considered unique.
Example:
bool toggle=true;
Widget widget1 = ...;
Widget widget2 = ...;

AnimatedSizeAndFade(
child: toggle ? widget1 : widget2
);
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Show and Hide #
The AnimatedSizeAndFade.showHide constructor may be used to show/hide a widget, by resizing it
vertically while fading.
Example:
bool toggle=true;
Widget widget = ...;

AnimatedSizeAndFade.showHide(
show: toggle,
child: widget,
);
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How does it compare to other similar widgets? #


With AnimatedCrossFade you must keep both the firstChild and secondChild, which is not necessary
with AnimatedSizeAndFade.


With AnimatedSwitcher you may simply change its child, but then it only animates the fade, not
the size.


AnimatedContainer also doesn't work unless you know the size of the children in advance.



Note: See
the StackOverflow question
that prompted this widget development.

The Flutter packages I've authored:

async_redux
fast_immutable_collections
provider_for_redux
i18n_extension
align_positioned
network_to_file_image
image_pixels
matrix4_transform
back_button_interceptor
indexed_list_view
animated_size_and_fade
assorted_layout_widgets
weak_map

My Medium Articles:



Async Redux: Flutter’s non-boilerplate version of Redux (
versions:
Português)



i18n_extension (
versions:
Português)



Flutter: The Advanced Layout Rule Even Beginners Must Know (
versions: русский)


My article in the official Flutter documentation:

Understanding constraints

Marcelo Glasberg:
https://github.com/marcglasberg
https://twitter.com/glasbergmarcelo
https://stackoverflow.com/users/3411681/marcg
https://medium.com/@marcglasberg