AnimatedCrossFade

The AnimatedCrossFade widget in Dart is a very useful tool for implementing crossfading animations in your application. This widget automatically animates the opacity and size of two children widgets as they are swapped out.

How it works

When you use the AnimatedCrossFade widget, you need to provide two children widgets, one that is currently visible, and one that will become visible. You also specify a duration for the animation, and a crossFadeState that specifies whether the widget is currently showing the first or second child.

When the state of the crossFadeState changes, the AnimatedCrossFade widget will automatically animate the opacity and size transitions between the two children.

Properties

- alignment (AlignmentGeometry)

The alignment of the crossfade animation. Defaults to Alignment.topCenter.

- duration (Duration)

The duration of the crossfade animation.

- firstChild (Widget)

The first widget child to display during crossfade animations.

- secondChild (Widget)

The second widget child to display during crossfade animations.

- crossFadeState (CrossFadeState)

The current state of the crossfade animation.

- layoutBuilder (AnimatedCrossFadeBuilder)

The builder function for creating the layout of the AnimatedCrossFade.

Example

Here's an example of using the AnimatedCrossFade widget in a simple app that shows two images with crossfading animation.

AnimatedCrossFade(
  duration: const Duration(milliseconds: 500),
  firstChild: Image.network(
      'https://flutter.github.io/assets-for-api-docs/assets/widgets/owl-2.jpg',
      fit: BoxFit.cover,
  ),
  secondChild: Image.network(
      'https://flutter.github.io/assets-for-api-docs/assets/widgets/owl.jpg',
      fit: BoxFit.cover,
  ),
  crossFadeState:
      _first ? CrossFadeState.showFirst : CrossFadeState.showSecond,
)

Conclusion

The AnimatedCrossFade widget in Dart is a great tool for implementing crossfading transitions in your app. With a few properties and some children widgets, you can easily create smooth animation effects that will delight your users.