How does Flutter handle animations?

Flutter provides a robust and flexible animation framework that enables developers to create smooth and engaging user interfaces. At its core, Flutter animations are built on the concept of implicit and explicit animations, giving developers the freedom to choose the level of control and complexity they need.

One of the key features is the use of widgets like `AnimatedContainer`, `AnimatedOpacity`, and `AnimatedBuilder`, which automatically animate changes in their properties, such as size, opacity, or any custom parameter. For instance, to animate the opacity of a widget, developers can use the `AnimatedOpacity` widget and specify the target opacity value along with a duration:

```dart
AnimatedOpacity(
  opacity: _isVisible ? 1.0 : 0.0,
  duration: Duration(milliseconds: 500),
  child: Container(
    // Your widget content
  ),
)
```

For more granular control, Flutter supports explicit animations through the `Tween` class and the `AnimationController`. This allows developers to define animation ranges and durations explicitly. For example, animating the position of a widget:

```dart
AnimationController controller = AnimationController(
  duration: Duration(seconds: 1),
  vsync: this,
);

Animation<Offset> offsetAnimation = Tween(
  begin: Offset(0.0, 0.0),
  end: Offset(1.0, 0.0),
).animate(controller);

// Trigger animation
controller.forward();
```

Developers can also create complex animations by combining multiple animations or utilizing physics-based animations with the `physics` property.

Flutter’s animation system is versatile, allowing for both simple and intricate animations. It provides a variety of pre-built widgets for common use cases and supports custom animations through explicit control, empowering developers to bring their app interfaces to life with engaging motion.