Flutter Animations: A Guide to Implicit and Explicit Animations

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Flutter offers powerful tools to add smooth and beautiful animations in your apps. Animations improve the user experience and make the UI more engaging.

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🧩 Types of Animations in Flutter

There are two main types:

1. Implicit Animations – Simple, automatic transitions

2. Explicit Animations – Fully controlled and customizable

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🔹 1. Implicit Animations

✅ What Are They?

Implicit animations automatically animate changes in widget properties like:

• Size

• Color

• Opacity

• Position

You don’t need to manage controllers or animation logic.

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🧠 How It Works

Flutter detects changes in values and smoothly transitions between them.

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📦 Common Implicit Animation Widgets

Widget	What It Animates
AnimatedContainer	Size, color, padding, etc.
AnimatedOpacity	Opacity (fade in/out)
AnimatedAlign	Alignment
AnimatedPositioned	Position inside a Stack
AnimatedDefaultTextStyle	Text styling

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✏️ Example: AnimatedContainer

class MyBox extends StatefulWidget {
  @override
  _MyBoxState createState() => _MyBoxState();
}

class _MyBoxState extends State<MyBox> {
  bool _big = false;

  @override
  Widget build(BuildContext context) {
    return Center(
      child: GestureDetector(
        onTap: () {
          setState(() {
            _big = !_big;
          });
        },
        child: AnimatedContainer(
          duration: Duration(seconds: 1),
          width: _big ? 200 : 100,
          height: _big ? 200 : 100,
          color: _big ? Colors.blue : Colors.red,
          curve: Curves.easeInOut,
        ),
      ),
    );
  }
}

➡️ Tapping the box smoothly changes its size and color.

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🔹 2. Explicit Animations

✅ What Are They?

Explicit animations give you full control over the animation, including:

• Start and stop

• Duration and curve

• Repeating and reversing

You use AnimationController, Tween, and AnimationBuilder.

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🧠 Key Components

Part	Purpose
AnimationController	Controls the animation time
Tween	Defines the value range
Animation	Connects controller to widget
AnimatedBuilder	Rebuilds UI with animation changes

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✏️ Example: Using AnimationController

class MyAnimation extends StatefulWidget {
  @override
  _MyAnimationState createState() => _MyAnimationState();
}

class _MyAnimationState extends State<MyAnimation>
    with SingleTickerProviderStateMixin {
  late AnimationController _controller;
  late Animation<double> _animation;

  @override
  void initState() {
    super.initState();

    _controller = AnimationController(
      vsync: this,
      duration: Duration(seconds: 2),
    );

    _animation = Tween<double>(begin: 0, end: 300).animate(_controller);

    _controller.forward();
  }

  @override
  Widget build(BuildContext context) {
    return AnimatedBuilder(
      animation: _animation,
      builder: (context, child) {
        return Container(
          width: _animation.value,
          height: 100,
          color: Colors.green,
        );
      },
    );
  }

  @override
  void dispose() {
    _controller.dispose();
    super.dispose();
  }
}

➡️ The box grows from 0 to 300 pixels smoothly over 2 seconds.

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🔄 Implicit vs Explicit: Comparison

Feature	Implicit Animation	Explicit Animation
Setup	Very easy	More setup required
Control	Limited	Full control (start, stop, etc.)
Use Case	Simple UI transitions	Complex, custom animations
Common Widgets	AnimatedContainer, AnimatedOpacity	AnimationController, Tween

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🔁 Bonus: AnimatedSwitcher (Implicit + Magic!)

Use AnimatedSwitcher to switch between widgets with animation:

AnimatedSwitcher(
  duration: Duration(milliseconds: 500),
  child: _isOn
      ? Icon(Icons.lightbulb, key: ValueKey(1))
      : Icon(Icons.lightbulb_outline, key: ValueKey(2)),
)

➡️ Smoothly switches icons with a fade or scale effect.

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🎯 When to Use What?

You Want To…	Use This Type
Animate simple size or color change	Implicit
Create a custom animation sequence	Explicit
Control timing and direction	Explicit
Add basic fade/slide	Implicit or Switcher

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🔧 Tips for Flutter Animations

• Use Curves like Curves.easeInOut for natural movement

• Always dispose of your AnimationController

• Use TickerProviderStateMixin for animations in StatefulWidget

• Test performance on real devices (animations may lag in emulators)

• Start small — build step by step

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📚 Useful Widgets for Animation

Widget	Description
AnimatedCrossFade	Fades between two child widgets
FadeTransition	Fade using controller
ScaleTransition	Scale in/out
SlideTransition	Move widget across screen
Hero	Animate between screens

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🧠 Summary

Term	Meaning
Implicit Animation	Auto animation on property change
Explicit Animation	Full control with controller and tween
Tween	Defines the value range
Controller	Manages animation flow
AnimatedBuilder	Rebuilds UI based on animation value

Learn  Flutter Training Course

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