Mastering Flutter Animation: How to Create a Clap Animation in Flutter

Flutter is an open-source UI software development kit created by Google. It allows developers to build beautiful and high-performance applications for mobile, web, and desktop platforms using a single codebase. One of the powerful features of Flutter is its animation framework, which enables developers to create stunning and interactive animations easily.

In this tutorial, we will learn how to create a clap animation similar to the one used in Medium's clapping feature. We will use Flutter's animation and gesture APIs to achieve this effect.

Understanding the Clap Animation

Before we dive into the implementation, let's understand how the clap animation works. When a user taps on the clap button, the button animates by scaling up and changing its color. Additionally, a small burst animation appears around the button to provide visual feedback.

Implementation Steps

Step 1: Setting up the Project

To get started, make sure you have Flutter installed on your machine. If not, head over to the official Flutter website and follow the installation instructions for your operating system.

Create a new Flutter project using the following command:

flutter create clap_animation

Navigate into the project directory:

cd clap_animation

Step 2: Creating the Clap Button

Let's start by creating the clap button. In Flutter, we can use the GestureDetector widget to detect tap events. Wrap the button widget with the GestureDetector and provide a callback function to handle the tap event.

import 'package:flutter/material.dart';

class ClapButton extends StatelessWidget {
  final VoidCallback onPressed;

  ClapButton({required this.onPressed});

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: onPressed,
      child: Container(
        width: 48,
        height: 48,
        decoration: BoxDecoration(
          shape: BoxShape.circle,
          color: Colors.blue,
        ),
        child: Icon(
          Icons.thumb_up,
          color: Colors.white,
        ),
      ),
    );
  }
}
  

In the code snippet above, we define a ClapButton widget that takes an onPressed callback as a parameter. This callback will be called when the button is tapped.

Step 3: Adding Animation

Now, let's add the animation to the clap button. We will use Flutter's AnimationController and Tween classes to animate the button's scale and color.

Add the following code to the ClapButton widget:

class ClapButton extends StatefulWidget {
  final VoidCallback onPressed;

  ClapButton({required this.onPressed});

  @override
  _ClapButtonState createState() => _ClapButtonState();
}

class _ClapButtonState extends State
    with SingleTickerProviderStateMixin {
  late AnimationController _animationController;
  late Animation _scaleAnimation;
  late Animation _colorAnimation;

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

    _animationController = AnimationController(
      vsync: this,
      duration: Duration(milliseconds: 300),
    );

    _scaleAnimation = Tween(begin: 1, end: 1.5).animate(
      CurvedAnimation(
        parent: _animationController,
        curve: Curves.easeInOut,
      ),
    );

    _colorAnimation = ColorTween(begin: Colors.blue, end: Colors.green)
        .animate(_animationController);
  }

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

  @override
  Widget build(BuildContext context) {
    return GestureDetector(
      onTap: () {
        _animationController.forward(from: 0);
        widget.onPressed();
      },
      child: AnimatedBuilder(
        animation: _animationController,
        builder: (context, child) {
          return Transform.scale(
            scale: _scaleAnimation.value,
            child: Container(
              width: 48,
              height: 48,
              decoration: BoxDecoration(
                shape: BoxShape.circle,
                color: _colorAnimation.value,
              ),
              child: Icon(
                Icons.thumb_up,
                color: Colors.white,
              ),
            ),
          );
        },
      ),
    );
  }
}
  

In the code above, we create an AnimationController with a duration of 300 milliseconds. We also define two animations: _scaleAnimation for scaling the button and _colorAnimation for changing its color. The animations are controlled by the _animationController.

Conclusion

In this tutorial, we have learned how to create a clap animation in Flutter. We started by setting up a new Flutter project and then implemented the clap button with the animation. By using Flutter's animation and gesture APIs, we achieved the desired effect.

Flutter provides a powerful and flexible animation framework, allowing developers to create impressive animations easily. With the knowledge gained from this tutorial, you can explore and create various other animations in your Flutter applications.