Learn How to Animate Widget Position in Flutter 2023

6 min 59 sec

Table of Contents

• Introduction
• Setting up the Flutter project
• Creating the AnimatedPositioned widget
• Animating the widget position
• Complete Code Reference
• Conclusion
• FAQs

Introduction

Flutter is an open-source mobile application development framework created by Google. It allows you to build high-performance, cross-platform applications with a single codebase. In this tutorial, we will learn how to animate widget position in Flutter using the AnimatedPositioned widget.

Setting up the Flutter project

Before we begin, make sure you have Flutter installed on your machine. If you don't, you can follow the installation guide provided in the official Flutter documentation.

Once you have Flutter installed, create a new Flutter project using the following command:

flutter create animated_positioned_demo

Creating the AnimatedPositioned widget

The AnimatedPositioned widget is a Flutter widget that animates its position within its parent widget. To use the AnimatedPositioned widget, we need to first create a container widget with a fixed size that will act as the parent widget for our AnimatedPositioned widget.

Here's an example of how to create a container widget with a fixed size:

Container(
  height: 200.0,
  width: 200.0,
  color: Colors.blue,
  child: // Child widgets will go here
),

Next, we need to create our AnimatedPositioned widget and add it as a child to our container widget. Here's an example of how to create an AnimatedPositioned widget:

AnimatedPositioned(
  duration: Duration(milliseconds: 500),
  curve: Curves.easeInOut,
  top: 0.0,
  left: 0.0,
  child: // Child widgets will go here
),

In the code above, we've created an AnimatedPositioned widget with a duration of 500 milliseconds and an ease-in-out curve. We've also set the initial position of the widget to the top-left corner of the parent container by setting the top and left properties to 0.0.

Animating the widget position

To animate the position of our AnimatedPositioned widget, we need to change the values of its top and left properties. We can do this by wrapping our AnimatedPositioned widget in an AnimatedBuilder widget and updating the values of top and left in its builder function.

Here's an example of how to animate the position of our AnimatedPositioned widget:

class MyHomePage extends StatefulWidget {
  @override
  State createState() => _MyHomePageState();
}
class _MyHomePageState extends State {
  bool _isPositionedRight = false;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Animated Widget Position'),
      ),
      body: Center(
        child: Stack(
          children: [
            AnimatedPositioned(
              duration: Duration(seconds: 1),
              curve: Curves.easeInOut,
              left: _isPositionedRight ? 200.0 : 0.0,
              child: Container(
                width: 100.0,
                height: 100.0,
                color: Colors.blue,
              ),
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          setState(() {
            _isPositionedRight = !_isPositionedRight;
          });
        },
        child: Icon(Icons.play_arrow),
      ),
    );
  }
}

In the code above, we've created an AnimatedBuilder widget that takes an Animation object as its argument.

Complete Code for Reference

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
       
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

class MyHomePage extends StatefulWidget {
  @override
  State createState() => _MyHomePageState();
}

class _MyHomePageState extends State {
  bool _isPositionedRight = false;

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        title: Text('Animated Widget Position'),
      ),
      body: Center(
        child: Stack(
          children: [
            AnimatedPositioned(
              duration: Duration(seconds: 1),
              curve: Curves.easeInOut,
              left: _isPositionedRight ? 200.0 : 0.0,
              child: Container(
                width: 100.0,
                height: 100.0,
                color: Colors.blue,
              ),
            ),
          ],
        ),
      ),
      floatingActionButton: FloatingActionButton(
        onPressed: () {
          setState(() {
            _isPositionedRight = !_isPositionedRight;
          });
        },
        child: Icon(Icons.play_arrow),
      ),
    );
  }
}

Conclusion

In this tutorial, we've learned how to animate widget position in Flutter using the AnimatedPositioned widget. We've also learned how to wrap our AnimatedPositioned widget in an AnimatedBuilder widget to update its position using an animation.

By following the steps outlined in this tutorial, you should now be able to create animated widgets that change position within their parent widgets in your Flutter applications.

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