Let an object move with AnimatedPositioned

Question

I asked this question in this link Transition with futter move object

how i can make movig an object with AnimatedPositioned ? if i want an object move with a value = 1, or a value = 10

or something like that:

i = 0;
i++;

or

i = 0;

i = i + 10;

how i can do that with AnimatedPositioned

Answer 1

You only need to update position value from your AnimatedPositioned:

AnimatedPositioned(
            width: selected ? 200.0 : 50.0,
            height: selected ? 50.0 : 200.0,
            top: selected ? 50.0 : 150.0,
            duration: const Duration(seconds: 2),
            curve: Curves.fastOutSlowIn,
            child: GestureDetector(
              onTap: () {
                setState(() {
                  selected = !selected;
                });
              },
              child: Container(
                color: Colors.blue,
                child: const Center(child: Text('Tap me')),
              ),
            ),
          )

Just change that values to yours.

Full example:

import 'package:flutter/material.dart';

void main() => runApp(const MyApp());

class MyApp extends StatelessWidget {
  const MyApp({Key? key}) : super(key: key);

  static const String _title = 'Flutter Code Sample';

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: _title,
      home: Scaffold(
        appBar: AppBar(title: const Text(_title)),
        body: const Center(
          child: MyStatefulWidget(),
        ),
      ),
    );
  }
}

class MyStatefulWidget extends StatefulWidget {
  const MyStatefulWidget({Key? key}) : super(key: key);

  @override
  State<MyStatefulWidget> createState() => _MyStatefulWidgetState();
}

class _MyStatefulWidgetState extends State<MyStatefulWidget> {
  bool selected = false;

  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: 200,
      height: 350,
      child: Stack(
        children: <Widget>[
          AnimatedPositioned(
            width: selected ? 200.0 : 50.0,
            height: selected ? 50.0 : 200.0,
            top: selected ? 50.0 : 150.0,
            duration: const Duration(seconds: 2),
            curve: Curves.fastOutSlowIn,
            child: GestureDetector(
              onTap: () {
                setState(() {
                  selected = !selected;
                });
              },
              child: Container(
                color: Colors.blue,
                child: const Center(child: Text('Tap me')),
              ),
            ),
          ),
        ],
      ),
    );
  }
}

Info: https://api.flutter.dev/flutter/widgets/AnimatedPositioned-class.html