AnimatedPositioned 位置变化的动画

AnimatedPositioned 位置变化的动画

import 'package:flutter/material.dart';

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

class MyApp extends StatelessWidget {
  // This widget is the root of your application.
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      title: 'Flutter Demo',
      theme: ThemeData(
        // This is the theme of your application.
        //
        // Try running your application with "flutter run". You'll see the
        // application has a blue toolbar. Then, without quitting the app, try
        // changing the primarySwatch below to Colors.green and then invoke
        // "hot reload" (press "r" in the console where you ran "flutter run",
        // or simply save your changes to "hot reload" in a Flutter IDE).
        // Notice that the counter didn't reset back to zero; the application
        // is not restarted.
        primarySwatch: Colors.blue,
      ),
      home: MyHomePage(),
    );
  }
}

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

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

class _MyHomePageState extends State<MyHomePage> {
  bool _showMessage = false;
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(
        actions: [
          TextButton(
            onPressed: () {
              setState(() {
                _showMessage = !_showMessage;
              });
            },
            child: Icon(
              Icons.add_location,
              //size: 36,
              color: Colors.white,
            ),
          ),
        ],
      ),
      body: Container(
        width: 300,
        height: 300,
        color: Colors.amber,
        child: Center(
          child: Stack(
            children: [
              Positioned(
                child: Text(
                  "data",
                  style: TextStyle(color: Colors.blue),
                ),
                bottom: 10,
                right: 10,
              ),
              AnimatedPositioned(
                child: Text("data"),
                duration: Duration(milliseconds: 500),
                right: 10,
                bottom: _showMessage ? 70 : 10,
                top: _showMessage ? 50 : 100,
              )
            ],
          ),
        ),
      ),
    );
  }
}