Flutter实战小案例

(实战)点不到的按钮

// 主要实现效果类 class _MyHomePageState extends State<MyHomePage> {   // 1.定义要使用的变量   double btnLeft = 0;   double btnTop = 0;   int timeDuration = 500;   String textButton = "点我呀";   // 2.获得当前设备屏幕尺⼨，需要import 'dart:ui'   var s = window.physicalSize / window.devicePixelRatio;   // 3.新建⼀个随机对象，import 'dart:math';   var rng = new Random()   // 4.初始化init变量的值     @override   void initState() {     randomPosition();     super.initState();   }   // 5.随机变化left和top的值   randomPosition() {     setState(() {       btnLeft = rng.nextDouble() * (s.width - 100);       btnTop = rng.nextDouble() * (s.height - 40);     });   }  // 6.widgets渲染   @override   Widget build(BuildContext context) {     return Stack(       children: [         AnimatedPositioned(             duration: Duration(milliseconds: timeDuration),             left: btnLeft,             top: btnTop,             width: 100,             height: 40,             child: ElevatedButton(               onPressed: randomPosition,               child: Text(textButton),             ))       ],     );   } } 

（实战）点不到的按钮修改

• 修改按钮的宽200和⾼80
• 设置背景⾊ rgb 值为 136, 138, 226
• 按钮文本颜⾊设置为黑⾊
• 文本设置为：初次见面

class MyHomePage extends StatefulWidget {   const MyHomePage({Key? key, required this.title}) : super(key: key);   final String title;    @override   State<MyHomePage> createState() => _MyHomePageState(); }  class _MyHomePageState extends State<MyHomePage> {   double btnLeft = 0;   double btnTop = 0;   int timeDuration = 500;   String textButton = "初次见面";   var s = window.physicalSize / window.devicePixelRatio;   var rng = Random();   // 创建背景颜色对象   var backColor = const BoxDecoration(color: Color.fromRGBO(136, 138, 226, 1));   @override   void initState() {     randomPosition();     super.initState();   }    randomPosition() {     setState(() {       btnLeft = Random().nextDouble() * (s.width - 100);       btnTop = Random().nextDouble() * (s.height - 40);     });   }    @override   Widget build(BuildContext context) {     return Container(       decoration: backColor,       child: Stack(         children: [           Positioned(               left: btnLeft,               top: btnTop,               width: 200,               height: 80,               child: ElevatedButton(                 onPressed: randomPosition,                 child: Text(                   textButton,                   // 修改文本颜色                   style: const TextStyle(                     color: Colors.black,                   ),                 ),               )),         ],       ),     );   } }