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Flutter 发布时间：2022-05-03 发布网站：大佬教程 code.js-code.com

大佬教程收集整理的这篇文章主要介绍了飞镖 – 颤动 – 浮动动作按钮 – 隐藏物品的可见性，大佬教程大佬觉得挺不错的，现在分享给大家，也给大家做个参考。

我试图控制FAB中较小项目的可见性,根据下面的gif：

但是我无法在项目中插入不透明度.在任何地方我都会发生某种错误.我不知道不透明度是否是最好的方法.

要隐藏我相信动画的项目,可以控制它们出现的时间.

以下是我迄今取得的成就：

你能帮我解决这个问题吗？

以下是上面的gif代码：

import 'package:Flutter/animation.dart';
import 'package:Flutter/material.dart';

void main() {
  runApp(new MaterialApp(home: new HomePage()));
}

class HomePage extends StatefulWidget {
  @override
  HomePageState createState() => new HomePageState();
}

class HomePageState extends State<HomePage> with TickerProviderStatemixin {
  int _angle = 90;
  bool _isRotated = true;

  void _rotate(){
    setState((){
      if(_isRotated) {
        _angle = 45;
        _isRotated = false;
      } else {
        _angle = 90;
        _isRotated = true;
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      body: new Stack(
        children: <Widget>[
            new Positioned(
              bottom: 200.0,right: 24.0,child: new Container(
                child: new Row(
                  children: <Widget>[
                    new Container(
                      margin: new EdgeInsets.only(right: 16.0),child: new Text(
                        'foo1',style: new TextStyle(
                          fontSize: 13.0,fontFamily: 'Roboto',color: new Color(0xFF9E9E9E),fontWeight: FontWeight.bold,),new Material(
                      color: new Color(0xFF9E9E9E),type: MaterialType.circle,elevation: 6.0,child: new GestureDetector(
                        child: new Container(
                          width: 40.0,height: 40.0,child: new InkWell(
                            onTap: (){},child: new Center(
                              child: new Icon(
                                Icons.add,color: new Color(0xFFFFFFFF),)
                        ),)
                    ),],)
            ),new Positioned(
            bottom: 144.0,child: new Container(
              child: new Row(
                children: <Widget>[
                  new Container(
                    margin: new EdgeInsets.only(right: 16.0),child: new Text(
                      'foo2',style: new TextStyle(
                        fontSize: 13.0,new Material(
                    color: new Color(0xFF00BFA5),child: new GestureDetector(
                      child: new Container(
                        width: 40.0,child: new InkWell(
                          onTap: (){},child: new Center(
                            child: new Icon(
                              Icons.add,)
                      ),)
                  ),)
          ),new Positioned(
            bottom: 88.0,child: new Text(
                      'foo3',new Material(
                    color: new Color(0xFFE57373),new Positioned(
            bottom: 16.0,right: 16.0,child: new Material(
              color: new Color(0xFFE57373),child: new GestureDetector(
                child: new Container(
                  width: 56.0,height: 56.00,child: new InkWell(
                    onTap: _rotate,child: new Center(
                      child: new RotationTransition(
                        turns: new AlwaysStoppedAnimation(_angle / 360),child: new Icon(
                          Icons.add,)
                ),]
      )
    );
  }
}

解决方法

我使用了Opacity,但在使用ScaleTransition后它变得多余了.使用ScaleTransition,可以隐藏和显示小部件.

我使用3个动画来生成级联效果.

以下是代码及其结果：

import 'package:Flutter/animation.dart';
import 'package:Flutter/material.dart';

void main() {
  runApp(new MaterialApp(home: new HomePage()));
}

class HomePage extends StatefulWidget {
  @override
  HomePageState createState() => new HomePageState();
}

class HomePageState extends State<HomePage> with TickerProviderStatemixin {
  int _angle = 90;
  bool _isRotated = true;

  AnimationController _controller;
  Animation<double> _animation;
  Animation<double> _animation2;
  Animation<double> _animation3;

  @override
  void initState() {
    _controller = new AnimationController(
      vsync: this,duration: const Duration(milliseconds: 180),);

    _animation = new CurvedAnimation(
      parent: _controller,curve: new Interval(0.0,1.0,curve: Curves.linear),);

    _animation2 = new CurvedAnimation(
      parent: _controller,curve: new Interval(0.5,);

    _animation3 = new CurvedAnimation(
      parent: _controller,curve: new Interval(0.8,);
    _controller.reverse();
    super.initState();
  }

  void _rotate(){
    setState((){
      if(_isRotated) {
        _angle = 45;
        _isRotated = false;
        _controller.forWARD();
      } else {
        _angle = 90;
        _isRotated = true;
        _controller.reverse();
      }
    });
  }

  @override
  Widget build(BuildContext context) {
    return new Scaffold(
      body: new Stack(
        children: <Widget>[
            new Positioned(
              bottom: 200.0,child: new Container(
                child: new Row(
                  children: <Widget>[
                    new ScaleTransition(
                      scale: _animation3,alignment: FractionalOffset.center,child: new Container(
                        margin: new EdgeInsets.only(right: 16.0),child: new Text(
                          'foo1',style: new TextStyle(
                            fontSize: 13.0,new ScaleTransition(
                      scale: _animation3,child: new Material(
                        color: new Color(0xFF9E9E9E),child: new GestureDetector(
                          child: new Container(
                            width: 40.0,child: new InkWell(
                              onTap: (){
                                if(_angle == 45.0){
                                  print("foo1");
                                }
                              },child: new Center(
                                child: new Icon(
                                  Icons.add,)
                          ),child: new Container(
              child: new Row(
                children: <Widget>[
                  new ScaleTransition(
                    scale: _animation2,child: new Container(
                      margin: new EdgeInsets.only(right: 16.0),child: new Text(
                        'foo2',new ScaleTransition(
                    scale: _animation2,child: new Material(
                      color: new Color(0xFF00BFA5),child: new InkWell(
                            onTap: (){
                              if(_angle == 45.0){
                                print("foo2");
                              }
                            },child: new Container(
              child: new Row(
                children: <Widget>[
                  new ScaleTransition(
                    scale: _animation,child: new Text(
                        'foo3',new ScaleTransition(
                    scale: _animation,child: new Material(
                      color: new Color(0xFFE57373),child: new InkWell(
                            onTap: (){
                              if(_angle == 45.0){
                                print("foo3");
                              }
                            },]
      )
    );
  }
}