Flutter中的浮动按钮FloatingActionButton 及融合底部工具栏

时间：2019-07-23 10:09:59 收藏：0 阅读：1192

FloatingActionButton 简称 FAB ,可以实现浮动按钮，也可以实现类似闲鱼 app 的底部凸起导航。

常用属性

FloatingActionButton的常用属性，同flutter中其他按钮的常用属性大部分相同，但是也有特殊的：

child ：子视图，一般为 Icon，不推荐使用文字
tooltip FAB：被长按时显示，也是无障碍功能
backgroundColor：背景颜色
elevation ：未点击的时候的阴影
hignlightElevation ：点击时阴影值，默认 12.0
onPressed ：点击事件回调
shape ：可以定义 FAB 的形状等
mini：是否是 mini 类型默认 false

import ‘package:flutter/material.dart‘;

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

class MyApp extends StatelessWidget{
  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home:HomeContent(), 
    );
  }
}

class HomeContent extends StatelessWidget{
   int _counter = 0; //声明计数器 

   void _incrementCounter(){
    setState(() { _counter++; });
  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
       appBar: AppBar(
          title:Text("flutter demo")
       ),
       body: Center(
         child: Column(
           mainAxisAlignment: MainAxisAlignment.center,
           children: <Widget>[
             Text(‘点一次增加一个数字‘),
             Text(
               ‘$_counter‘,
               style: Theme.of(context).textTheme.display1,
             ),
           ],
         ),
       ),
       floatingActionButton: FloatingActionButton(
         onPressed: _incrementCounter,
         tooltip: ‘Increment‘,
         child: Icon(Icons.add),
       ),
    );
  }
}

FloatingActionButton与BottomAppBar的结合

技术分享图片

不规则的底部导航栏代码如下：

import ‘package:flutter/material.dart‘;


class MyApp extends StatefulWidget {
  @override
  MyAppState createState() => MyAppState();
}

class MyAppState extends State<MyApp>  {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      body: BottomAppBarDemo(), //不规则的底部导航
    );
  }
}

class BottomAppBarDemo extends StatefulWidget {
  _BottomAppBarDemoState createState() => _BottomAppBarDemoState();
}

class _BottomAppBarDemoState extends State<BottomAppBarDemo> {
  List<Widget> _eachView;
  int _index = 0;
  @override
  void initState() {
    _eachView = List();
    _eachView..add(EachView(‘Home‘))..add(EachView(‘User‘)); 
    super.initState();
  }
  
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      floatingActionButton: FloatingActionButton(  //浮动交互按钮
        onPressed: (){
          Navigator.of(context).push(MaterialPageRoute(builder: (BuildContext context) {
            return EachView(‘New Page‘);
          } ));
        },
        tooltip: ‘新建页‘, //长按提示
        backgroundColor:Colors.red, //背景颜色
        child:Icon(Icons.add,color: Colors.white,)
      ),
      floatingActionButtonLocation: FloatingActionButtonLocation.centerDocked, //融合底部工具栏
      bottomNavigationBar: BottomAppBar( //底部工具栏
        color: Colors.red,
        shape: CircularNotchedRectangle(), //圆形缺口
        child: Row(
          mainAxisSize: MainAxisSize.max,
          mainAxisAlignment:MainAxisAlignment.spaceAround ,
          children: <Widget>[
            IconButton(
              icon: Icon(Icons.home),
              color: Colors.white,
              onPressed: (){
                setState(() {
                  _index = 0; 
                });
              },
            ),
            IconButton(
              icon: Icon(Icons.airplay),
              color: Colors.white,
              onPressed: (){
                setState(() {
                  _index = 1; 
                });
              },
            ),
            
          ],
        ),
      ),
      body:_eachView[_index],
    );
  }
}

class EachView extends StatefulWidget {
  String _title;
  EachView(this._title);
  @override
  _EachViewState createState() => _EachViewState();
}

class _EachViewState extends State<EachView> {
  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: AppBar(title: Text(widget._title)),
      body: Center(
        child: Text(widget._title),
      ),
    );
  }
}

如果还是跳上次的子页，代码如下:

  void initState() {
    _eachView = List();
    _eachView
      // ..add(EachView(‘Home‘))
      // ..add(EachView(‘User‘)); 
      ..add(Contacts())
      ..add(Personal());
    super.initState();
  }

还要记得头部要import的子页

原文：https://www.cnblogs.com/joe235/p/11229815.html