我想模糊一个
BottomNavigationBar
的Scaffold
的背景,这样它就可以给后面的项目带来很酷的模糊效果。我怎样才能做到这一点?
更多信息:我尝试通过为
canvasColor
创建一个新主题来为BottomNaviagtionBar
添加不透明度。这是我的代码:
bottomNavigationBar: new Theme(
data: Theme.of(context).copyWith(
canvasColor: Color(0xff424242).withOpacity(0.5),
),
child: new BottomNavigationBar(
onTap: navigationTapped,
currentIndex: _page,
items: [
new BottomNavigationBarItem(
icon: new Icon(Icons.home),
title: new Text('Home')
),
new BottomNavigationBarItem(
icon: new Icon(Icons.dashboard),
title: new Text('Menu')
),
new BottomNavigationBarItem(
icon: new Icon(Icons.date_range),
title: new Text('Dates')
),
],
),
)
这是我得到的输出:
令人惊讶的是,正如您所看到的,不透明度根本没有应用。我实际上不希望
BottomNavigationBar
变得不透明。我希望它是模糊的,这样它后面的内容就可以在BottomNaviagtionBar
上看到模糊的。我也尝试过将 BottomNavigationBar
包裹在 ImageFilter.blur()
内,但这也不起作用。
为此,我必须将底部导航与屏幕的其他内容放在一个堆栈中。我使用了 ClipRect、BackdropFilter 和 Opacity 的组合。这是有效的解决方案:
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: _buildAppBar(context),
body: Stack(
//these are the screens that will be loaded for every bottom nav item
children: <Widget>[
IndexedStack(
index: _currentTab,
children: _pages,
),
_buildBottomNavigation()
],
),
);
}
Widget _buildBottomNavigation() => Align(
alignment: FractionalOffset.bottomCenter,
//this is very important, without it the whole screen will be blurred
child: ClipRect(
//I'm using BackdropFilter for the blurring effect
child: BackdropFilter(
filter: ImageFilter.blur(
sigmaX: 10.0,
sigmaY: 10.0,
),
child: Opacity(
//you can change the opacity to whatever suits you best
opacity: 0.8,
child: BottomNavigationBar(
currentIndex: _currentTab,
onTap: (int index) {
setState(() {
_currentTab = index;
});
},
type: BottomNavigationBarType.fixed,
unselectedItemColor: AppColors.colorBlack,
items: allRoutes.map((NavigationRoute route) {
return _buildBottomNavigationBarItem(route);
}).toList(),
),
),
),
),
);
您可以用 Backdropfilter 包裹 BottomNavigationBar,然后用 ClipRRect 包裹所有内容。最后但并非最不重要的一点是将 Scaffold 属性 extendsBody 设置为 true,
bottomNavigationBar: ClipRRect(
child: BackdropFilter(
filter: ImageFilter.blur(sigmaX: 3, sigmaY: 3),
child: BottomNavigationBar(
YOUR CODE HERE
** just set a transparent backgroundColor .**
@override
Widget build(BuildContext context) {
return CupertinoPageScaffold(
navigationBar: CupertinoNavigationBar(
backgroundColor: Colors.transparent,
border: Border.all(
width: 0.0,
style: BorderStyle.none,
),
),
child: Column(
children: <Widget>[
Row(
children: <Widget>[
Expanded(
child: Container(
padding: EdgeInsets.only(
left: 20.0,
top: 0.0,
right: 20.0,
),
height: 280.0,
decoration: BoxDecoration(
gradient: LinearGradient(
colors: Const.color.linearColors,
),
// image: DecorationImage(
// image: AssetImage('assets/image/bac.png'),
// ),
),
child: Row(
children: <Widget>[Text('Hello')],
),
),
),
/// end of Expanded
],
),
],
),
);