如何在不更改AppBar的情况下更改TabBar的背景颜色？

您可以通过如下更改主题primaryColor来更改TabBar的颜色：

return MaterialApp(      theme: ThemeData(        brightness: Brightness.light,        primaryColor: Colors.pink[800], //Changing this will change the color of the TabBar        accentColor: Colors.cyan[600],      ),      home: DefaultTabController(        length: 3,        child: Scaffold(          appBar: AppBar( bottom: TabBar(   indicatorColor: Colors.lime,   tabs: [     Tab(icon: Icon(Icons.directions_car)),     Tab(icon: Icon(Icons.directions_transit)),     Tab(icon: Icon(Icons.directions_bike)),   ], ), title: Text('Tabs Demo'),          ),          body: TabBarView( children: [   Icon(Icons.directions_car),   Icon(Icons.directions_transit),   Icon(Icons.directions_bike), ],          ),        ),      ),    );

如果您不在AppBar中使用它，则可以将TabBar包裹在Material小部件中并设置color属性，如下所示：

class TabBarDemo extends StatelessWidget {  @override  Widget build(BuildContext context) {    return MaterialApp(      home: Scaffold(        appBar: AppBar(          title: Text('Tabs Demo'),        ),        body: DefaultTabController(          length: 3,          child: Column( children: <Widget>[   Container(     constraints: BoxConstraints(maxHeight: 150.0),     child: Material(       color: Colors.indigo,       child: TabBar(         tabs: [Tab(icon: Icon(Icons.directions_car)),Tab(icon: Icon(Icons.directions_transit)),Tab(icon: Icon(Icons.directions_bike)),         ],       ),     ),   ),   Expanded(     child: TabBarView(       children: [         Icon(Icons.directions_car),         Icon(Icons.directions_transit),         Icon(Icons.directions_bike),       ],     ),   ), ],          ),        ),      ),    );  }}