flutter - FlatButton onPressed 在定位小部件中不起作用

Question

每当我在 Positioned Widget 中使用 FlatButton onPressed 方法时都不起作用。

我正在设计一个屏幕，按钮总是在屏幕底部，单击该按钮我们可以移动到其他屏幕，但这里不起作用，任何人都可以检查并帮助我。提前谢谢

           child: Stack(
               // height: MediaQuery.of(context).size.height,
               children: <Widget>[
                     Positioned(
                         left: 0,
                         bottom: 0,
                           // alignment: Alignment(0, 0),
                           child: Row(
                             mainAxisSize: MainAxisSize.max,
                             crossAxisAlignment: CrossAxisAlignment.end,
                             mainAxisAlignment: MainAxisAlignment.end,
                             children: <Widget>[
                               SizedBox(height: 115),
                               ButtonTheme(
                                 minWidth:
                                     MediaQuery.of(context).size.width / 2,
                                 height: 60.0,
                                 child: FlatButton.icon(
                                   icon: Icon(FontAwesomeIcons.fileInvoice),
                                   color: Colors.white,
                                   onPressed: () {
                                  MaterialPageRoute(builder: (context) => MainScreen());
                                   },
                                   label: Text(
                                     "My Orders",
                                     textAlign: TextAlign.center,
                                     style: TextStyle(
                                       // decoration: TextDecoration.underline,
                                       fontSize: 25,
                                       fontWeight: FontWeight.bold,
                                       color: Theme.of(context).accentColor,
                                     ),
                                   ),
                                 ),
                               ),
                               SizedBox(height: 115),
                               ButtonTheme(
                                 minWidth:
                                     MediaQuery.of(context).size.width / 2,
                                 height: 60.0,
                                 child: FlatButton.icon(
                                   icon: Icon(FontAwesomeIcons.dollarSign),
                                   color: Colors.white60,
                                   onPressed: () {
                                    Navigator.pushReplacementNamed(
                                       context, '/home');
                                   },
                                   label: Text(
                                     "Bean Balnace",
                                     textAlign: TextAlign.center,
                                     style: TextStyle(
                                       // decoration: TextDecoration.underline,
                                       fontWeight: FontWeight.bold,
                                       fontSize: 20,
                                       color: Theme.of(context).accentColor,
                                     ),
                                   ),
                                 ),
                               ),
                             ],
                           )),

Answer 1

改变这一行:

MaterialPageRoute(builder: (context) => MainScreen());

为此:

Navigator.push(context, MaterialPageRoute(builder: (context) => MainScreen()));