更改底部导航当前索引并从另一个屏幕更新 setState() class

Question

这是我的 bottom_bar 屏幕。我想从另一个屏幕按钮单击更改底部导航菜单。我该如何解决这个问题？是否有任何选项可以从另一个 class 导航 bottom_navigation。我没有通过搜索得到任何准确的答案。 [N.B：我是 flutter 的新手。如果有任何类型的误解，请原谅我]

  @override
  Widget build(BuildContext context) {
    final themeNotifier = Provider.of<ThemeNotifier>(context);
    return  Scaffold(
          key: _scaffoldKey,
          appBar: AppBar(
            title: const Text('JoyList'),
            leading: IconButton(
              icon:  Image( image: new AssetImage("images/Logo.png"),
                width:  200,
                height: 200,
                color: null,
                fit: BoxFit.scaleDown,
                alignment: Alignment.center,
              ),
              tooltip: 'Show Snackbar',
              onPressed: () {
                // scaffoldKey.currentState.showSnackBar(snackBar);
              },
            ),
            actions: <Widget>[
              IconButton(
                icon: const ImageIcon( AssetImage("images/ic_notification_default.png")),
                tooltip: 'Show Snackbar',
                onPressed: () {
                  // scaffoldKey.currentState.showSnackBar(snackBar);
                },
              ),
              FutureBuilder(
                  future: _apiProvider.getUserImageUrl(),
                  builder: (context, AsyncSnapshot<String> projectSnap) {
                    if(projectSnap.hasData){
                      var url = projectSnap.data;
                      return   IconButton(
                        icon: Center(
                          child: new Container(
                            width: 30,
                            height: 30,
                            decoration: new BoxDecoration(
                                shape: BoxShape.circle,
                                image: new DecorationImage(
                                    fit: BoxFit.cover,
                                    image: new NetworkImage(
                                        '$url'
                                    )
                                )
                            ),
                          ),
                        ),
                        onPressed: _modalBottomSheetMenu,

                      );
                    }else{
                      return Text("Nil");
                    }

                  }
              )
            ],
          ),
          body: CustomNavigator(
            navigatorKey: navigatorKey,
            home: Center(
              child: _widgetOptions.elementAt(selectedIndex),
            ),
            //Specify your page route [PageRoutes.materialPageRoute] or [PageRoutes.cupertinoPageRoute]
            pageRoute: PageRoutes.cupertinoPageRoute,
          ),
          bottomNavigationBar: new Theme(
            data: Theme.of(context).copyWith(
              // sets the background color of the `BottomNavigationBar`
                canvasColor: Theme.of(context).bottomAppBarColor,
                // sets the active color of the `BottomNavigationBar` if `Brightness` is light
                textTheme: Theme
                    .of(context)
                    .textTheme
                    .copyWith(caption: new TextStyle(color: Colors.yellow))),
         // sets the inactive color of the `BottomNavigationBar`
            child: new BottomNavigationBar(
              type: BottomNavigationBarType.fixed,
              currentIndex: selectedIndex,
              items: [
                BottomNavigationBarItem(
                  icon: selectedIndex==0? new ImageIcon( AssetImage('images/ic_home_selected.png')):new ImageIcon( AssetImage('images/ic_home_default.png')),
                  title: Text(''),
                ),
                BottomNavigationBarItem(
                  icon: selectedIndex==1? new ImageIcon( AssetImage('images/ic_list_selected.png')):new ImageIcon( AssetImage('images/ic_list_default.png')),
                  title: Text(''),
                ),
                BottomNavigationBarItem(
                  icon: ImageIcon( AssetImage("images/ic_additems.png")),
                  title: Text(''),
                ),
                BottomNavigationBarItem(
                  icon: ImageIcon( AssetImage("images/ic_search.png")),
                  title: Text(''),
                ),
                BottomNavigationBarItem(
                  icon: selectedIndex==4? new ImageIcon( AssetImage('images/ic_notification_selected.png')):new ImageIcon( AssetImage('images/ic_notification_default.png')),
                  title: Text(''),
                ),
                BottomNavigationBarItem(
                  //  icon: ImageIcon( AssetImage("images/ic_friends_selected.png")),
                  icon: ImageIcon( AssetImage("images/ic_friends_selected.png")),
                  title: Text(''),
                ),
              ],

              showSelectedLabels: false,
              unselectedItemColor: Theme.of(context).iconTheme.color,
              showUnselectedLabels: false,
              selectedItemColor: HexColor("1CD0A8"),
              onTap: _onItemTapped,
            ),
          )
      );

  }

我想在点击此处更改从另一个屏幕选择的底部栏索引。

child:   GestureDetector(
                    child: FutureBuilder(
                        future: _getUser(),
                        builder: (context, AsyncSnapshot<dynamic> projectSnap) {
                          if(projectSnap.hasData){
                            user = projectSnap.data;
                            var url = getProfileImageBaseUrl()+ user.profilePicture;
                            return  Column(
                              children: <Widget>[
                                Container(
                                  width: 170,
                                  height: 170,
                                  decoration: new BoxDecoration(
                                      color: Theme.of(context).cardColor,
                                      shape: BoxShape.circle,
                                      image: new DecorationImage(
                                          fit: BoxFit.cover,
                                          image: new NetworkImage(
                                              '$url'
                                          )
                                      )
                                  ),
                                ),
                                Center(
                                  child: Padding(
                                    padding: EdgeInsets.all(8.0),

                                    child: Text(user.fullName+"'s List",style: TextStyle(
                                        color: Theme.of(context).textTheme.caption.color,
                                        fontSize: 26
                                    ),),
                                  ),
                                )

                              ],
                            );
                          }else{
                            return Text("Nil");
                          }

                        }
                    ),
                    onTap: (){
                      print("On tap called");

                      Navigator.of(context)
                          .push(MaterialPageRoute(builder: (context) => FriendsPage()));
                    },
                  )

Answer 1

您可以为此使用 MobX，您需要用 Observer 包装您的 BottomNavigationBar 并在 MobX 商店中声明您的 selectedIndex。

一旦您的 MobX 商店中有了 selectedIndex，您就可以使用 Provider 在应用程序中的任何位置访问它。

更改底部导航当前索引并从另一个屏幕更新 setState() class

Change bottom navigation current index and update setState() from another screen class

android

ios

flutter

bottomnavigationview