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NestedNavigators

Flutter widget for implementing multiple nested navigators with their own route stacks.

Usage

To use, you must at least specify two arguments items and generateRoute:

class RootPage extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _RootPageState();
}

class _RootPageState extends State<RootPage> {
  @override
  Widget build(BuildContext context) {
    return NestedNavigators(
      items: {
        NestedNavItemKey.blue: NestedNavigatorItem(
          initialRoute: Routes.blue,
          icon: Icons.access_time,
          text: "Blue",
        ),
        NestedNavItemKey.red: NestedNavigatorItem(
          initialRoute: Routes.red,
          icon: Icons.send,
          text: "Red",
        ),
        NestedNavItemKey.green: NestedNavigatorItem(
          initialRoute: Routes.green,
          icon: Icons.perm_identity,
          text: "Green",
        ),
      },
      generateRoute: Routes.generateRoute,
    );
  }
}

See Routes.generateRoute()

By default NestedNavigators displays BottomNavigationBar, but you can hide it if you want:

clearStackAfterTapOnCurrentTab: false

You can customize BottomNavigatosBar items in two ways:

• configure BottomNavigationBarItem:

buildBottomNavigationItem: (key, item, selected) => BottomNavigationBarItem(
           icon: Icon(
             item.icon,
             color: Colors.blue,
           ),
           title: Text(
             item.text,
             style: TextStyle(fontSize: 20),
           ),
         )

• Define your own widget:

buildCustomBottomNavigationItem: (key, item, selected) => Container(
            height: 60,
            child: Column(
              mainAxisAlignment: MainAxisAlignment.center,
              mainAxisSize: MainAxisSize.min,
              children: <Widget>[
                Icon(
                  item.icon,
                  size: 24,
                  color: selected ? Colors.blue : null,
                ),
                Text(
                  item.text,
                  style: TextStyle(fontSize: 20, color: selected ? Colors.blue : null),
                ),
              ],
            ),
          )

Initial selected navigator:

• If number of navigators is even number, than it will be the first elemnt of items;
• If number of navigators is odd number, than it will be the middle element of items;
• You can specify your navigator key:

 initialNavigatorKey: NestedNavItemKey.green

You can specify the color of ripple effect in your app theme or in bottomNavigationBarTheme:

bottomNavigationBarTheme: Theme.of(context).copyWith(
       splashColor: Colors.blue[100],
   )

By default, if a user clicks on an already selected tab item, the route stack will be cleared and the initial route will be displayed. You can disable this option:

clearStackAfterTapOnCurrentTab: false

When you navigate to another route within nested navigator, you can hide BottomNavigatorsBar for specific route, just add hideNavTabBar: true to route arguments:

Navigator.of(context).pushNamed(
                    Routes.red,
                    arguments: {
                      hideNavTabBar: true,
                    },
                  );

You can select another navigator from your routes:

NestedNavigatorsBlocProvider.of(context).select(NestedNavItemKey.green)

You can also switch displayed navigator and at the same time make navigation in the new navigator:

NestedNavigatorsBlocProvider.of(context).selectAndNavigate(
                      NestedNavItemKey.green,
                      (navigator) => navigator.pushNamed(
                            Routes.green,
                            arguments: {
                              ArgumentKeys.value: 100,
                            },
                          ));

Add NestedNavigatorsBlocProvider to app widget if you want to use the root navigator and need access to nested navigators from there:

class App extends StatefulWidget {
  @override
  State<StatefulWidget> createState() => _AppState();
}

class _AppState extends State<App> {
  final NestedNavigatorsBloc _bloc = NestedNavigatorsBloc<NestedNavItemKey>();

  @override
  Widget build(BuildContext context) {
    return NestedNavigatorsBlocProvider(
      bloc: _bloc,
      child: MaterialApp(
        title: 'Flutter Demo',
        home: RootPage(),
        onGenerateRoute: (routeSettings) => Routes.generateRoute(routeSettings),
      ),
    );
  }
}

You can use Drawer instead of BottomNavigationBar, use drawer or endDrawer for this:

drawer: (items, selectedItemKey, selectNavigator) => Drawer(
            child: ListView(
              children: items.entries
                  .map((entry) => ListTile(
                        title: Text(
                          entry.value.text,
                          style: TextStyle(
                            color: entry.key == selectedItemKey
                                ? Colors.blue
                                : null,
                          ),
                        ),
                        trailing: Icon(
                          entry.value.icon,
                          color:
                              entry.key == selectedItemKey ? Colors.blue : null,
                        ),
                        onTap: () => selectNavigator(entry.key),
                      ))
                  .toList(),
            ),
          ),

Also you can open drawers from your pages:

NestedNavigatorsBlocProvider.of(context).actionWithScaffold(
                  (scaffoldState) => scaffoldState.openDrawer(),
                );