Navigation

Navigator Navigation in Flutter, pages are managed as stack, last in first out. The last pushed in page is visible.

Navigator.push(context, MaterialPageRoute(builder:(BuildContext)=> NewPage()))

Navigator.push().then(value) will listen to value once the Navigator.pop(context,value) passed a value.

• When former page use push, the latter page will have back button on its Appbar. Use Widget WillPopScope to use back button in the appBar.
• When former page use pushReplacement, the former page is destroyed from the stack.

Navigation between Stacks:
Switch between different stacks can cause info loss on the page.

Tabs:
Wrap Scaffold with DefaultTabController, add TapBar(tabs:[]) in AppBar(bottom:). Next, create TabBarView(children:[]) in body and rendering pages(tab pages are embedded, there will not be a scaffold).

Routes:

• Named Routes(routes)
• onGenerateRoute
• onUnknownRoute in MaterialApp, add

routes: {
    '/admin': (BuildContext context) => ProductsAdminPage(),
    '/': (BuildContext context) => ProductsPage(_products,_addProduct,_deleteProduct),
    },
onGenerateRoute: (RouteSettings settings) {
    final List<String> pathElements = settings.name.split('/');
    if (pathElements[0] != '') {
        return null;
    }
    if (pathElements[1] == 'product') {
        final int index = int.parse(pathElements[2]);
        return MaterialPageRoute(
        builder: (BuildContext context) =>
            ProductPage(_products[index]['image'], _products[index]['title']),
        );
    }
    return null;
    }

Alert showDialog

showDialog(
    context: context,
    builder: (BuildContext context) {
        return AlertDialog(
        title: Text('R U SURE'),
        content: Text('this action cannot be undone'),
        actions: <Widget>[
            FlatButton(
            child: Text('DISCARD'),
            onPressed: () {
                Navigator.pop(context);
            },
            ),
            FlatButton(
            child: Text('CONTINUE'),
            onPressed: () {
                Navigator.pop(context);
                Navigator.pop(context, true);
            },
            )
        ],
        );
    });

Modal showModalBottomSheet