I have three screens. A, B and C. I push A, B, and C by using the following code. A is the first screen of the app.
class FadeInSlideOutRoute<T> extends MaterialPageRoute<T> {
FadeInSlideOutRoute({WidgetBuilder builder, RouteSettings settings})
: super(builder: builder, settings: settings);
#override
Widget buildTransitions(BuildContext context,
Animation<double> animation,
Animation<double> secondaryAnimation,
Widget child) {
if (settings.isInitialRoute)
return child;
// Fades between routes. (If you don't want any animation,
// just return child.)
return new FadeTransition(opacity: animation, child: child);
}
}
Screen declare in build method.
#override
Widget build(BuildContext context) {
return new MaterialApp(
debugShowCheckedModeBanner: false,
theme: new ThemeData(
primarySwatch: Colors.blue,
),
onGenerateRoute: (RouteSettings settings) {
switch (settings.name) {
case '/B':
return new FadeInSlideOutRoute(
builder: (_) => new LoginScreen(),
settings: settings,
);
case '/C':
return new FadeInSlideOutRoute(
builder: (_) => new ForgotPasswordScreen(),
settings: settings,
);
}
assert(false);
},
home: _LandingScreen(),
);
}
Now, I'm calling the following method to push new screens.
Navigator.pushNamed(context, '/B');
After that
Navigator.pushNamed(context, '/C');
issue is
when I'm pressing back of Android device from screen C it's come to screen A directly. But it should on screen B. Please help guys.
Related
I had pushed a new Screen from my main screen and it had navigated smoothly and also showed the back button however now that I run the button, the default button is not showing in my code.
The only change that I made was that I changed the route in my main file from taskScreen() to task().
But this was essential as i wanted to make some more routes from my second screen and so it had to return a Material App.
How can i get the default back button back?
My code:
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
home: DefaultTabController(length: 2,child: MyHomePage(title: '')),
routes: <String, WidgetBuilder>{
"/TaskScreen": (BuildContext context) => new task(), //CHANGED HERE
},
);
}
}
class MyHomePage extends StatelessWidget {
MyHomePage({Key key, this.title}) : super(key: key);
#override
Widget build(BuildContext context){
return Scaffold(
appBar: AppBar(
..
),
body: ...
}
}
My second screen
class task extends StatelessWidget{
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Task',
home: new taskScreen(),
routes: <String, WidgetBuilder>{
"/Completed": (BuildContext context) => new Completed()
}
);
}
}
class taskScreen extends StatefulWidget{
#override
taskState createState() => new taskState();
}
class taskState extends State<taskScreen> {
#override
Widget build(BuildContext context) {
Column taskScreen = Column (...)
return Scaffold(
appBar: AppBar(
title: Text('Task Screen')),
body: taskScreen,
);
}
}
Class name must to start with uppercase character. You have wrong structure, MaterialApp must to be only one time.
https://dart.dev/guides/language/language-tour
For me it happened when I added a draw to all my various AppBars ... quick googling provided a solution which worked for me:
I added to the AppBar the following which let flutter take a conscious decision whether there is or is not what to go back to ...
automaticallyImplyLeading: true,
Then I added defined how the "leading" should look like (also to the appbar):
leading: IconButton(
icon: Icon(Icons.arrow_back),
onPressed: () => Navigator.pop(context, false),
),
Making a long story short: Adding the following to the respective AppBar did the work:
leading: IconButton(
icon: Icon(Icons.arrow_back),
onPressed: () => Navigator.pop(context, false),
),
Remove the second routes MaterialApp and replace it with an AppBar
In my App I have a bottom bar that is always visible. I found in this site that a good way to keep tabs in memory while also having multiple navigators is by using Offscreen. However, when I put a Navigator inside Offscreen none of its contents can receive focus. I made a very simple example that reproduces what I'm saying:
void main() async {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
MyApp({
Key key,
}) : super(key: key);
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
home: MyHomeScreen(),
);
}
}
class MyHomeScreen extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Container(
child: Scaffold(
body: Stack(
children: [
Offstage(
offstage:false,
child: Navigator(
onGenerateRoute: (RouteSettings settings) {
return MaterialPageRoute(
builder: (BuildContext context) {
return Center(child: TextField());
},
);
},
),
),
Offstage(
offstage:true,
child: Navigator(
onGenerateRoute: (RouteSettings settings) {
return MaterialPageRoute(
builder: (BuildContext context) {
return Center(child: TextField());
},
);
},
),
),
],
),
),
);
}
}
If you click on the TextField, it will not receive focus, so the user cannot type anything.
Is there any way to direct focus to the active (visible) offscreen ?
Any other suggestion for this problem?
Thanks
That is a current issue in Github. To solve it you need to put a FocusScope widget on top of each Navigator.
This comment in the GH thread has an example:
https://github.com/flutter/flutter/issues/17098#issuecomment-414610135
How do you navigate to a new screen in Flutter?
These questions are similar, but are asking more than I am.
Flutter - Navigate to a new screen, and clear all the previous screens
Flutter: How do I navigate to a new screen using DropDownMenuItems
Flutter: Move to a new screen without back
flutter navigation to new screen not working
I am adding an answer below.
Navigate to a new screen:
Navigator.of(context).push(MaterialPageRoute(builder: (context) => NewScreen()));
where context is the BuildContext of a widget and NewScreen is the name of the second widget layout.
Code
main.dart
import 'package:flutter/material.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(primarySwatch: Colors.blue),
home: HomeScreen(),
);
}
}
class HomeScreen extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('Home Screen')),
body: Center(
child: ElevatedButton(
child: const Text(
'Navigate to a new screen >>',
style: TextStyle(fontSize: 24.0),
),
onPressed: () {
_navigateToNextScreen(context);
},
),
),
);
}
void _navigateToNextScreen(BuildContext context) {
Navigator.of(context).push(MaterialPageRoute(builder: (context) => NewScreen()));
}
}
class NewScreen extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(title: const Text('New Screen')),
body: const Center(
child: Text(
'This is a new screen',
style: TextStyle(fontSize: 24.0),
),
),
);
}
}
See also
Documentation
Navigator and Routes and Transitions... Oh, My! - Simon Lightfoot | Flutter Europe
To load new screens with Flutter pre-canned animations, use their respective transition classes. For example:
Container Transformation
Basically we have the first widget or screen transform into the next screen. For this we need to use OpenContainer. The following code illustrates an item in a ListView transformed to its details page.
#override
Widget build(BuildContext context) {
return Card(
color: Colors.white,
elevation: 2.0,
child: OpenContainer(
transitionType: ContainerTransitionType.fadeThrough,
closedColor: Theme.of(context).cardColor,
closedElevation: 0.0,
openElevation: 4.0,
transitionDuration: Duration(milliseconds: 1500),
openBuilder: (BuildContext context, VoidCallback _) => THENEXTSCREEN(),
closedBuilder: (BuildContext _, VoidCallback openContainer) {
return ListTile(
leading: Icon(Icons.album),
title: Text("ITEM NAME"),
);
},
),
);
}
Shared Axis
This transition is similar to that in Tab or Stepper. We need SharedAxisTransition, PageTransitionSwitcher, along with a state to model transition between active and previous page. If we only switch between two pages we can use a simple boolean isFirstPage for it. Here's the snippet with Provider as state management:
#override
Widget build(BuildContext context) {
return Consumer<YourState>(
builder: (context, state, child) {
return PageTransitionSwitcher(
duration: const Duration(milliseconds: 1500),
reverse: !state.isFirstPage, // STATE
transitionBuilder: (
Widget child,
Animation<double> animation,
Animation<double> secondaryAnimation,
) {
return SharedAxisTransition(
child: child,
animation: animation,
secondaryAnimation: secondaryAnimation,
transitionType: SharedAxisTransitionType.horizontal,
);
},
child: state.isFirstPage? FIRSTPAGE() : SECONDPAGE(), // STATE
);
},
);
}
Note that in all these scenarios we don't use Navigator and MaterialPageRoute. All these codes are derived from animations repo so you may want to check it out first.
Navigate to next screen with back using Navigator.push()
Navigator.push(
context,
MaterialPageRoute(builder: (context) => SecondRoute()),);
Navigate to next screen without back using Navigator.pushReplacement()
Navigator.pushReplacement(
context,MaterialPageRoute(builder: (context) => SecondRoute()),);
onTap: () {
Navigator.push(context,
MaterialPageRoute(builder: (context) => NextScreenName()));
}
If you are familiar with web development this approach is similar to routing.
main.dart
void main() {
setupLocator();
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
routes: {
'/' : (BuildContext context)=>HomePage(),
'/register' : (BuildContext context)=>RegisterPage(),
},
);
}
}
You can add button onPressed event from the homepage.dart to navigate register.dart as follows.
onPressed: (){
Navigator.pushReplacementNamed(context, '/register');
},
Here is a full example of routes push / pop:
import 'package:flutter/material.dart';
void main() {
runApp(MyApp());
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Routes',
routes: {
'/login': (BuildContext context) => Login(),
// add another route here
// '/register': (BuildContext context) => Register(),
},
theme: ThemeData(
primarySwatch: Colors.blue,
visualDensity: VisualDensity.adaptivePlatformDensity,
),
home: MyHomePage(title: 'Flutter Routes'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(widget.title),
),
body: Center(
child: Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
RaisedButton(
onPressed: () {
// This gives the back button:
Navigator.of(context).pushNamed('/login');
// This doesn't give the back button (it replaces)
//Navigator.pushReplacementNamed(context, '/login');
},
child: Text('Login'),
),
],
),
),
);
}
}
class Login extends StatefulWidget {
#override
_LoginState createState() => _LoginState();
}
class _LoginState extends State<Login> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Login Page'),
),
body: Center(
child: RaisedButton(
onPressed: () {
// This will only work for pushNamed
Navigator.of(context).pop();
},
child: Text('Go back'),
),
));
}
}
you can use that way in your build widget
onTap: () { Navigator.of(context).push(MaterialPageRoute( builder: (context) => NewScreen()));},
In formal method :
Navigator.push(context, MaterialPageRoute(builder: (context)=>Second()));
In GetX method :
Get.to(Second());
If we can navigate screen into another page and delete current page from stack then we can use method which is define below :
Get.off(Third());
If we can navigate screen into another page and delete all route or page from stack then we can use the method which is define below :
Get.offAll(Third());
If we want to use Navigator.pop() then GetX give a Method which is define below :
Get.back();
You can try with the following code
Navigator.pushReplacement(context, MaterialPageRoute(builder: (context) => YourNextScreen())),
I found a good tutorial that I have followed along, it is very comprehensive with screenshots and step by step, you can also download the code and just run it. Very helpful for me learning Flutter especially I am totally a begineer.
https://medium.com/#misterflutter/lesson-5-creating-new-screens-f740994190c7
https://medium.com/#misterflutter/lesson-6-creating-new-screens-part-2-4997085a43af?sk=d2a0fb723af42b78800f7cf19b312b62
With the Get plugin, you can navigate to a new page by simply calling
Get.to(Page());
This way you can present the next screen
Navigator.of(context).push(
MaterialPageRoute(fullscreenDialog: true,
builder: (context) => const NewScreen(),
),
);
FloatingActionButton(
onPressed: (){
Navigator.of(context).push(MaterialPageRoute(builder: (context) => const AddUser()));
},
child: const Icon(Icons.add),
),
I've been searching around for a good navigation/router example for Flutter but I have not managed to find one.
What I want to achieve is very simple:
Persistent bottom navigation bar that highlights the current top level route
Named routes so I can navigate to any route from anywhere inside the app
Navigator.pop should always take me to the previous view I was in
The official Flutter demo for BottomNavigationBar achieves 1 but back button and routing dont't work. Same problem with PageView and TabView. There are many other tutorials that achieve 2 and 3 by implementing MaterialApp routes but none of them seem to have a persistent navigation bar.
Are there any examples of a navigation system that would satisfy all these requirements?
All of your 3 requirements can be achieved by using a custom Navigator.
The Flutter team did a video on this, and the article they followed is here: https://medium.com/flutter/getting-to-the-bottom-of-navigation-in-flutter-b3e440b9386
Basically, you will need to wrap the body of your Scaffold in a custom Navigator:
class _MainScreenState extends State<MainScreen> {
final _navigatorKey = GlobalKey<NavigatorState>();
// ...
#override
Widget build(BuildContext context) {
return Scaffold(
body: Navigator(
key: _navigatorKey,
initialRoute: '/',
onGenerateRoute: (RouteSettings settings) {
WidgetBuilder builder;
// Manage your route names here
switch (settings.name) {
case '/':
builder = (BuildContext context) => HomePage();
break;
case '/page1':
builder = (BuildContext context) => Page1();
break;
case '/page2':
builder = (BuildContext context) => Page2();
break;
default:
throw Exception('Invalid route: ${settings.name}');
}
// You can also return a PageRouteBuilder and
// define custom transitions between pages
return MaterialPageRoute(
builder: builder,
settings: settings,
);
},
),
bottomNavigationBar: _yourBottomNavigationBar,
);
}
}
Within your bottom navigation bar, to navigate to a new screen in the new custom Navigator, you just have to call this:
_navigatorKey.currentState.pushNamed('/yourRouteName');
To achieve the 3rd requirement, which is Navigator.pop taking you to the previous view, you will need to wrap the custom Navigator with a WillPopScope:
#override
Widget build(BuildContext context) {
return Scaffold(
body: WillPopScope(
onWillPop: () async {
if (_navigatorKey.currentState.canPop()) {
_navigatorKey.currentState.pop();
return false;
}
return true;
},
child: Navigator(
// ...
),
),
bottomNavigationBar: _yourBottomNavigationBar,
);
}
And that should be it! No need to manually handle pop or manage a custom history list.
CupertinoTabBar behave exactly same as you described, but in iOS style. It can be used in MaterialApps however.
Sample Code
What you are asking for would violate the material design specification.
On Android, the Back button does not navigate between bottom
navigation bar views.
A navigation drawer would give you 2 and 3, but not 1. It depends on what's more important to you.
You could try using LocalHistoryRoute. This achieves the effect you want:
class MainPage extends StatefulWidget {
#override
State createState() {
return new MainPageState();
}
}
class MainPageState extends State<MainPage> {
int _currentIndex = 0;
List<int> _history = [0];
#override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: new Text('Bottom Nav Back'),
),
body: new Center(
child: new Text('Page $_currentIndex'),
),
bottomNavigationBar: new BottomNavigationBar(
currentIndex: _currentIndex,
items: <BottomNavigationBarItem>[
new BottomNavigationBarItem(
icon: new Icon(Icons.touch_app),
title: new Text('keypad'),
),
new BottomNavigationBarItem(
icon: new Icon(Icons.assessment),
title: new Text('chart'),
),
new BottomNavigationBarItem(
icon: new Icon(Icons.cloud),
title: new Text('weather'),
),
],
onTap: (int index) {
_history.add(index);
setState(() => _currentIndex = index);
Navigator.push(context, new BottomNavigationRoute()).then((x) {
_history.removeLast();
setState(() => _currentIndex = _history.last);
});
},
),
);
}
}
class BottomNavigationRoute extends LocalHistoryRoute<void> {}
Our app is built on top of Scaffold and to this point we have been able to accommodate most of our routing and navigation requirements using the provided calls within NavigatorState (pushNamed(), pushReplacementNamed(), etc.). What we don't want though, is to have any kind of 'push' animation when a user selects an item from our drawer (nav) menu. We want the destination screen from a nav menu click to effectively become the new initial route of the stack. For the moment we are using pushReplacementNamed() for this to ensure no back arrow in the app bar. But, the slide-in-from-the-right animation implies a stack is building.
What is our best option for changing that initial route without animation, and, can we do that while also concurrently animating the drawer closed? Or are we looking at a situation here where we need to move away from Navigator over to just using a single Scaffold and updating the 'body' directly when the user wants to change screens?
We note there is a replace() call on NavigatorState which we assume might be the right place to start looking, but it's unclear how to access our various routes originally set up in new MaterialApp(). Something like replaceNamed() might be in order ;-)
What you're doing sounds somewhat like a BottomNavigationBar, so you might want to consider one of those instead of a Drawer.
However, having a single Scaffold and updating the body when the user taps a drawer item is a totally reasonable approach. You might consider a FadeTransition to change from one body to another.
Or, if you like using Navigator but don't want the default slide animation, you can customize (or disable) the animation by extending MaterialPageRoute. Here's an example of that:
import 'package:flutter/material.dart';
void main() {
runApp(new MyApp());
}
class MyCustomRoute<T> extends MaterialPageRoute<T> {
MyCustomRoute({ WidgetBuilder builder, RouteSettings settings })
: super(builder: builder, settings: settings);
#override
Widget buildTransitions(BuildContext context,
Animation<double> animation,
Animation<double> secondaryAnimation,
Widget child) {
if (settings.isInitialRoute)
return child;
// Fades between routes. (If you don't want any animation,
// just return child.)
return new FadeTransition(opacity: animation, child: child);
}
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return new MaterialApp(
title: 'Navigation example',
onGenerateRoute: (RouteSettings settings) {
switch (settings.name) {
case '/': return new MyCustomRoute(
builder: (_) => new MyHomePage(),
settings: settings,
);
case '/somewhere': return new MyCustomRoute(
builder: (_) => new Somewhere(),
settings: settings,
);
}
assert(false);
}
);
}
}
class MyHomePage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return new Scaffold(
appBar: new AppBar(
title: new Text('Navigation example'),
),
drawer: new Drawer(
child: new ListView(
children: <Widget> [
new DrawerHeader(
child: new Container(
child: const Text('This is a header'),
),
),
new ListTile(
leading: const Icon(Icons.navigate_next),
title: const Text('Navigate somewhere'),
onTap: () {
Navigator.pushNamed(context, '/somewhere');
},
),
],
),
),
body: new Center(
child: new Text(
'This is a home page.',
),
),
);
}
}
class Somewhere extends StatelessWidget {
Widget build(BuildContext context) {
return new Scaffold(
body: new Center(
child: new Text(
'Congrats, you did it.',
),
),
appBar: new AppBar(
title: new Text('Somewhere'),
),
drawer: new Drawer(
child: new ListView(
children: <Widget>[
new DrawerHeader(
child: new Container(
child: const Text('This is a header'),
),
),
],
),
),
);
}
}
Use PageRouteBuilder like:
Navigator.push(
context,
PageRouteBuilder(
pageBuilder: (_, __, ___) => Screen2(),
transitionDuration: Duration.zero,
),
);
And if you want transition, simply add following property to above PageRouteBuilder, and change seconds to say 1.
transitionsBuilder: (_, a, __, c) => FadeTransition(opacity: a, child: c),