I'm trying to build a WebApp in Flutter, and need to have a navigation bar on every page. I am using a MaterialApp with defined named routes. I tried adding my navigation bar as part of the body of a Scaffold element within the MaterialApp, though it seemed to replace the named route widges. Here is my code:
import 'package:client/components/Shared/NavigationBar.dart';
import 'package:client/views/CreateWedding.dart';
import 'package:client/views/Home.dart';
import 'package:flutter/material.dart';
void main() {
runApp(Admin());
}
class Admin extends StatelessWidget {
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
// home: Scaffold(
// body: Container(
// child: NavigationBar(),
// ),
// ),
initialRoute: Home.route,
routes: <String, WidgetBuilder>{
Home.route: (context) => Home(),
CreateWedding.route: (context) => CreateWedding()
},
);
}
}
Related
Here is the example given in the Flutter document of flutter_polyline_point
import 'package:flutter/material.dart';
import 'package:google_maps_flutter/google_maps_flutter.dart';
import 'package:flutter_polyline_points/flutter_polyline_points.dart';
import 'Constants.dart';
void main() => runApp(MyApp());
class MyApp extends StatelessWidget {
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Polyline example',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.orange,
),
home: MapScreen(),
);
}
}
class MapScreen extends StatefulWidget {
#override
_MapScreenState createState() => _MapScreenState();
}
class _MapScreenState extends State<MapScreen> {
GoogleMapController mapController;
double _originLatitude = 6.5212402, _originLongitude = 3.3679965;
double _destLatitude = 6.849660, _destLongitude = 3.648190;
Map<MarkerId, Marker> markers = {};
Map<PolylineId, Polyline> polylines = {};
List<LatLng> polylineCoordinates = [];
PolylinePoints polylinePoints = PolylinePoints();
String googleAPiKey = Constants.MAP_API_KEY;
#override
void initState() {
super.initState();
/// origin marker
_addMarker(LatLng(_originLatitude, _originLongitude), "origin",
BitmapDescriptor.defaultMarker);
/// destination marker
_addMarker(LatLng(_destLatitude, _destLongitude), "destination",
BitmapDescriptor.defaultMarkerWithHue(90));
_getPolyline();
}
#override
Widget build(BuildContext context) {
return SafeArea(
child: Scaffold(
body: GoogleMap(
initialCameraPosition: CameraPosition(
target: LatLng(_originLatitude, _originLongitude), zoom: 15),
myLocationEnabled: true,
tiltGesturesEnabled: true,
compassEnabled: true,
scrollGesturesEnabled: true,
zoomGesturesEnabled: true,
onMapCreated: _onMapCreated,
markers: Set<Marker>.of(markers.values),
polylines: Set<Polyline>.of(polylines.values),
)),
);
}
void _onMapCreated(GoogleMapController controller) async {
mapController = controller;
}
_addMarker(LatLng position, String id, BitmapDescriptor descriptor) {
MarkerId markerId = MarkerId(id);
Marker marker =
Marker(markerId: markerId, icon: descriptor, position: position);
markers[markerId] = marker;
}
_addPolyLine() {
PolylineId id = PolylineId("poly");
Polyline polyline = Polyline(
polylineId: id, color: Colors.red, points: polylineCoordinates);
polylines[id] = polyline;
setState(() {});
}
_getPolyline() async {
PolylineResult result = await polylinePoints.getRouteBetweenCoordinates(
Constants.API_KEY,
PointLatLng(_originLatitude, _originLongitude),
PointLatLng(_destLatitude, _destLongitude),
travelMode: TravelMode.driving,
wayPoints: [PolylineWayPoint(location: "Sabo, Yaba Lagos Nigeria")]
);
if (result.points.isNotEmpty) {
result.points.forEach((PointLatLng point) {
polylineCoordinates.add(LatLng(point.latitude, point.longitude));
});
}
_addPolyLine();
}
}
What is the difference between API_KEY and MAP_API_KEY? I am getting error there while trying to execute the example.
My requirement is to get the polyline points between two places in google map.
Kindly suggest me some examples to get the polyline drawn; if you have. I am getting problem in drawing the routes. Tried many examples but not getting it.
To use google maps, you need to get an API key from the following link:
https://developers.google.com/maps/documentation/javascript/get-api-key
This should be the MAP_API_KEY constant.
To use the direction api, you need to get an API key from the following link:
https://developers.google.com/maps/documentation/directions/get-api-key
This should be the API_KEY constant.
I am an absolute beginner to Flutter. I've been trying to follow various books, youtube videos, web guides, and in almost all of them fail when I'm following them at the very first hello world type Widget.
Here is an example of a bit of code given by a guide, which throws up a long error on a red screen on the virtual device, moaning about directionality:
import 'package:flutter/material.dart';
void main() => runApp(MaterialApp(
home: Text('Hello World'),
));
But if I change it like so, it works:
home: Text('Hello World', textDirection: TextDirection.ltr),
Firstly, do I need to set the textDirection for every text field, or can I set it globally? I'm surprised I have to set it at all - I would have thought left to right would have been the default if it wasn't specified.
Secondly, has flutter changed this recently? Every guide or tutorial or book I found was doesn't seem to have any textDirection set anywhere, has it changed or do I have an issue with my setup/config?
This is odd. You do not have to set textDirection usually. Infact, I never have. I believe your issue is just the missing Scaffold Widget.
Every Page should be contained in a Scaffold, it sets alot of standard values and is very important for many reasons.
return Scaffold(
body: Text("Hello World")
Here is a more complete. Standard starting point for a Flutter App.
main() calls runApp(MyApp)); which in turn sets MyHomePage() as it's starting point. In MyApp you can set some Appwide parameters, like Themes. Your actual UI and Code then goes into MyHomePage.
import 'package:flutter/material.dart';
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',
theme: ThemeData(
primarySwatch: Colors.blue,
),
home: MyHomePage(),
);
}
}
class MyHomePage extends StatefulWidget {
//This is your actual UI
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text("Tryout"),
),
body: Center(
),
);
}
}
Currently, I am working around routes and i wanted to set initialRoute in my app based on sharedPreferences value.
I am using Statedulwidget for my MaterialAppWidget and using setState() method once the data from sharedPrefs is fetched. But, every time i am getting the same screen.
class MyApp extends StatefulWidget {
#override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
int initScreen = 0;
initPrefs() async {
SharedPreferences prefs = await SharedPreferences.getInstance();
initScreen = prefs.getInt("initScreen");
print("initScreen ${initScreen}");
setState(() {});
}
#override
void initState() {
super.initState();
initPrefs();
}
#override
Widget build(BuildContext context) {
print("initScreen2 ${initScreen}");
return MaterialApp(
debugShowCheckedModeBanner: false,
title: 'Flutter Authentication',
theme: ThemeData(
primarySwatch: Colors.blue,
),
initialRoute: initScreen == 0 || initScreen == null
? MediatorPage.routeName
: PopUntilPage.routeName,
routes: {
CloudGroupCreate.routeName: (context) => CloudGroupCreate(),
CloudDashboard.routeName: (context) => CloudDashboard(),
PopUntilPage.routeName: (context) => PopUntilPage(),
ProviderWithFutureBuilderApp.routeName: (context) =>
ProviderWithFutureBuilderApp(),
MediatorPage.routeName: (context) => MediatorPage(),
},
);
}
}
I do not want to use direct widget using home property app. I just want to navigate through only and only using named routes.
Can anyone suggest how to do it properly ?
Thanks.
You need to init SharedPreferences in main() and use WidgetsFlutterBinding.ensureInitialized
You can copy paste run full code below
In demo , I set initScreen to 12
code snippet
int initScreen;
Future<void> main() async {
WidgetsFlutterBinding.ensureInitialized();
SharedPreferences prefs = await SharedPreferences.getInstance();
await prefs.setInt("initScreen",12);
initScreen = await prefs.getInt("initScreen");
print('initScreen ${initScreen}');
runApp(MyApp());
}
...
initialRoute: initScreen == 0 || initScreen == null
? "/"
: "first",
routes: {
'/': (context) => MyHomePage(title: "demo",),
"first": (context) => FirstPage(),
},
working demo
full code
import 'package:flutter/material.dart';
import 'package:shared_preferences/shared_preferences.dart';
//void main() => runApp(MyApp());
int initScreen;
Future<void> main() async {
WidgetsFlutterBinding.ensureInitialized();
SharedPreferences prefs = await SharedPreferences.getInstance();
await prefs.setInt("initScreen",12);
initScreen = await prefs.getInt("initScreen");
print('initScreen ${initScreen}');
runApp(MyApp());
}
class MyApp extends StatelessWidget {
// This widget is the root of your application.
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Flutter Demo',
theme: ThemeData(
// This is the theme of your application.
//
// Try running your application with "flutter run". You'll see the
// application has a blue toolbar. Then, without quitting the app, try
// changing the primarySwatch below to Colors.green and then invoke
// "hot reload" (press "r" in the console where you ran "flutter run",
// or simply save your changes to "hot reload" in a Flutter IDE).
// Notice that the counter didn't reset back to zero; the application
// is not restarted.
primarySwatch: Colors.blue,
),
initialRoute: initScreen == 0 || initScreen == null
? "/"
: "first",
routes: {
'/': (context) => MyHomePage(title: "demo",),
"first": (context) => FirstPage(),
},
//home: MyHomePage(title: 'Flutter Demo Home Page'),
);
}
}
class MyHomePage extends StatefulWidget {
MyHomePage({Key key, this.title}) : super(key: key);
// This widget is the home page of your application. It is stateful, meaning
// that it has a State object (defined below) that contains fields that affect
// how it looks.
// This class is the configuration for the state. It holds the values (in this
// case the title) provided by the parent (in this case the App widget) and
// used by the build method of the State. Fields in a Widget subclass are
// always marked "final".
final String title;
#override
_MyHomePageState createState() => _MyHomePageState();
}
class _MyHomePageState extends State<MyHomePage> {
int _counter = 0;
void _incrementCounter() {
setState(() {
// This call to setState tells the Flutter framework that something has
// changed in this State, which causes it to rerun the build method below
// so that the display can reflect the updated values. If we changed
// _counter without calling setState(), then the build method would not be
// called again, and so nothing would appear to happen.
_counter++;
});
}
#override
Widget build(BuildContext context) {
// This method is rerun every time setState is called, for instance as done
// by the _incrementCounter method above.
//
// The Flutter framework has been optimized to make rerunning build methods
// fast, so that you can just rebuild anything that needs updating rather
// than having to individually change instances of widgets.
return Scaffold(
appBar: AppBar(
// Here we take the value from the MyHomePage object that was created by
// the App.build method, and use it to set our appbar title.
title: Text(widget.title),
),
body: Center(
// Center is a layout widget. It takes a single child and positions it
// in the middle of the parent.
child: Column(
// Column is also a layout widget. It takes a list of children and
// arranges them vertically. By default, it sizes itself to fit its
// children horizontally, and tries to be as tall as its parent.
//
// Invoke "debug painting" (press "p" in the console, choose the
// "Toggle Debug Paint" action from the Flutter Inspector in Android
// Studio, or the "Toggle Debug Paint" command in Visual Studio Code)
// to see the wireframe for each widget.
//
// Column has various properties to control how it sizes itself and
// how it positions its children. Here we use mainAxisAlignment to
// center the children vertically; the main axis here is the vertical
// axis because Columns are vertical (the cross axis would be
// horizontal).
mainAxisAlignment: MainAxisAlignment.center,
children: <Widget>[
Text(
'You have pushed the button this many times:',
),
Text(
'$_counter',
style: Theme.of(context).textTheme.display1,
),
],
),
),
floatingActionButton: FloatingActionButton(
onPressed: _incrementCounter,
tooltip: 'Increment',
child: Icon(Icons.add),
), // This trailing comma makes auto-formatting nicer for build methods.
);
}
}
class FirstPage extends StatelessWidget {
#override
Widget build(BuildContext context) {
return Text("First");
}
}
A simple way to do this is to just use a flag when the load has completed, then, in build:
return _isLoadComplete? MaterialApp() : Container();
Another option, it seems like the MaterialApp is being cached, and initialRoute does not get run the 2nd time. Using a key seems to fix this:
return MaterialApp(
key: UniqueKey(),
//etc
I'd lean towards the first approach, as there's no point having MaterialApp try and show one view, will immediately replacing it with another.
I have added a webview plugin (official flutter plugin) for viewing webpages.
One of the webpage has a youtube video playing and when I press the home button and the app goes into background. But the problem is that the sound keeps on playing.
There are other sections in the application that contain some component playing sound or video.
So I want to know what can be done to pause the webview altogether once I move the app to background.
I am currently using this webview plugin: webview_flutter: ^0.3.9+1
There is no option in the plugin to pause the webview itself.
Got the same issue on Android side with webview_flutter: ^0.3.18+1.
I found a solution to pause the video by requesting audio focus again in the onPause callback of host Activity.
val audioManager = activity.getSystemService(Context.AUDIO_SERVICE) as AudioManager
if (audioManager.isMusicActive) {
if (Utils.hasOreoSDK26()) {
val audioAttributes = AudioAttributes.Builder()
.setUsage(AudioAttributes.USAGE_MEDIA)
.setContentType(AudioAttributes.CONTENT_TYPE_MUSIC)
.build()
val audioFocusRequest = AudioFocusRequest.Builder(AudioManager.AUDIOFOCUS_GAIN_TRANSIENT)
.setAudioAttributes(audioAttributes)
.setAcceptsDelayedFocusGain(true)
.setWillPauseWhenDucked(true)
.setOnAudioFocusChangeListener(
{ focusChange -> Timber.i(">>> Focus change to : %d", focusChange) },
Handler())
.build()
audioManager.requestAudioFocus(audioFocusRequest)
} else {
audioManager.requestAudioFocus({ }, AudioManager.STREAM_MUSIC,
AudioManager.AUDIOFOCUS_GAIN_TRANSIENT)
}
}
Also check this issue.
It's not possible from Dart using the webview_flutter plugin.
However, you can use my plugin flutter_inappwebview, which is a Flutter plugin that allows you to add inline WebViews or open an in-app browser window and has a lot of events, methods, and options to control WebViews.
It implements methods to pause/resume the WebView.
For Android, you can use InAppWebViewController.android.pause and InAppWebViewController.android.resume to pause and resume WebView.
You should implement WidgetsBindingObserver in your Widget and check AppLifecycleState state through didChangeAppLifecycleState() method.
If you need to pause/resume also JavaScript execution you can use InAppWebViewController.pauseTimers/InAppWebViewController.resumeTimers methods.
Here is an example with a YouTube URL:
import 'dart:async';
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:flutter_inappwebview/flutter_inappwebview.dart';
Future main() async {
WidgetsFlutterBinding.ensureInitialized();
runApp(MyApp());
}
class MyApp extends StatefulWidget {
#override
_MyAppState createState() => new _MyAppState();
}
class _MyAppState extends State<MyApp> with WidgetsBindingObserver {
InAppWebViewController webView;
#override
void initState() {
WidgetsBinding.instance.addObserver(this);
super.initState();
}
#override
void dispose() {
WidgetsBinding.instance.removeObserver(this);
super.dispose();
}
#override
void didChangeAppLifecycleState(AppLifecycleState state) {
print('state = $state');
if (webView != null) {
if (state == AppLifecycleState.paused) {
webView.pauseTimers();
if (Platform.isAndroid) {
webView.android.pause();
}
} else {
webView.resumeTimers();
if (Platform.isAndroid) {
webView.android.resume();
}
}
}
}
#override
Widget build(BuildContext context) {
return MaterialApp(
home: Scaffold(
appBar: AppBar(
title: const Text('InAppWebView Example'),
),
body: Container(
child: Column(children: <Widget>[
Expanded(
child: InAppWebView(
initialUrl: "https://www.youtube.com/watch?v=NfNdXgJZfFo",
initialHeaders: {},
initialOptions: InAppWebViewGroupOptions(
crossPlatform: InAppWebViewOptions(
debuggingEnabled: true,
),
),
onWebViewCreated: (InAppWebViewController controller) {
webView = controller;
},
onLoadStart: (InAppWebViewController controller, String url) {},
onLoadStop: (InAppWebViewController controller, String url) {},
))
])),
),
);
}
}
I have two dart pages. [1]: https://i.stack.imgur.com/D1xaf.png
In 2nd Page I have scrabbed text from a website and stored the value in a string called fetchedstring and it is printing the strings in console command line using the command print.
But I want this string to be showed in my main dart page.
How to do that?
//DART FILE 1 HAS THE FOLLOWING CODE
import 'package:flutter/material.dart';
import './function.dart';
void main() => runApp(new MyApp());
class MyApp extends StatelessWidget
{
#override
Widget build(BuildContext context)
{
return new MaterialApp(
home: new Scaffold(
appBar: new AppBar(),
body: new Center(
child: new String(fetchedtext),//Here I Want The Fetched Text
),
),
);
}
}
//DART PAGE 2 HAS THE FOLLOWING CODE
import 'package:http/http.dart' as http;
import 'package:html/parser.dart' as parser;
import 'package:html/dom.dart';
mainz() async
{
http.Response response = await http.get('https://www.google.com');
Document document = parser.parse(response.body);
document.getElementsByTagName('a').forEach((Element element)
{
final String fetchedText = element.text;
print(fetchedText);
}
);
}
//I WANT THAT String "fetchedtext" to be displayed in my Dart Page1.
If my understanding of what you are trying to do is correct, then you need to paste this at the very end of you function.dart file:
List get_elements() {
http.Response response = await http.get('https://www.google.com');
Document document = parser.parse(response.body);
document.getElementsByTagName('a').forEach((e) => print(e));
return document.getElementsByTagName('a');
}
Then modify one line in your main.dart:
child: get_elements().first;
Note that if you don't want to return the first found element, just remove first and use [] to chose what element you want to get, or if you want to get the whole list, just delete .first, but then you will get a String.
Use Futurebuilder class
import 'package:flutter/material.dart';
import 'dart:async';
void main() => runApp(new MyApp());
class MyApp extends StatelessWidget
{
#override
Widget build(BuildContext context)
{
var builder = FutureBuilder(
future: mainz(),
builder: (context, snapshot) {
if (snapshot.hasError) {
print(snapshot.error);
return new Text("${snapshot.error}");
}
return snapshot.hasData
? new Center(
child: Text(snapshot.data), //Here I Want The Fetched Text
)
: new CircularProgressIndicator();
},
);
return new MaterialApp(
home: new Scaffold(
appBar: new AppBar(
title: new Text("Title"),
),
body: builder,
)
);
}
}
Future<String> mainz() async
{
await new Future.delayed(new Duration(seconds: 3));
return 'Sample data';
}