Develop Reference

How to check for internet connection once for every screen in Flutter?

I want to check for internet connection at every screen on my app just like Telegram does and whenever user goes offline, show an Offline banner on the top of the screen.
I have tried using connectivity_plus and internet_connection_checker plugins to check for this but the problem is I have to subscribe to a stream for this and if the device goes offline once then there is no way to subscribe to it again without clicking a button.
getConnectivity() =>
subscription = Connectivity().onConnectivityChanged.listen(
(ConnectivityResult result) async {
isDeviceConnected = await InternetConnectionChecker().hasConnection;
if (!isDeviceConnected && isAlertSet == false) {
setState(() {
constants.offline = true;
print('Constants().offline ${constants.offline}');
isAlertSet = true;
});
}
print('off');
},
);
I'm using this code right now to check this issue but I don't want to replicate this code on each and every screen and even if I do replicate it then there will be a lot of subscriptions that I'll be subscribing to, which will mean that all the subscriptions will be disposed at the same time causing all sorts of issues.

If you have custom Scaffold, then you have to edit it. Otherwise, create a new one and change all Scaffolds to your custom one. This allows you to easily apply changes that should be on all pages.
Then, in the CustomScaffold create a Stack that contains page content and ValueListenableBuilder that listens to connection changes and if there is no internet displays error banner.
class CustomScaffold extends StatefulWidget {
const CustomScaffold({Key? key}) : super(key: key);
#override
State<CustomScaffold> createState() => _CustomScaffoldState();
}
class _CustomScaffoldState extends State<CustomScaffold> with WidgetsBindingObserver {
StreamSubscription? connectivitySubscription;
ValueNotifier<bool> isNetworkDisabled = ValueNotifier(false);
void _checkCurrentNetworkState() {
Connectivity().checkConnectivity().then((connectivityResult) {
isNetworkDisabled.value = connectivityResult == ConnectivityResult.none;
});
}
initStateFunc() {
_checkCurrentNetworkState();
connectivitySubscription = Connectivity().onConnectivityChanged.listen(
(ConnectivityResult result) {
isNetworkDisabled.value = result == ConnectivityResult.none;
},
);
}
#override
void initState() {
WidgetsBinding.instance.addObserver(this);
initStateFunc();
super.initState();
}
#override
void didChangeAppLifecycleState(AppLifecycleState state) {
super.didChangeAppLifecycleState(state);
if (state == AppLifecycleState.resumed) {
_checkCurrentNetworkState();
}
}
#override
void dispose() {
WidgetsBinding.instance.removeObserver(this);
connectivitySubscription?.cancel();
super.dispose();
}
#override
Widget build(BuildContext context) {
return Stack(
fit: StackFit.expand,
children: [
Scaffold(
...
),
ValueListenableBuilder(
valueListenable: isNetworkDisabled,
builder: (_, bool networkDisabled, __) =>
Visibility(
visible: networkDisabled,
child: YourErrorBanner(),
),
),
],
);
}
}

First I created an abstract class called BaseScreenWidget
used bloc state management to listen each time the internet connection changed then show toast or show upper banner with Blocbuilder
abstract class BaseScreenWidget extends StatelessWidget {
const BaseScreenWidget({Key? key}) : super(key: key);
#override
Widget build(BuildContext context) {
return Column(
children: [
baseBuild(context),
BlocConsumer<InternetConnectionBloc, InternetConnectionState>(
listener: (context, state) {
// if (!state.isConnected) {
// showToast("No Internet Connection");
// }
},
builder: (context, state) {
if (!state.isConnected) {
return const NoInternetWidget();
}
return const SizedBox.shrink();
},
),
],
);
}
Widget baseBuild(BuildContext context);
}
Made each screen only screen widgets contains Scaffold to extends BaseScreenWidget
class MainScreen extends BaseScreenWidget {
const MainScreen({super.key});
#override
Widget baseBuild(BuildContext context) {
return const Scaffold(
body: MainScreenBody(),
);
}
}
it's very helpful to wrap the Column with SafeArea in the build method in BaseScreen.

USE THIS SIMPLE TECHNIQUE only need this package: Internet Connection Checker. If you turn off your network it will tell you
connection_checker.dart
import 'dart:async';
import 'package:flutter/material.dart';
import 'package:internet_connection_checker/internet_connection_checker.dart';
final GlobalKey<NavigatorState> navigatorKey = GlobalKey<NavigatorState>();
class CheckMyConnection {
static bool isConnect = false;
static bool isInit = false;
static hasConnection(
{required void Function() hasConnection,
required void Function() noConnection}) async {
Timer.periodic(const Duration(seconds: 1), (_) async {
isConnect = await InternetConnectionChecker().hasConnection;
if (isInit == false && isConnect == true) {
isInit = true;
hasConnection.call();
} else if (isInit == true && isConnect == false) {
isInit = false;
noConnection.call();
}
});
}
}
base.dart
import 'package:flutter/material.dart';
import 'connection_checker.dart';
class Base extends StatefulWidget {
final String title;
const Base({Key? key, required this.title}) : super(key: key);
#override
State<Base> createState() => _BaseState();
}
class _BaseState extends State<Base> {
final snackBar1 = SnackBar(
content: const Text(
'Internet Connected',
style: TextStyle(color: Colors.white),
),
backgroundColor: Colors.green,
);
final snackBar2 = SnackBar(
content: const Text(
'No Internet Connection',
style: TextStyle(color: Colors.white),
),
backgroundColor: Colors.red,
);
#override
void initState() {
super.initState();
CheckMyConnection.hasConnection(hasConnection: () {
ScaffoldMessenger.of(navigatorKey.currentContext!)
.showSnackBar(snackBar1);
}, noConnection: () {
ScaffoldMessenger.of(navigatorKey.currentContext!)
.showSnackBar(snackBar2);
});
}
#override
Widget build(BuildContext context) {
return DefaultTabController(
length: 3,
child: Scaffold(
key: navigatorKey,
appBar: AppBar(
bottom: const TabBar(
tabs: [
Tab(icon: Icon(Icons.directions_car)),
Tab(icon: Icon(Icons.directions_transit)),
Tab(icon: Icon(Icons.directions_bike)),
],
),
title: const Text('Tabs Demo'),
),
body: const TabBarView(
children: [
Icon(Icons.directions_car),
Icon(Icons.directions_transit),
Icon(Icons.directions_bike),
],
),
),
);
}
}

I myself use connectivity_plus and I have never found the problem you mentioned (if the device goes offline once then there is no way to subscribe to it again without clicking a button), you can use my example.
If the user's internet is disconnected, a modal will appear. If the user is connected again, the modal will be deleted automatically.
Anyway, I put the option to check the internet again in the modal
class CheckConnectionStream extends GetxController {
bool isModalEnable = false;
final loadingCheckConnectivity = false.obs;
ConnectivityResult _connectionStatus = ConnectivityResult.none;
final Connectivity _connectivity = Connectivity();
late StreamSubscription<ConnectivityResult> _connectivitySubscription;
Future<void> initConnectivity() async {
late ConnectivityResult result;
try {
result = await _connectivity.checkConnectivity();
loadingCheckConnectivity.value = false;
} on PlatformException {
return;
}
return _updateConnectionStatus(result);
}
Future<void> _updateConnectionStatus(ConnectivityResult result) async {
_connectionStatus = result;
if (result == ConnectivityResult.none) {
if (isModalEnable != true) {
isModalEnable = true;
showDialogIfNotConnect();
}
} else {
if (isModalEnable) {
Get.back();
}
isModalEnable = false;
}
}
showDialogIfNotConnect() {
Get.defaultDialog(
barrierDismissible: false,
title: "check your network".tr,
onWillPop: () async {
return false;
},
middleText: "Your device is not currently connected to the Internet".tr,
titleStyle: TextStyle(
color: Get.isDarkMode ? Colors.white : Colors.black,
),
middleTextStyle: TextStyle(
color: Get.isDarkMode ? Colors.white : Colors.black,
),
radius: 30,
actions: [
Obx(() => loadingCheckConnectivity.value
? const CustomLoading(
height: 30.0,
radius: 30.0,
)
: ElevatedButton(
onPressed: () async {
loadingCheckConnectivity.value = true;
EasyDebounce.debounce(
'check connectivity',
const Duration(milliseconds: 1000), () async {
await initConnectivity();
});
},
child: Text(
'try again'.tr,
style: const TextStyle(color: Colors.white),
),
))
]);
}
#override
void onInit() {
super.onInit();
initConnectivity();
_connectivitySubscription =
_connectivity.onConnectivityChanged.listen(_updateConnectionStatus);
}
#override
void onClose() {
_connectivitySubscription.cancel();
super.onClose();
}
}

Flutter setState() not updating the view after Invoking Flutter Code From Native Side

I am trying to implement invoking Flutter Code From Native Side using method channel and working as expected. But having issue with rendering the view after trying to set the state. Can any one help to fix the issue?
Actually the SimSlotInfo is calling from the below widget,
List<Step> getSteps() {
return <Step>[
Step(
state: currentStep > 0 ? StepState.complete : StepState.indexed,
isActive: currentStep >= 0,
title: const Text("Send SMS"),
content: Column(
children: [
SimSlotInfo()
],
),
),
];
}
SimSlotInfo dart class
import 'dart:convert';
import 'package:flutter/material.dart';
import 'package:flutterdemo/model/device_slot.dart';
class SimSlotInfo extends StatefulWidget {
//callback function
final void Function(String) callBackFunction;
const SimSlotInfo(this.callBackFunction, {super.key});
//const SimSlotInfo({Key? key}) : super(key: key);
#override
State<SimSlotInfo> createState() => _SimSlotInfoState();
}
class _SimSlotInfoState extends State<SimSlotInfo> {
final platformMethodChannel = const MethodChannel('common_lib_plugin');
List<SimDetails> simDetailsObj = [];
//execute the below code while page loading
#override
void initState() {
super.initState();
platformMethodChannel.setMethodCallHandler(handleNativeMethodCall);
}
Future<void> handleNativeMethodCall(MethodCall call) async {
// do some processing
switch(call.method) {
case "deviceInfo":
var simData = call.arguments;
var arrayObjsText = '[{"slot":0,"simno":"89911017061","deviceid":"3518920","carrierName":"Vodafone"},{"slot":1,"simno":"89101706","deviceid":"3511643","carrierName":"JIO"}]';
List simObjsJson = jsonDecode(arrayObjsText) as List;
simDetailsObj = simObjsJson.map((tagJson) => SimDetails.fromJson(tagJson)).toList();
setState(() {
simDetailsObj = simDetailsObj;
});
}
}
#override
Widget build(BuildContext context) {
return Column(
children:
simDetailsObj.map((data) => RadioListTile(
dense: true,
contentPadding: EdgeInsets.zero,
title: Row(
mainAxisAlignment: MainAxisAlignment.spaceBetween,
children: [
Text(
"${data.carrierName}",
style: const TextStyle(color: Colors.black, fontSize: 18),
),
],
),
groupValue: _selectedSim,
value: data.simno,
onChanged: (val) {
},
)).toList()
);
}
}

First, you are trying to assign List to List so your code is getting brake there. to solve that loop the object with SimDetails object. and that will do the trick
ParentWidget
class _ParentWidgetState extends State<ParentWidget> {
#override
Widget build(BuildContext context) {
return ChildWidget( // <---- child widget
callSetState: (list) { // <--- callback Function
print(list);
setState(() {
// <---
});
},
);
}
}
In Child widget
class ChildWidget extends StatefulWidget {
const ChildWidget({Key? key, required this.callSetState}) : super(key: key);
final Function(List<SimDetails>) callSetState; // <-- declare callback function here
#override
State<ChildWidget> createState() => _ChildWidgetState();
}
and replace your setState with widget.callSetState
Future<void> handleNativeMethodCall(MethodCall methodCall) async {
switch (call.method) {
case 'deviceInfo':
var simData = call.arguments;
var arrayObjsText =
'[{"slot":0,"simno":"89911017061","deviceid":"3518920","carrierName":"Vodafone"},{"slot":1,"simno":"89101706","deviceid":"3511643","carrierName":"JIO"}]';
for (var data in jsonDecode(arrayObjsText)) {
simDetailsObj.add(
SimDetails(
slot: data['slot'],
simno: data['simno'],
deviceid: data['deviceid'],
carrierName: data['carrierName'],
),
);
}
/// setState(() {});
widget.callSetState(simDetailsObj);
break;
default:
}}

Json Empty after parse even though status 200

I am trying to parse a JSON after doing a HTTP GET request for my flutter app, however when it is parsed, the body shows as empty, this is the parsing code
urlHausParseBox() {
Future<_GoneSmishinState> fetchUrlResponse() async {
String url = myController.text;
final response = await http.post(
Uri.parse("https://urlhaus-api.abuse.ch/v1/url/"),
headers: <String, String>{
'Accept': 'application/json',
},
body: (<String, String>{
'url': url,
'query_status': query_status,
'url_status' : url_status,
//'status' : status,
//'urlStatus' : urlStatus,
}));
After this I have a check for the 200 status, and when recieved will return this to use after the fact, I printed the fields 'query_status' and 'url_status' but they came up empty so I printed what I was returning here
if (response.statusCode == 200) {
print (_GoneSmishinState.fromJson(jsonDecode(response.body)));
return _GoneSmishinState.fromJson(jsonDecode(response.body));
but all that is printed out is _GoneSmishinState#23f48(lifecycle state: created, no widget, not mounted)
which is not what is supposed to be returned by the HTTP GET request
The rest of my code is below
import 'dart:convert';
import 'package:validators/validators.dart';
import 'package:flutter/material.dart';
import 'package:sms/sms.dart';
import 'dart:io';
import 'dart:developer' as developer;
import 'package:http/http.dart' as http;
import 'package:flutter_local_notifications/flutter_local_notifications.dart';
String url = "https://urlhaus-api.abuse.ch/v1/urls/recent/"; //address for URL file
Future<void> main() async {
WidgetsFlutterBinding.ensureInitialized();
runApp(const MyApp());
}
class MyApp extends StatelessWidget {
const MyApp({Key? key}) : super(key:key);
#override
Widget build(BuildContext context) {
return const MaterialApp(
title: "Gone Smishin'",
home: GoneSmishin(),
);
}
}
class GoneSmishin extends StatefulWidget {
const GoneSmishin({Key? key}) : super(key: key);
State<GoneSmishin> createState() {
return _GoneSmishinState(url_status: '', query_status: '');
}
}
class _GoneSmishinState extends State<GoneSmishin> {
String message = "";
String word = "";
bool isOn = false;
final myController = TextEditingController();
#override
void dispose() {
myController.dispose();
super.dispose();
}
_GoneSmishinState({
required this.query_status,
required this.url_status,
});
final String query_status;
final String url_status;
factory _GoneSmishinState.fromJson(Map<String, dynamic> json) {
return _GoneSmishinState(
query_status: json["query_status"],
url_status: json["url_status"],
);
}
urlHausParseBox() {
Future<_GoneSmishinState> fetchUrlResponse() async {
String url = myController.text;
final response = await http.post(
Uri.parse("https://urlhaus-api.abuse.ch/v1/url/"),
headers: <String, String>{
'Accept': 'application/json',
},
body: (<String, String>{
'url': url,
'query_status': query_status,
'url_status' : url_status,
}));
if (response.statusCode == 200) {
print (_GoneSmishinState.fromJson(jsonDecode(response.body)));
return _GoneSmishinState.fromJson(jsonDecode(response.body));
} else {
throw Exception('Failed to load website');
}
}
fetchUrlResponse();
if (query_status == "ok" && url_status == "online") {
const Text ('Found in URLHause Database - Probably Smishing');
print("found");
} else if (query_status == "ok" && url_status == "offline") {
const Text ('Found in URLHaus, not online');
print("found offline");
} else {
const Text ('Found Nothing');
print("not found");
print (query_status);
print (url_status);
}
_pushInput() {
Navigator.of(context).push(
MaterialPageRoute<void>(
builder: (context) {
return Scaffold(
appBar: AppBar(
title: const Text ('Submit a Link')
),
body: (
Column(
mainAxisAlignment: MainAxisAlignment.center,
children: [
TextField (
controller: myController,
decoration: InputDecoration(
border: OutlineInputBorder(),
hintText: 'Enter your Link Text',
contentPadding: EdgeInsets.symmetric(
vertical: 40, horizontal: 20),
),
),
ElevatedButton(
onPressed: () {
urlHausParseBox();
},
child: const Text('Submit')
)
]
)
));
}
)
);
}
#override
var buttonText = 'OFF';
String textHolder = "App is Off";
changeTextON() {
setState(() {
textHolder = "App is ON";
});
isOn == true;
}
changeTextOFF() {
setState(() {
textHolder = "App is OFF";
});
isOn == false;
}
Widget build(BuildContext context) {
final ButtonStyle outlineButtonStyle = OutlinedButton.styleFrom(
primary: Colors.black87,
minimumSize: Size(200, 130),
padding: EdgeInsets.symmetric(horizontal: 200),
shape: const RoundedRectangleBorder(
borderRadius: BorderRadius.all(Radius.circular(300)),
),
).copyWith(
side: MaterialStateProperty.resolveWith<BorderSide>(
(Set<MaterialState> states) {
return BorderSide(
color: Theme.of(context).colorScheme.primary,
width: 1,
);
},
),
);
return Scaffold(
appBar: AppBar(
title: const Text("Gone Smishin'"),
actions: [
IconButton(
icon: const Icon(Icons.add_link),
onPressed: _pushInput,
tooltip: 'Submit a Link'
)
],
backgroundColor: Colors.red,
),
body: Column (
children: [
Container(
padding: EdgeInsets.fromLTRB(50, 50, 50, 50),
child: Text('$textHolder',
style: TextStyle(fontSize: 50)
),
),
Container(
//child: Text(result)
),
TextButton(
style: outlineButtonStyle,
onPressed: () {
changeTextON();
},
child: Text('ON')
),
TextButton(
style: outlineButtonStyle,
onPressed: () {
changeTextOFF();
},
child: Text("OFF"),
)
]
),
);
}
}

Change this:
_GoneSmishinState({
required this.query_status,
required this.url_status,
});
final String query_status;
final String url_status;
factory _GoneSmishinState.fromJson(Map<String, dynamic> json) {
return _GoneSmishinState(
query_status: json["query_status"],
url_status: json["url_status"],
);
}
to this:
_GoneSmishinState();
var queryStatus = '';
var urlStatus = '';
and this:
if (response.statusCode == 200) {
print (_GoneSmishinState.fromJson(jsonDecode(response.body)));
return _GoneSmishinState.fromJson(jsonDecode(response.body));
}
to:
if (response.statusCode == 200) {
setState(() {
final decoded = json.decode(response.body);
queryStatus = decoded['query_status'];
urlStatus = decoded['url_status'];
}
);
}
And, finally, patch up any unused/misnamed variables. As an aside, it's difficult to read functions declared inside other functions. Is fetchUrlResponse inside urlHausParseBox? Move it outside.

Agora in Flutter- navigating to the video chat screen more than one time keeps local video loading forever

I am using Agora for a one-to-one video chat purpose in Flutter.
User1 has an app to go online and user2 has another app to go online. After both of them go online, they can do video chat with one another. Both apps have almost similar codebase.
I have a screen or activity (say screen1) where an alert dialog is shown on tapping a button (say button1). On tapping the Continue button in the alert dialog, the dialog disappears and the user is taken to the screen (say screen2) where the video chat takes place. But after going to the video chat screen successfully, if the user taps on the back button on the mobile set then s/he is taken to screen1 and after tapping on button1, if the user taps on the Continue button in the popped up alert dialog, the user is again taken to screen2 but this time the local video (i.e. video of the user using the app) keeps loading for ever. Obviously I want the local video to load as it did for the first time.
I am gonna put my code here in such a way that you can easily run that.
Following code is for user1. For user2, no alert box is there in the app. Same code from user1 is used for user2 app, except the value of remoteUid is set to be 2 for user2 while this value is set to be 1 for user1. These are just two values identifying 2 users.
For user1:
main.dart:
import 'dart:async';
import 'dart:convert';
import 'package:flutter/material.dart';
import 'livesession1to1.dart';
void main() {
runApp(MessagingExampleApp());
}
class NavigationService {
static GlobalKey<NavigatorState> navigatorKey =
GlobalKey<NavigatorState>();
}
/// Entry point for the example application.
class MessagingExampleApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: 'Messaging Example App',
navigatorKey: NavigationService.navigatorKey, // set property
theme: ThemeData.dark(),
routes: {
'/': (context) => Application(),
'/liveSession1to1': (context) =>LiveSession1to1(),
},
);
}
}
int _messageCount = 0;
/// The API endpoint here accepts a raw FCM payload for demonstration purposes.
String constructFCMPayload(String? token, String server_key) {
_messageCount++;
return jsonEncode({
'token': token,
'to':token,
'data': {
'via': 'FlutterFire Cloud Messaging!!!',
'count': _messageCount.toString(),
},
'notification': {
'title': 'Hello FlutterFire!',
'body': 'This notification (#$_messageCount) was created via FCM! =============',
},
"delay_while_idle" : false,
"priority" : "high",
"content_available" : true
});
}
/// Renders the example application.
class Application extends StatefulWidget {
#override
State<StatefulWidget> createState() => _Application();
}
class _Application extends State<Application> {
String? _token;
#override
void initState() {
super.initState();
}
showAlertDialog() {
BuildContext context=NavigationService.navigatorKey.currentContext!;
// set up the buttons
Widget cancelButton = TextButton(
child: Text("Cancel"),
onPressed: () {},
);
Widget continueButton = TextButton(
child: Text("Continue"),
onPressed: () {
Navigator.of(context, rootNavigator: true).pop();
Navigator.of(context).pushNamed('/liveSession1to1');
},
);
Timer? timer = Timer(Duration(milliseconds: 5000), (){
Navigator.of(context, rootNavigator: true).pop();
});
showDialog(
context: context,
builder: (BuildContext builderContext) {
return AlertDialog(
backgroundColor: Colors.black26,
title: Text('One to one live session'),
content: SingleChildScrollView(
child: Text('Do you want to connect for a live session ?'),
),
actions: [
cancelButton,
continueButton,
],
);
}
).then((value){
// dispose the timer in case something else has triggered the dismiss.
timer?.cancel();
timer = null;
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('My App'),
),
floatingActionButton: Builder(
builder: (context) => FloatingActionButton(
onPressed: showAlertDialog,
backgroundColor: Colors.white,
child: const Icon(Icons.send),
),
),
body: SingleChildScrollView(
child: Text(
'Trigger Alert'
),
),
);
}
}
livesession1to1.dart:
import 'dart:async';
import 'package:agora_rtc_engine/rtc_engine.dart';
import 'package:agora_rtc_engine/rtc_local_view.dart' as RtcLocalView;
import 'package:agora_rtc_engine/rtc_remote_view.dart' as RtcRemoteView;
import 'package:flutter/material.dart';
import 'package:permission_handler/permission_handler.dart';
// const appId = "<-- Insert App Id -->";
// const token = "<-- Insert Token -->";
const appId = "......";// Put Agora App ID from Agora site here
const token = "....";// Put token ( temporary token avilable from Agora site)
void main() => runApp(MaterialApp(home: LiveSession1to1()));
class LiveSession1to1 extends StatefulWidget {
#override
_LiveSession1to1State createState() => _LiveSession1to1State();
}
class _LiveSession1to1State extends State<LiveSession1to1> {
int _remoteUid=1;
bool _localUserJoined = false;
late RtcEngine _engine;
#override
void initState() {
super.initState();
setState(() {});
initAgora();
}
Future<void> initAgora() async {
// retrieve permissions
await [Permission.microphone, Permission.camera].request();
// Create RTC client instance
RtcEngineContext context = RtcEngineContext(appId);
_engine = await RtcEngine.createWithContext(context);
await _engine.enableVideo();
_engine.setEventHandler(
RtcEngineEventHandler(
joinChannelSuccess: (String channel, int uid, int elapsed) {
print("local user $uid joined");
setState(() {
_localUserJoined = true;
});
},
userJoined: (int uid, int elapsed) {
print("remote user $uid joined");
setState(() {
_remoteUid = uid;
});
},
userOffline: (int uid, UserOfflineReason reason) {
print("remote user $uid left channel");
setState(() {
// _remoteUid = null;
_remoteUid = 0;
});
},
),
);
try {
await _engine.joinChannel(token, "InstaClass", null, 0);
} catch (e) {
print("error with agora = ");
print("$e");
print("error printeddddd");
}
}
// Create UI with local view and remote view
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Agora Video Call'),
),
body: Stack(
children: [
Center(
child: _remoteVideo(),
),
Align(
alignment: Alignment.topLeft,
child: Container(
width: 100,
height: 150,
child: Center(
child: _localUserJoined
? RtcLocalView.SurfaceView()
: CircularProgressIndicator(),
),
),
),
],
),
);
}
// Display remote user's video
Widget _remoteVideo() {
if (_remoteUid != 0) {
return RtcRemoteView.SurfaceView(
uid: _remoteUid,
channelId: "InstaClass",
);
}else {
print("'Please wait for remote user to join',");
return Text(
'Please wait for remote user to join',
textAlign: TextAlign.center,
);
}
}
}
For user2:
main.dart:
import 'dart:async';
import 'package:agora_rtc_engine/rtc_engine.dart';
import 'package:agora_rtc_engine/rtc_local_view.dart' as RtcLocalView;
import 'package:agora_rtc_engine/rtc_remote_view.dart' as RtcRemoteView;
import 'package:flutter/material.dart';
import 'package:permission_handler/permission_handler.dart';
const appId = "....."; // Same as user1 app
const token = "....."; // same as user1 app
void main() => runApp(MaterialApp(home: MyApp()));
class MyApp extends StatefulWidget {
#override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
// int? _remoteUid=1;
int _remoteUid=2;
bool _localUserJoined = false;
late RtcEngine _engine;
#override
void initState() {
super.initState();
initAgora();
}
Future<void> initAgora() async {
// retrieve permissions
await [Permission.microphone, Permission.camera].request();
//create the engine
_engine = await RtcEngine.create(appId);
await _engine.enableVideo();
_engine.setEventHandler(
RtcEngineEventHandler(
joinChannelSuccess: (String channel, int uid, int elapsed) {
print("local user $uid joined");
setState(() {
_localUserJoined = true;
});
},
userJoined: (int uid, int elapsed) {
print("remote user $uid joined");
setState(() {
_remoteUid = uid;
});
},
userOffline: (int uid, UserOfflineReason reason) {
print("remote user $uid left channel");
setState(() {
// _remoteUid = null;
_remoteUid = 0;
});
},
),
);
// await _engine.joinChannel(token, "test", null, 0);
await _engine.joinChannel(token, "InstaClass", null, 0);
}
// Create UI with local view and remote view
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Agora Video Call'),
),
body: Stack(
children: [
Center(
child: _remoteVideo(),
),
Align(
alignment: Alignment.topLeft,
child: Container(
width: 100,
height: 150,
child: Center(
child: _localUserJoined
? RtcLocalView.SurfaceView()
: CircularProgressIndicator(),
),
),
),
],
),
);
}
// Display remote user's video
Widget _remoteVideo() {
/*if (_remoteUid != null) {
return RtcRemoteView.SurfaceView(uid: _remoteUid!);
}*/
if (_remoteUid != 0) {
return RtcRemoteView.SurfaceView(
uid: _remoteUid,
channelId: "InstaClass",
);
}else {
return Text(
'Please wait for remote user to join',
textAlign: TextAlign.center,
);
}
}
}
In order to get the app ID and token, login to Agora site. After logging in, go to the 'Project Management' section to see the projects already created there. Under the Functions column, click on the key symbol and you will be taken to a page where you can generate a temporary token. On that page, give the channel name input the value 'InstaClass' as I have used this name in my code.
How to make the video chat work smoothly after the first time it works well ?

I think the problem is that when pressing back button you are just being taken to the previous screen and the call session is not being end. You can try by leaving the channel when pressing back button like :
_engine.leaveChannel();
End Call button sample
ElevatedButton(
onPressed: () {
_rtcEngine.leaveChannel();
Navigator.pop(context);
},
style: ButtonStyle(
shape: MaterialStateProperty.all(CircleBorder()),
backgroundColor: MaterialStateProperty.all(Colors.red),
padding: MaterialStateProperty.all(
EdgeInsets.fromLTRB(15, 15, 15, 12)),
),
child: Icon(
Icons.phone,
size: 30,
),
)
Back Button override using WillPopScope
return WillPopScope(
onWillPop: () async {
_rtcEngine.leaveChannel();
return true;
},
child: Scaffold(
body: Container(),
),
);

How to implement progress Indicator in web view for every page load flutter?

I am currently showing progress indicator before webview load using this code:
My Full main.dart code:
import 'dart:io';
import 'package:flutter/material.dart';
import 'package:webview_flutter/webview_flutter.dart';
//import 'package:mtcl/utils/AppColors.dart';
import 'package:custom_splash/custom_splash.dart';
import 'package:connectivity/connectivity.dart';
void main() {
//runApp(MyApp());
//var result = Connectivity().checkConnectivity();
WidgetsFlutterBinding.ensureInitialized();
runApp(MyApp());
// if (result == ConnectivityResult.none) {
// WidgetsFlutterBinding.ensureInitialized();
// runApp(MyApp());
// } else if (result == ConnectivityResult.mobile) {
// WidgetsFlutterBinding.ensureInitialized();
// runApp(MyApp());
// } else if (result == ConnectivityResult.wifi) {
// WidgetsFlutterBinding.ensureInitialized();
// runApp(MyApp());
// }
}
class MyApp extends StatelessWidget {
#override
Widget build(BuildContext context) {
return MaterialApp(
title: "MTCL Client",
debugShowCheckedModeBanner: false,
theme: ThemeData(
primarySwatch: Colors.red,
),
home: Scaffold(body: splash()));
}
}
class splash extends StatefulWidget {
#override
_splashState createState() => _splashState();
}
class _splashState extends State<splash> {
#override
Widget build(BuildContext context) {
return CustomSplash(
backGroundColor: Color(0xFFFF9800),
imagePath: "assets/images/logo.png",
home: WebViewClass(),
duration: 10,
animationEffect: "zoom-in",
);
}
}
class WebViewClass extends StatefulWidget {
WebViewState createState() => WebViewState();
}
class WebViewState extends State<WebViewClass> {
num position = 1;
final key = UniqueKey();
doneLoading(String A) {
setState(() {
position = 0;
});
}
startLoading(String A) {
setState(() {
position = 1;
});
}
//Check Internet Code Starts
//Check Internet Code Ended here
#override
Widget build(BuildContext context) {
return Scaffold(
//appBar: AppBar(title: Text('Show ProgressBar While Loading Webview')),
appBar: PreferredSize(
child: Container(),
preferredSize: Size.fromHeight(0.0),
),
body: IndexedStack(index: position, children: <Widget>[
WebView(
initialUrl: 'http://110.38.4.4/login/client',
javascriptMode: JavascriptMode.unrestricted,
key: key,
onPageFinished: doneLoading,
onPageStarted: startLoading,
),
Container(
color: Colors.white,
child: Center(
child: CircularProgressIndicator(
valueColor: new AlwaysStoppedAnimation<Color>(Colors.red),
)),
),
]));
}
}
Now what I need is to show the progress indicator instantly for every action like If the user clicks on login button after filling login credential, I want the progress indicator to be shown instantly after clicking the button while now the progress indicator is showing after a few moments of button click. How can I achieve such thing in flutter?

You can add your code that triggers the progress indicator inside navigationDelegate:
WebView(
initialUrl: 'https://flutter.dev',
navigationDelegate: (NavigationRequest request) {
print('Navigating to ${request.url}');
// Call any code here that you want
return NavigationDecision.navigate;
},
),

Based on navigationDelegate as suggested by Soares , this is my full working code
class _WikipediaExplorerState extends State<WikipediaExplorer> {
Completer<WebViewController> _controller = Completer<WebViewController>();
final Set<String> _favorites = Set<String>();
String title, url;
bool isLoading = true;
final _key = UniqueKey();
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: const Text('Facebook Test Webview'),
// This drop down menu demonstrates that Flutter widgets can be shown over the web view.
actions: <Widget>[
NavigationControls(_controller.future),
Menu(_controller.future, () => _favorites),
],
),
body: Builder(builder: (BuildContext context) {
return Stack(
children: <Widget>[
WebView(
initialUrl: 'https://www.facebook.com/',
javascriptMode: JavascriptMode.unrestricted,
onWebViewCreated: (WebViewController webViewController) {
_controller.complete(webViewController);
},
// TODO(iskakaushik): Remove this when collection literals makes it to stable.
// ignore: prefer_collection_literals
javascriptChannels: <JavascriptChannel>[
_toasterJavascriptChannel(context),
].toSet(),
navigationDelegate: (NavigationRequest request) {
if (request.url.startsWith('https://www.youtube.com/')) {
print('blocking navigation to $request}');
return NavigationDecision.prevent;
}
print('allowing navigation to $request');
setState(() {
isLoading = true;
});
return NavigationDecision.navigate;
},
onPageFinished: (String url) {
print('Page finished loading: $url');
setState(() {
isLoading = false;
});
},
),
isLoading
? Center(
child: CircularProgressIndicator(),
)
: Stack(),
],
);
}),
);
}
}
Every time a new link is clicked within the app, a circular progress dialog will be initiated