I tried to use $url inside lodfromurl() function but I cant defined $url inside lodfromurl() ! can you help me please ?
Package Used flutter_plugin_pdf_viewer
The full code is :
import 'package:example/Home/booklist.dart';
import 'package:flutter/material.dart';
import 'package:flutter_plugin_pdf_viewer/flutter_plugin_pdf_viewer.dart';
class PDFViwer extends StatefulWidget {
final String url;
PDFViwer({Key key, #required this.url}) : super(key: key);
#override
_PDFViwerState createState() => _PDFViwerState();
}
class _PDFViwerState extends State<PDFViwer> {
#override
void initState() {
// TODO: implement initState
super.initState();
lodfromurl();
}
PDFDocument document;
bool _isLoading = true;
lodfromurl()async{
document = await PDFDocument.fromURL($url);
setState(() {
_isLoading = false;
});
}
}
Url isn't defined in your state class so you have to use widget. to access variable.
import 'package:example/Home/booklist.dart';
import 'package:flutter/material.dart';
import 'package:flutter_plugin_pdf_viewer/flutter_plugin_pdf_viewer.dart';
class PDFViwer extends StatefulWidget {
final String url;
PDFViwer({Key key, #required this.url}) : super(key: key);
#override
_PDFViwerState createState() => _PDFViwerState();
}
class _PDFViwerState extends State<PDFViwer> {
#override
void initState() {
// TODO: implement initState
super.initState();
lodfromurl();
}
PDFDocument document;
bool _isLoading = true;
lodfromurl()async{
document = await PDFDocument.fromURL(widget.url);
setState(() {
_isLoading = false;
});
}
}
Related
How to solve this error?
The named parameter 'key' is required, but there's no corresponding argument. (Documentation) Try adding the required argument.
error
Future<void> onJoin() async {
// update input validation
setState(() {
_channelController.text.isEmpty
? _validateError = true
: _validateError = false;
});
if (_channelController.text.isNotEmpty) {
await _handleCameraAndMic(Permission.camera);
await _handleCameraAndMic(Permission.microphone);
await Navigator.push(
context,
MaterialPageRoute(
builder: (context) => VideoCall(
channelName: _channelController.text,
role: _role,
),
),
);
}
}
class VideoCall
class VideoCall extends StatefulWidget {
final String channelName;
final ClientRole role;
const VideoCall({Key key, required this.channelName, required this.role})
: super(key: key);
#override
_VideoCallState createState() => _VideoCallState();
}
class _VideoCallState extends State<VideoCall> {
final _users = <int>[];
final _infoStrings = <String>[];
bool muted = false;
late RtcEngine _engine;
#override
void dispose() {
// clear users
_users.clear();
// destroy sdk
_engine.leaveChannel();
_engine.destroy();
super.dispose();
}
#override
void initState() {
super.initState();
// initialize agora sdk
initialize();
}
this is the videoCall class in there no any error shows.
when add "key" show this
When remove required property from key in video call class
show this error
In VideoCall class, key property set as a required, change it to optional:
class VideoCall extends StatefulWidget {
final String? channelName;
final ClientRole? role;
const VideoCall({Key? key, this.channelName, this.role})
: super(key: key);
#override
_VideoCallState createState() => _VideoCallState();
}
Why does not generic Future<T> assign work? i Get this error: A value of type 'Future<T>?' can't be assigned to a variable of type 'Future<T>?'.
typedef SimpleFutureFunction<T> = Widget Function(void Function(Future<T>? newFuture) onFuture);
class SimpleFuture<T> extends StatefulWidget {
const SimpleFuture({Key? key, required this.simple, this.future}) : super(key: key);
final SimpleFutureFunction simple;
final Future<T>? future;
#override
State<SimpleFuture> createState() => _SimpleFutureState();
}
class _SimpleFutureState<T> extends State<SimpleFuture<T>> {
Future<T>? _future;
#override
void initState() {
super.initState();
_future = widget.future;
}
#override
Widget build(BuildContext context) {
return widget.simple.call(<T>(Future<T>? newFuture) {
setState(() {
_future = newFuture;
});
});
}
}
All of the sudden I am getting the error DataStore plugin has not been added to Amplify, recoverySuggestion: Add DataStore plugin to Amplify and call configure before calling DataStore related APIs to rule out any of the work I was doing on that page I tried it on a fresh page with the same result.
I already did execute amplify codegen models, amplify pull and amplify env pull. Also tried to do a flutter clean but I don't see any change at all. I'm really puzzled and can't seem to figure out the issue.
One thing I did notice while debugging was that the initState of the screen seems to be executed earlier as the configureAmplify callback.
I will show the relevant parts of the code (sorry for the long code in advance).
Pubspec.yaml
dependencies:
...
amplify_flutter: ^0.2.10
amplify_datastore: ^0.2.10
amplify_api: ^0.2.10
amplify_auth_cognito: ^0.2.10
amplify_storage_s3: ^0.2.10
main.dart
import 'package:flutter/material.dart';
import 'package:my_package/screens/main/teams_screen.dart';
import 'package:my_package/services/amplify_services.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatefulWidget {
const MyApp({Key? key}) : super(key: key);
#override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
#override
void initState() {
super.initState();
AmplifyService.configureAmplify();
}
#override
Widget build(BuildContext context) {
...
}
}
services/amplify_services.dart
import 'package:flutter/foundation.dart';
import 'package:amplify_flutter/amplify.dart';
import 'package:amplify_datastore/amplify_datastore.dart';
import 'package:amplify_api/amplify_api.dart';
import 'package:amplify_auth_cognito/amplify_auth_cognito.dart';
import 'package:amplify_storage_s3/amplify_storage_s3.dart';
import 'package:my_package/models/ModelProvider.dart';
import 'package:my_package/amplifyconfiguration.dart';
class AmplifyService {
static configureAmplify() async {
AmplifyAPI apiPlugin = AmplifyAPI();
AmplifyAuthCognito authPlugin = AmplifyAuthCognito();
AmplifyStorageS3 amplifyStorageS3 = AmplifyStorageS3();
AmplifyDataStore dataStorePlugin = AmplifyDataStore(
modelProvider: ModelProvider.instance,
);
await Amplify.addPlugins([
dataStorePlugin,
authPlugin,
amplifyStorageS3,
apiPlugin,
]);
try {
await Amplify.configure(amplifyconfig);
} on AmplifyAlreadyConfiguredException {
if (kDebugMode) {
print(
"Amplify was already configured. Looks like app restarted on android.");
}
}
}
}
Lastly the very basic page with not even an output (screens/teams_screen.dart)
import 'dart:async';
import 'package:amplify_datastore/amplify_datastore.dart';
import 'package:amplify_flutter/amplify.dart';
import 'package:flutter/material.dart';
import 'package:my_package/models/Team.dart';
class TeamsScreen extends StatefulWidget {
const TeamsScreen({Key? key}) : super(key: key);
#override
_TeamsScreenState createState() => _TeamsScreenState();
}
class _TeamsScreenState extends State<TeamsScreen> {
late StreamSubscription<QuerySnapshot<Team>> _teamsSubscription;
bool _isLoading = true;
List<Team> teams = [];
#override
void initState() {
super.initState();
_initializeApp();
}
#override
void dispose() {
_teamsSubscription.cancel();
super.dispose();
}
Future<void> _initializeApp() async {
_teamsSubscription = Amplify.DataStore.observeQuery(Team.classType)
.listen((QuerySnapshot<Team> snapshot) {
setState(() {
if (_isLoading) _isLoading = false;
teams = snapshot.items;
});
});
}
#override
Widget build(BuildContext context) {
return Container();
}
}
New day, fresh mind. The issue turned out to be quite simple, I didn't set an _isLoading state to indicate weter or not the configureAmplify callback was completed and let the app just continue loading all the other screens triggering the error. So after setting the state and only adding the rest of the app after the state was changed it worked without any problem.
To fix it I did the following:
import 'package:flutter/material.dart';
import 'package:my_package/screens/main/teams_screen.dart';
import 'package:my_package/services/amplify_services.dart';
void main() {
runApp(const MyApp());
}
class MyApp extends StatefulWidget {
const MyApp({Key? key}) : super(key: key);
#override
_MyAppState createState() => _MyAppState();
}
class _MyAppState extends State<MyApp> {
#override
void initState() {
super.initState();
_initializeApp();
}
Future<void> _initializeApp() async {
await AmplifyService.configureAmplify(); // note the await!
setState(() {
_isLoading = false; // important to set the state!
});
}
#override
Widget build(BuildContext context) {
return MaterialApp(
home: _isLoading
? Center(child: CircularProgressIndicator())
: const MainScreen(), // _isLoading is very important here.
);
}
}
I wanted to implements a simple tutorial of how parsing an Rss Feed with Flutter, here is my code:
import 'package:flutter/material.dart';
import 'package:webfeed/webfeed.dart';
import 'package:http/http.dart' as http;
import 'package:url_launcher/url_launcher.dart';
import 'package:cached_network_image/cached_network_image.dart';
class RSSParser extends StatefulWidget {
#override
_RSSParserState createState() => _RSSParserState();
}
class _RSSParserState extends State<RSSParser> {
final String url = "https://www.90min.com/posts.rss";
RssFeed _feed;
String _title;
static const String loadingFeedMsg = 'Loading Feed...';
static const String feedLoadErrorMsg = 'Error Loading Feed.';
static const String feedOpenErrorMsg = 'Error Opening Feed.';
Future<RssFeed> loadFeed() async{
try{
final client = http.Client();
final response = await client.get(url);
return RssFeed.parse(response.body);
}
catch(e){
}
return null;
}
updateTitle(title){
setState(() {
_title = title;
});
}
#override
void initState() {
// TODO: implement initState
super.initState();
updateTitle(widget.title);
}
updateFeed(feed){
setState(() {
_feed = feed;
});
}
#override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text(_title),
),
);
}
}
The problem is that i got a compilation error in that instruction
updateTitle(widget.title);
with the following error message:
The getter 'title' isn't defined for the type 'RSSParser'
In the tutorial, it works fine!!
Do you have an idea how to solve this?
Thank you
You haven't declared title for you RSS widget. It should look something like ths:
class RSSParser extends StatefulWidget {
final String title;
const RSSParser({required this.title});
This should solve your error.
This is not working because there is not title in RSS class.
I think you are not clear with use of widget.something. It means that in the class which extends StatefulWidget there is a something parameter which i need to get in stateObject.
See the code to understand.
class YellowBird extends StatefulWidget {
const YellowBird({ Key? key }) : super(key: key);
String someData = 'SomeData'; // Some data
#override
_YellowBirdState createState() => _YellowBirdState();
}
//This is the state object
class _YellowBirdState extends State<YellowBird> {
// Now that if you need some data from the above class. You use use this widget.someData to get it here
String getHere = widget.someData ;
#override
Widget build(BuildContext context) {
return Container(color: const Color(0xFFFFE306));
}
}
I have I loading indicator dialog in my main app component. I like to call showLoadingDlg from a sub component. I tried _AppLayoutPageState state = _AppLayoutPageState .of(context); but I'm able to import _AppLayoutPageState in my sub component.
class AppLayoutPage extends StatefulWidget {
AppLayoutPage({Key key, this.title}) : super(key: key);
final String title;
#override
_AppLayoutPageState createState() => _AppLayoutPageState();
}
class _AppLayoutPageState extends State<AppLayoutPage> {
bool _loading = false;
showLoadingDlg() {
setState(() {
_loading = true;
});
}
hideLoadingDlg() {
setState(() {
_loading = false;
});
}
...
I would advise you to use the bloc pattern and share a stream between your components, You can listen for the stream in your root widget and then you can send some data through the stream from your child widget to show the dialog.