flutter

How to wait for forEach to complete with asynchronous callbacks?

Iterable.forEach, Map.forEach, and Stream.forEach are meant to execute some code on each element of a collection for side effects. They take callbacks that have a void return type. Consequently, those .forEach methods cannot use any values returned by the callbacks, including returned Futures. If you supply a function that returns a Future, that Future will … Read more

No data from sever API’s is not showing on Listview using flutter

Try To below Code Your problem has been solved: Create API Call Function : Future<List<dynamic>> getJobsData() async { String url=”https://hospitality92.com/api/jobsbycategory/All”; var response = await http.get(Uri.parse(url), headers: { ‘Content-Type’: ‘application/json’, ‘Accept’: ‘application/json’, }); return json.decode(response.body)[‘jobs’]; } Write/Create your Widget : Center( child: FutureBuilder<List<dynamic>>( future: getJobsData(), builder: (context, snapshot) { if (snapshot.hasData) { return Padding( padding: const … Read more

How to display response from the server in Flutter app screen?

You should try below code: Your API Call Function Future<Album> fetchPost() async { String url=”https://jsonplaceholder.typicode.com/albums/1″; var response = await http.get(Uri.parse(url), headers: { ‘Content-Type’: ‘application/json’, ‘Accept’: ‘application/json’, }); if (response.statusCode == 200) { // If the call to the server was successful, parse the JSON return Album.fromJson(json .decode(response.body)); } else { // If that call was … Read more

“The operator can’t be unconditionally invoked because the receiver can be null” error after migrating to Dart null-safety

Dart engineer Erik Ernst says on GitHub: Type promotion is only applicable to local variables. … Promotion of an instance variable is not sound, because it could be overridden by a getter that runs a computation and returns a different object each time it is invoked. Cf. dart-lang/language#1188 for discussions about a mechanism which is … Read more

What is the difference between functions and classes to create reusable widgets?

Edit: The Flutter team has now taken an official stance on the matter and stated that classes are preferable. See https://www.youtube.com/watch?v=IOyq-eTRhvo TL;DR: Prefer using classes over functions to make reusable widget-tree. EDIT: To make up for some misunderstanding: This is not about functions causing problems, but classes solving some. Flutter wouldn’t have StatelessWidget if a … Read more

How to deal with unwanted widget build?

The build method is designed in such a way that it should be pure/without side effects. This is because many external factors can trigger a new widget build, such as: Route pop/push Screen resize, usually due to keyboard appearance or orientation change The parent widget recreated its child An InheritedWidget the widget depends on (Class.of(context) … Read more