Most voted "dart" questions
Dart is a web-based language developed by Google. The goal of the Dart language is to replace Javascript as the main language of browsers. Programs in this language can be either run on a virtual machine or compiled for Javascript.
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answer45
viewsCircularcountdowntimer doesn’t change the time when I change the page
I’m new to flutter and I’m creating a fitness app for a school project. However, I have a problem with my Circularcountdowntimer, because when I press the button to change the exercise the time…
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answers32
viewsHow do I receive a variable or function within the Textformfield input without having to type and save to the list with Flutter?
I need to insert a text inside the input so there is no need for typing, it was a way to edit the data stored in Firebase, when I edit the data, goes to an editing screen with the data in each…
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answer21
viewsTabbarview inside a Slivertoboxadapter
I need to add a tabbarview inside the Slivertoboxadapter, but nothing I try works. I want to generate a chart for each tab, but I can’t even insert any message. Below is my code: class StatsScreen…
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answer116
viewserror: The argument type 'Jsobject' can’t be Assigned to the Parameter type 'Buildcontext'
I’m trying to navigate from the login screen to the homescreen, but when creating the void _onSuccess is returning the error: error: The argument type 'Jsobject' can’t be Assigned to the Parameter…
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answer62
viewsHow to remove Textfield edge?
I’m making an autocomplete, it works perfectly, but it adds this edge on the input, I already used border.None, enabledBorder: Inputborder.None, among other things and I’m not able to remove. If…
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answers45
viewssetState on Flutter works only the first time
I’m studying Flutter and decided to make a cart, I have the product widget and widget to list products. The problem is that when I first click on add it adds in the cart and updates the amount in…
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answer31
viewsProblem displaying a captured json from an API in my column widget - Flutter
I have a problem I couldn’t solve, so I’m coming to you to give me a hand. I’m searching for a json from an API, the data search process goes well (I use a print() that shows me that if I got the…
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answers39
viewsError after updating package name (app does not run)
I rename my package and after my application does not run anymore. I’ve updated the name on all the files that are required (Androidmanifest in debug, main and profile and Kotlin) but it doesn’t run…
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answer32
viewsErrortext conditional does not work
I’m trying to use a validation on Textfield, I tried it as Textformfield too, but without success! I would like that when typing or pressing the Confirm button, the error message appears or not in…
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answers30
viewsHow to keep login active Flutter Firebase
Good afternoon, I’m having a hard time keeping my login active in my app, either by email or by google account. I tried the Sharedpreferences method but I was not very successful. This is the login…
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answers37
viewsHow to use the same Stream on different pages in Dart?
Hello! I am creating an application using Clean Architecture as a base. In the context of my problem, I have a Tabbarview that has 4 indexs. In the numbers 0 and 3, there is a component that will be…
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answer30
viewsDisplay Future variable on an Elevatedbutton
I am making the call in my database of the boarding number, I need to put this number inside a button, but my variable "boarding" appears as undefined inside the Elevatedbutton import…
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answer28
viewsHow to validate if the value of one form is equal to the value of the other in the Textformfield attribute'Validator()
Hello! I have a _textFieldValue() component, so you don’t have to replay the same code more than once. Component _textFieldValue() Widget _textFieldValue(String title, TextEditingController…
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answers16
views(GETX) Class 'String' has no instance getter 'Description'." Tried Calling: Description
I’m trying to do 2 Dropdownbutton, the first that when selecting the UF the second list of its cities however I’m not getting at all, I’m making the request and adding the cities of this request in…
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answer34
viewsSearchdelegate do not return to page in release mode
I have this code on Searchdelegate class CustomSearchDelegate extends SearchDelegate<String> { @override List<Widget> buildActions(BuildContext context) { return [ IconButton( icon:…
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answer32
viewsFunction to create buttons according to the database
I have in my database several information and that for each information there should be a button that directs the user to the screen where a guide will be displayed according to the chosen option.…
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answers36
viewstype 'Future<Dynamic>' is not a subtype of type 'Set<Marker>'
Basically this code searches for the delivery locations already inserted in the databank and adds a marker on the map for them, in addition to showing the real-time position of the user. The error…
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answers14
viewsCreation of Resources in Woocommerce
Good afternoon, I’m creating a flutter/Dart app and I’m not getting permission to create a new client. I’ve already modified . htaccess and everything. In my cPanel I have 5 domains and as I am…
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answers58
viewsPassword visibility icon appearing when it should not be displayed
I am making a login screen and in it I will leave the option to make visible or not the password. I already have everything set up, but for some reason a second button appears that I did not create.…
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answers33
viewsHow to get the return of a javascript variable with Flutter Web
Colleagues, please, I need to receive the return variable from this encryption library below. My application is in Flutter Web, and I don’t know how to include Javascript in Flutter Web. I’ve done a…
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answer31
viewsHow to read multiple values in a single line on Dart?
How do I read more than one value in a single line? For the exercise I’m doing says the following: the input file contains two rows of data. In each row there will be 3 values, respectively two…
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answers22
viewsTextfield componentization with color changes
After componentization of a Textfield from the login page, the color changes (fillColor and labelStyle) do not work properly. The main class login_view calls the Component (Textfieldcomponent). //…
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answers22
viewsProblem "Instance Member can’t be accessed using Static access." in a simple registration system
I’m trying to create a registration system and for some reason I can’t access the "put" (add) method, located in the "users.Dart", on the screen where the entries are shown, the "cadastros.Dart".…
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answer353
viewsConvert Brazilian to American date to parse for a Date object
I’m making an application that reads an html page and gets some information, among them a date. This date is in Portuguese, in the following format: "23 March 2019". I wonder if you have any way to…
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answer418
viewsHow to reverse the order of a String in Dart?
I know that in other languages have methods to get the inverse of a String and I’ve searched Dart, but I’m not finding anything. I’m doing like this: String inverter(String v) { String inverso ='';…
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answer121
viewsError to return Dart/flutter value
Good evening, you guys. I am trying to learn how to use Bloc with rxdart. I am having difficulty recovering the value of the API When debugging does not know if an Exception appears it follows…
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answer601
viewsFlutter: Error when adding more than 3 items to a Listview
Hello, all the Listview of my application in Flutter if add more than 3 items occurs to Exception below: I/flutter (13259): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY…
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answer733
viewsError to recover a Future List<Class> Dart
People are having trouble recovering data from a future function when arriving in snapshot... presents this error: AsyncSnapshot<List<Episodio>>(ConnectionState.done, null, Exception:…
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answer518
viewsDay Scrolling for Month Scrolling
Good night! I have this example of day scrolling that makes the user scroll through the dates of the month with each click both forward and backward. However, I would like that, instead of every…
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answers524
viewsWhy this mistake in decorating my container on the flutter?
Cannot provide Both a color and a Decoration The color argument is just a shorthand for "Decoration: new Boxdecoration(color: color)". 'package:flutter/src/widgets/container.Dart': Failed assertion:…
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answer308
viewsFlutter cannot find pubspec.yaml when running run run
I did the installation of Dart + flutter for the first time today, I did the Getting Start oriented configuration of the official website itself, but when giving RUN in the project, this error…
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answer982
viewsNosuchmethoderror: The Setter 'gasoline=' was called on null
Good morning, I have an error that I cannot solve in my application, I need to make a calculation with the values received in certain attributes, but the attribute does not receive the values, I get…
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answers371
viewsPlacing Dynamic Width in a Container
Hello! I’m wanting to use this control to replace the Dropdown, but I realized that its width command 'does not work', maybe by the context external to it, I didn’t get it right. Because I want to…
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answer54
viewsAs I inform a condition for when the screen is changed the timer.Eriodic cancel
Today I use so with the code below, but it doesn’t work very well, because when changing screen the query continues to be executed in background. Future _refresh() async { if (_statusLote !=…
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answers352
viewsWhat mistake is this and what can I do to fix it?
Error: ADB exited with Exit code 1 Performing Streamed Install adb: failed to install C: pedidos build app outputs apk app.apk: Failure [INSTALL_FAILED_UPDATE_INCOMPATIBLE: Package with.ample…
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answer1039
viewsasync x await x Future
What are Keywords for async and await in Flutter? Some doubts I have are: 1 - They belong to Flutter or Dart? 2 - Why put the async at the end of the following method? void _method(TodoItem item)…
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answer1687
viewsBottom Overflowed
import 'package:flutter/material.dart'; //import 'package:font_awesome_flutter/font_awesome_flutter.dart'; //import 'package:flutter/widgets.dart'; //import…
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answer1221
viewsError with Map<String, Dynamic> - Cannot recognize String as Dynamic
I have the following Flutter error: type '_InternalLinkedHashMap<String, dynamic>' is not a subtype of type 'String' This error is occurring when I have run the code seginte: List…
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answer479
viewsHow to limit a composite query in Firebase/flutter
I made a simple query this way and works correctly, it saves only once in the database, not repeating the same value. final QuerySnapshot result = await Future.value(Firestore.instance…
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answer384
viewsHow to access the changed value of a variable of another class?
I have two classes, my app’s home screen class (Homescreen) and my button class (Button). I have this function in my button class: bool variável = false; void alterarValor() { setState((){ variável…
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answer599
viewsFlutter calling a dialog inside an onTap()
I’m having a problem in a APP development on flutter, I’m trying to call a method inside an onTap(); however this presenting the following error: "The Return type 'void' isn’t a 'Widget', as defined…
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answer198
viewsError trying to change the configured Locale using a Dart library
I’m trying to set up a new one locale on another screen of the application, but it says that the object I try to access is null, but I did exactly as the example, I’m not finding the error.…
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answer345
viewsUpdate to Flutter/Dart database
I need to change only the comment field of a contact. But when I try to change this field accuses this error type 'int' is not a subtype of type 'Client'. I wonder why, since the update function…
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answer381
viewsPass Values through Stream / Bloc
I have a login_bloc.Dart file and within it I have the following situation. final usuario = BehaviorSubject<String>(); usuario.sink.add(user.email); and in the file home_screen.Dart, I have…
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answer95
viewsError in calculation - Flutter
I am cracking my head in a problem that is giving in my debug in an application of mine which is as follows: "The method '>' was called on null. Receiver: null Tried Calling: >(0)" Follow the…
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answer3464
views(Solved) ERROR: Flutter Unhandled Exception: type 'Future<Dynamic>' is not a subtype of type 'List<Oficioenviado>
I’m trying to make an Infinit scroll, I have a consumption of an api where I take the data and convert with my model to json, I want to insert this data in variable, where when arriving at the end…
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answer906
viewsUpdate a Listview in a Statefulwidget Son Flutter
my main layout features an aapBar, body and bottomNavigationBar through the bottomNavigationBar I update the body with other screens, which show a listview, in the appBar from the main screen I have…
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answer197
viewsHow to save value correctly in Sharedpreferences? - Flutter
Hello, everybody! Where am I going wrong? I have login with google to pick up the token and send to graphgl. This token is saved - at least that’s what it should be - in sharedpreferences, but it’s…
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answer854
viewsNavigation between flutter screens
I have the following code, which is called in main.Dart to display, and I would like to navigate to another screen(class), but when I use routes, when I call the element navigator, he of the error…
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answer567
viewsOld projects with error after Flutter update
A Flutter update was made using the command: git clone -b stable https://github.com/flutter/flutter.git After this update, some old projects have several bugs (here are some of them): List _toDoList…