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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answer140
viewsError in Calculus
I have a problem with the conversion of String for double. As you can see in the code, my if for in the variable latas and difvalor because you’re making the mistake: A value of type 'double' can’t…
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answer785
viewsHow to use the value of a Future in flutter
I’m using Flutter to create a mobile app with two collections in the Cloud Firestore, the collection user and the collection person. The collection person stores the information of all persons who…
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answer62
viewsHow to take off Floatingactionbutton from Bottomnavigationbar items?
I’m developing a screen with a floatingactionbutton in the middle of a bottom navigation however, it is very close to the menu items. How do I give a correct spacing? My code: class _NavigationState…
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answer4227
viewsCreate an array list in the flutter
I have two pages. On the first page I want to return a list. I want to insert in this list the values that come from the second page. So the flow is more or less the following: I enter the second…
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answer913
viewsImage in flutter’s Image.network URL does not work on physical device
I made a basic app, because until then, I only used Image.asset() to put picture, now I went to put Image.network() and the URL and it worked on the AVD I created, but when I do the APK and install…
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answer74
viewsHow to multiply Widgets in a list?
Before you start doing the Back-End part of the app I wanted to see what this list style with more items would look like. class ListScreen extends StatefulWidget { @override _ListScreenState…
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answer165
viewsHow to use linter in flutter/Dart to improve code quality?
In flutter/Dart Lint (process that parses the code to identify possible errors.) comes by default with some 'flexible' rules that allows an error code to compile and execute. Such rules can pass up…
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answer833
viewsLayout button in flutter
I’m trying to build a video player. However I’m not getting to leave the button the way I’d like. It’s like I need to "extend" the size of the button so that the intersection point of borderRadius…
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answer200
viewsHow do I list data from a model that receives a JSON but an array in the structure?
The goal here is to list the array tracking, but it presents this error below when I try: ERROR: Exception has occurred. Nosuchmethoderror (Nosuchmethoderror: The method '[]' was called on null.…
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answer332
viewsFlutter - Change one image to another in a short period of time
Everybody, good afternoon, everybody! I have a grid with 2 items set with "on tap" to perform an action. These items have an image coming from /Assets.png and wanted the image to change to another…
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answer124
viewsI cannot validate the current computer time with IF ELSE, on Dart
I’m trying to do a validation on Dart, where my function timevalider() has a variable of type dynamic, where he fits in with what I put in. I’m doing the following assignment time = new…
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answers504
viewsCreating folder that does not erase when uninstall to save backup - Flutter
I am developing a backup system using path_provider, with the following code. // Busca o local que esta o arquivo Directory documentsDirectory = await getApplicationDocumentsDirectory(); final path…
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answers836
viewsCheckbox in the Flutter
I’m trying to create a List, which shows the necessary ingredients, and next to them, a Checkbox, simulating what the user took or not. I tried Checkbox, Checkboxlisttile, but I have no idea what to…
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answers313
viewshow to make this variable have a double value #Dart
If anyone can give me a detailed description, thank you, I’m new to the language import 'dart:io'; void main(){ var saldo = 100; print(' '); print('gostaria de sacar dinheiro?: (y/n)'); String…
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answers73
viewsUse of a _dolarChanged(String text) void function generating an error message in onChanged
I created the following function: void _dolarChanged(String text) { if (text.isEmpty) { _clearAll(); return; } final double dolar = double.parse(text); realController.text = (dolar *…
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answer31
viewsProblems with Splitting in Flutter
Good evening!! I am creating a social network feed with Flutter, and I find myself with a problem in the display of the images. Divider should appear between the two images, however, what is…
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answer135
viewsHow to return a registration layout based on a selected Dropdownmenuitem Flutter option
Good afternoon, everyone! I’m a beginner in development flutter and I’m having a hard time returning a specific registration layout based on the option selected by the user in Dropdownmenuitem.…
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answer232
viewsHow Dart interprets a ()=>{x,y,z} Arrow in lambda/anonymous functions
Have a similar question here (referring to javascript) but I believe that there are different characteristics in the implementation with Dart. Example in Dart: void main() { printName(() => {…
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answer167
viewspageView with a bottomNavigationBar = error
Friends, I’m trying to make a pageView with a bottomNavigationBar, but I’m getting an error that I don’t understand why. In this line: currentIndex: controller.page.round(), the page is coming with…
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answer73
viewsHow to run counter without click event?
How to run the click counter without having to click the button? Type starts app already starts 1, 2, 3... I tried it as follows, but I can’t start the project without the same event. void main()…
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answers303
viewsPath between 2 points with polylines, google maps route
I made an app using flutter where I want to determine a path between two points. I can do it, but the problem is that the line that connects the points A, B doesn’t respect the streets... I use a…
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answer37
viewsHow to make a generation of text without scroll
I am trying to generate text like there in text("500g oats") but I want to generate without that scroll. There is some widget that can do this? import 'package:flutter/material.dart'; class…
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answer260
viewsHow to save given type map or array in firestore?
I tried it this way: createProduto(Produto produto){ Map<String, dynamic> model = { "nome" : produto.nome, "descricao" : produto.descricao, "precoCompra" : produto.precoCompra, "itens" :…
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answers184
viewsNavigation between screens in Flutter
I’m making an app where I need to open navigate to a new screen when I click on some Gridview container, it was working normally when the containers were each on an Inkwell, but the code is getting…
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answers127
viewsHow to pass two variables in a steless with Flutter
Talk people! I’m starting on the flutter! Can you give me a light there? I take 'snapshot' from another screen with Navigator.of(context). push and on this screen Productscone need to pick up the…
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answer142
viewsChange an entire Scaffold body
Hello! I’m trying to finalize an app, but I stopped in a problem. I have a screen with a Scaffold and a action in appBar with widget that returns the date. I would like to know how to update a text…
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answer201
viewsHow do I use http.get() in Flutter WEB?
I’m trying to run a Flutter mobile project on WEB. There is a part that we make a requisition http an endpoint to take a JSON data that is used the following excerpt: final response = await…
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answer207
viewsFlutter Autocompletetextfield with dynamic hintText
Description My App consists of two widgets: The first (Autocompleteinput) is composed of an autocomplete field (Autocompletetextfield) and a button beside it as shown in the following image: When an…
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answer417
viewsHow to place an online symbol inside a flutter image
Hi, I have to put an online symbol inside an image, but I don’t know how to do it, I want something like : All I could do was: As I pass this green ball to image, as in the example up there, my…
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answer163
viewsReturn value 0 or 1 with checkbox (Dart)
(I’m new to language) I have a checkbox to inform if the customer wants to receive (1) the push or not (0). My idea is to create a Dynamic variable (to receive all types) and then convert true=1 and…
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answer317
viewsConfiguration of Flutter web and Firebase
I am trying to make a web application with Flutter Web and in my file index.html pasted the script indicated by google firebase, but when I run the application, it runs for hours "compaling…
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answer352
viewsAnother Exception was thrown: Nosuchmethoderror: The getter 'zipcode' was called on null
I’m making a shipping calculator screen, the code ta all " working" however at the time of running the app and get on the calular screen presents me this Error Follows some Codes. import…
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answer84
viewsConsuming SOAP in Flutter, storing Cookie
Good morning everyone, I’m having a hard time, I need to consume a WS in SOAP, when I use Postman works, but when I try to work with the data in Flutter, it’s not working, I think it’s something in…
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answer185
viewsRadiobutton in flutter with error
I’m having problems with this code, when I run the following error appears: "Unimplemented Handling of Missing Static target". What can it be? How can I solve this problem? import…
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answer70
viewsCreating Listeners in Gridview using a List Flutter
I’m creating a menu with a gridview on the flutter. Shares are on a List: List<Map> actions = [ {"description": "Cadastro", "icon": Icons.people, }, {"description": "Alterar Senha", "icon":…
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answer287
viewsHow to create a reusable dropdownButton in Flutter
I intend to create a dropdown reusable with Flutter, which is capable of receiving different lists of values as an argument. However, I get an error when creating a variable that will store the…
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answer64
viewsStreambuilder does not return value - Flutter
Hello! I’m trying to return location values with StreamBuilder, but I’m not succeeding. In debug, it doesn’t even run Builder. I can’t find the problem. Here I create the Streambuilder, to bring the…
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answer355
viewsSeparating Flutter components
Inside a alertDialog I created a column with the checkbox and then a Row with two Flatbutton, however they are side by side and I need them to be below the checkbox. Code AlertDialog( ... actions:…
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answer49
viewsAPI call returning delayed data
What’s wrong with my function? Because, the data called in the second api returns with enough delay. How do I load the screen only after the return of the second API? var os = new List<OS>();…
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answers46
viewsHow to implement Voidcallback in a List of Items to list in a Gridview?
I tried to follow the tutorial of this link http://www.macoratti.net/19/07/flut_gridv1.htm because it has a list of items in gridview closer than I want to use. And then I tried to add an option to…
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answer98
viewsTabbarview with card generating error while loading data into flutter
Good morning, I’m starting now in the flutter world and I’m mounting a Tabbarview card with data coming from a bank. I’m putting it inside Listview so I can separate it into tabs and load the data…
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answers82
viewsProblem with value animation in Flutter
I have a problem with a numerical transition animation. I wanted the animation to always continue from the last generated number, but is always repeating the first value transition made I’ve looked…
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answers264
viewsListview doesn’t update on the screen!
I’d like to ask for a beginner’s help on Flutter/Dart. I’m programming an app to add cards that represent real estate, and each card represents a property within a Listview. But I can’t update…
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answer232
viewsWhere am I wrong in cheering up by showing and hiding widgets in the flutter?
I made a list divided into two gridview because I wanted only the first 3 items to be displayed and with a button to display more items later. I don’t know if it was the right way to do it but it…
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answer48
viewsDoubt Flutter - List
Good morning, you guys! I am doubtful to bring the elements of a list. Could someone assist me? I am new to the flutter. What am I doing: I have a list who is called listed that brings me the…
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answer294
viewsError when connecting API to Flutter (Dio)
Good afternoon! I’m trying to learn how to use the Dio to integrate an API that I am also developing and for this I tried to carry out a simple test. I simply tried to make a print on the terminal…
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answer81
viewsField recording as Null in Firestore Flutter
I’m trying to record a document inside another document (nested Documents) in Flutter with Firestore. The model is a property that has some fields, and next to the fields a collection of comforts,…
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answer54
viewsUpdate method with flutter and sqlite generating error
Good morning, I am updating to sqlite with Flutter and am having the following error: NoSuchMethodError: The method 'update' was called on null. I built the code according to the documentation where…
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answer290
viewsHow do I update a Widget via a controller in an Onchanged field?
I cannot update a Text widget that should show the sum of two Textformfield as long as someone is changing it (Onchanged). What could I be doing wrong? (I’ve put Setstate everywhere and nothing has…
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answer260
viewsCreating flutter tables generating error in such table
I’m having a problem where I’m not being able to create more than one table in the fluuter sqlite. When trying to create a table if the database has already been created generates the error no such…