Questions tagged [flutter]
Use this tag for questions about the Flutter cross-platform UI toolkit. If your question is platform-specific, tag the platform as well (e.g., [android], [ios], etc.). You may also wish to include the [dart] tag for coding questions.
190,328
questions
747
votes
30
answers
352k
views
How can I remove the debug banner in Flutter?
I'm using flutter screenshot and I expected the screenshot to not have a banner, but it has.
Note that I get a not supported for emulator message for profile and release mode.
- 29.3k
611
votes
34
answers
601k
views
How do I use hexadecimal color strings in Flutter?
How do I convert a hexadecimal color string like #b74093 to a Color in Flutter?
I want to use a HEX color code in Dart.
555
votes
38
answers
757k
views
Create a rounded button / button with border-radius in Flutter
I'm currently developing an Android app in Flutter. How can I add a rounded button?
- 10.7k
550
votes
14
answers
557k
views
How to change the application launcher icon on Flutter?
When I create an app with a flutter create command, the flutter logo is used as an application icon for both platforms.
If I want to change the app icon, shall I go to both platforms directories and ...
- 8,809
542
votes
18
answers
930k
views
How can I add a border to a widget in Flutter?
I'm using Flutter and I'd like to add a border to a widget (in this case, a Text widget).
I tried TextStyle and Text, but I didn't see how to add a border.
- 113k
505
votes
23
answers
479k
views
I am getting error "cmdline-tools component is missing" after installing Flutter and Android Studio... I added the Android SDK. How can I solve them?
Android toolchain - I develop for Android devices (Android SDK version 30.0.3):
X cmdline-tools component is missing
Run `path/to/sdkmanager --install "cmdline-tools;latest"`
See https://...
- 5,053
486
votes
27
answers
274k
views
How do you build a Singleton in Dart?
The singleton pattern ensures only one instance of a class is ever created. How do I build this in Dart?
- 113k
480
votes
34
answers
438k
views
How to change package name in flutter?
Is there any way to change Package Name of Flutter project?
I want to change package name and application name in flutter project.
- 5,937
472
votes
33
answers
333k
views
How can I dismiss the on screen keyboard?
I am collecting user input with a TextFormField and when the user presses a FloatingActionButton indicating they are done, I want to dismiss the on screen keyboard.
How do I make the keyboard go away ...
- 111k
468
votes
28
answers
374k
views
No Firebase App '[DEFAULT]' has been created - call Firebase.initializeApp() in Flutter and Firebase
I am building a Flutter application and I have integrated Firebase, but I keep getting this error when I click on a button either to register, login, or logout. I have seen other people have asked the ...
- 5,690
449
votes
20
answers
258k
views
How do you detect the host platform from Dart code?
For UI that should differ slightly on iOS and Android, i.e. on different platforms, there must be a way to detect which one the app is running on, but I couldn't find it in the docs. What is it?
- 6,545
445
votes
40
answers
467k
views
How to run CocoaPods on Apple Silicon (M1)
I have a Flutter project that I'm trying to run on iOS. It runs normally on my Intel-based Mac, but on my new Apple Silicon-based M1 Mac it fails to install pods.
LoadError - dlsym(0x7f8926035eb0, ...
- 11.8k
436
votes
24
answers
503k
views
Flutter - Wrap text on overflow, like insert ellipsis or fade
I'm trying to create a line in which center text has a maximum size, and if the text content is too large, it fits in size.
I insert the TextOverflow.ellipsis property to shorten the text and ...
- 12.5k
424
votes
19
answers
469k
views
How to do Rounded Corners Image in Flutter
I am using Flutter to make a list of information about movies. Now I want the cover image on the left to be a rounded corners picture. I did the following, but it didn’t work. Thanks!
getItem(var ...
- 4,952
412
votes
27
answers
468k
views
How to create number input field in Flutter?
I'm unable to find a way to create an input field in Flutter that would open up a numeric keyboard and should take numeric input only. Is this possible with Flutter material widgets? Some GitHub ...
- 26.1k
390
votes
20
answers
335k
views
How can I change the app display name build with Flutter?
I have created the app using Flutter create testapp.
Now, I want to change the app name from "testapp" to "My Trips Tracker". How can I do that?
I have tried changing from the ...
- 4,392
389
votes
18
answers
261k
views
How to add a ListView to a Column in Flutter?
I'm trying to construct a simple login page for my Flutter app. I've successfully built the TextFields and log in/Sign in buttons. I want to add a horizontal ListView. When I run the code my ...
- 8,383
383
votes
24
answers
205k
views
Waiting for another flutter command to release the startup lock
When I run my flutter application it show
Waiting for another flutter command to release the startup lock
this messages and not proceed further.
- 25.6k
374
votes
35
answers
432k
views
Dart SDK is not configured
I installed Flutter and set up Android Studio. Then I cloned an example of flutter on GitHub (https://github.com/flutter/flutter) and launched it in Android Studio, but it warns me "Dart SDK is ...
- 3,751
369
votes
62
answers
569k
views
Message "flutter run: No connected devices"
I am trying to create a sample application with Flutter (fresh installation). Android Studio is also installed (fresh installation).
Here is the output of flutter run
flutter run
No connected devices.
...
- 15.3k
365
votes
20
answers
302k
views
How do I supply an initial value to a text field?
I'd like to supply an initial value to a text field and redraw it with an empty value to clear the text. What's the best approach to do that with Flutter's APIs?
- 113k
362
votes
27
answers
337k
views
Flutter : How to change Android minSdkVersion in Flutter Project?
I was trying to start a flutter project for an App using Bluetooth to communicate. For that, I was using flutter blue.
Unfortunately, when trying to run (on an Android device) the first example I ...
- 10.6k
360
votes
32
answers
583k
views
How to use conditional statement within child attribute of a Flutter Widget (Center Widget)
So far whenever I needed to use a conditional statement within a Widget I have done the following (Using Center and Containers as simplified dummy examples):
new Center(
child: condition == true ? ...
- 4,897
354
votes
16
answers
147k
views
Scaffold.of() called with a context that does not contain a Scaffold
As you can see, my button is inside the Scaffold's body. But I get this exception:
Scaffold.of() called with a context that does not contain a Scaffold.
import 'package:flutter/material.dart';
void ...
- 12.2k
345
votes
18
answers
374k
views
Sizing elements to percentage of screen width/height
Is there a simple (non-LayoutBuilder) way to size an element relative to screen size (width/height)? For example: how do I set the width of a CardView to be 65% of the screen width.
It can't be done ...
- 6,418
345
votes
8
answers
234k
views
Passing data to StatefulWidget and accessing it in its state in Flutter
I have 2 screens in my Flutter app: a list of records and a screen for creating and editing records.
If I pass an object to the second screen that means I am going to edit this and if I pass null it ...
- 19.9k
343
votes
25
answers
523k
views
Error:(1, 0) Plugin with id 'com.android.application' not found
This is my first attempt at Android Studio. I installed 0.8.0 and updated to 0.8.2. As soon as a project is created I get the error message:
Error:(1, 0) Plugin with id 'com.android.application' ...
- 3,439
333
votes
24
answers
216k
views
Flutter: how to prevent device orientation changes and force portrait?
I would like to prevent my application from changing its orientation and force the layout to stick to "portrait".
In the main.dart, I put:
void main(){
SystemChrome.setPreferredOrientations([
...
- 6,897
330
votes
14
answers
118k
views
flutter doctor --android-licenses gives a java error
Exception in thread "main" java.lang.NoClassDefFoundError: javax/xml/bind/annotation/XmlSchema
at com.android.repository.api.SchemaModule$SchemaModuleVersion.<init>(SchemaModule.java:156)
...
- 3,321
326
votes
27
answers
293k
views
Vertical viewport was given unbounded height
This is my code:
@override
Widget build(BuildContext context) {
return new Material(
color: Colors.deepPurpleAccent,
child: new Column(
mainAxisAlignment: MainAxisAlignment.center,
...
- 6,229
326
votes
16
answers
132k
views
Yellow lines under Text Widgets in Flutter?
The main app screen doesn't have this issue, all the texts show up as they should.
However, in the new screen, all the text widget have some weird yellow line / double-line underneath.
Any ideas on ...
- 4,871
322
votes
17
answers
330k
views
How do I disable a Button in Flutter?
I'm having trouble figuring out how to set the enabled state of a button in Flutter.
From the docs, it says to set onPressed to null to disable a button, and give it a value to enable it. This is fine ...
- 3,950
319
votes
15
answers
314k
views
Flutter: Run method on Widget build complete
I would like to be able to run functions once a Widget has finished building/loading but I am unsure how.
My current use case is to check if a user is authenticated and if not, redirect to a login ...
- 3,234
317
votes
16
answers
354k
views
How to show/hide widgets programmatically in Flutter
In Android, every single View subclass has a setVisibility() method that allows you modify the visibility of a View object
There are 3 options of setting the visibility:
Visible: Renders the View ...
- 5,836
317
votes
6
answers
56k
views
What is the difference between functions and classes to create reusable widgets?
I have realized that it is possible to create widgets using plain functions instead of subclassing StatelessWidget. An example would be this:
Widget function({ String title, VoidCallback callback }) ...
- 258k
314
votes
12
answers
355k
views
Flutter: how to make a TextField with HintText but no Underline?
This is what I'm trying to make:
In the Flutter docs for Text Fields (https://flutter.io/text-input/) it says you can remove the underline by passing null to the decoration. However, that also gets ...
- 3,254
309
votes
25
answers
364k
views
Module was compiled with an incompatible version of Kotlin. The binary version of its metadata is 1.5.1, expected version is 1.1.15
In Stripe, my client wants email and cardholder name, but the Stripe payment UI doesn't provide that option in com.stripe.android.view.CardMultilineWidget. I wanted to give it a try with the latest ...
- 3,213
308
votes
11
answers
159k
views
TextField inside of Row causes layout exception: Unable to calculate size
I’m getting a rendering exception that I don’t understand how to fix. I’m attempting to create a column that has 3 rows.
Row [Image]
Row [TextField ]
Row [Buttons]
Here is my code to build the ...
- 4,397
305
votes
9
answers
264k
views
setState() or markNeedsBuild called during build
class MyHome extends StatefulWidget {
@override
State<StatefulWidget> createState() => new MyHomePage2();
}
class MyHomePage2 extends State<MyHome> {
List items = new List();
...
- 3,587