dart
What is the purpose of a factory method in flutter/dart?
You have it correct! You can read more about factory constructors here: https://dart.dev/guides/language/language-tour#factory-constructors
Error: The argument type ‘String?’ can’t be assigned to the parameter type ‘String’ because ‘String?’ is nullable and ‘String’ isn’t [duplicate]
The error is caused by the null safety feature in Dart, see https://dart.dev/null-safety. The result of method stdin.readLineSync() is String?, i.e. it may be a String, or it may be null. The method int.parse() requires a (non-null) String. You should check that the user gave some input, then you can assert that the value is … Read more
How to find unused flutter classes in Android Studio or Visual Studio Code
Dart code metrics https://pub.dev/packages/dart_code_metrics supports finding unused files for flutter. As commented by in 2023, unfortunately, it is not free anymore https://dcm.dev/pricing/. To purchase a license, see their website. install: flutter pub add –dev dart_code_metrics run “flutter packages get” or use your IDE to “Pub get”. run: flutter pub run dart_code_metrics:metrics check-unused-files lib result: Unused … Read more
Unsupported operation: _Namespace while using dart io on web
dart:io can not be used in web projects. dart:html has some limited file API (limited to what the browser allows). Dart in the browser can not do anything the browser does not provide. (Not sure why Günter didn’t put this as an answer…)
How to access map keys through index? Dart
you can get it like this var element = dartques.values.elementAt(0); also for Dart 2.7+ you can write extension function extension GetByKeyIndex on Map { elementAt(int index) => this.values.elementAt(index); } var element = dartques.elementAt(1);
How to remove a card’s inner padding in flutter?
I just want to leave a full code removing the default margin to make it clear Card( margin: EdgeInsets.zero, clipBehavior: Clip.antiAlias, shape: RoundedRectangleBorder( borderRadius: BorderRadius.circular(8.0), ), elevation: 4, child: Image.network( model.item.image, width: 20, height: 200, alignment: Alignment.center, fit: BoxFit.cover, ),
flutter open images from file path
The Image class has a file constructor for that https://api.flutter.dev/flutter/widgets/Image/Image.file.html Image.file(File(path))
How to play sound on button press
Add audioplayers as a dependency and your audio file to pubspec.yaml file like this: dependencies: audioplayers: ^1.0.1 flutter: assets: – assets/audio/my_audio.mp3 Full code (Null-safe): class _HomePageState extends State<HomePage> { @override Widget build(BuildContext context) { return Scaffold( body: ElevatedButton( onPressed: () => AudioPlayer().play(AssetSource(‘audio/my_audio.mp3’)); child: Text(‘Play’), ), ); } }
How to solve “A RenderFlex overflowed by 143 pixels on the right.” error in text?
Just Wrap you – Card with –Flexible Widget. Row( children: <Widget>[ Flexible( child: Card( child: Column( crossAxisAlignment: CrossAxisAlignment.start, children: <Widget>[ Text(“Item name mmmasdaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaammmmmm”), SizedBox(height: 15.0,), Text( “Discount mmmmmmmm”, ), SizedBox(height: 5.0,), Text( “Price ,mmmmmmmmmdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfdgfmmmmmmmmm”, ) ], ), ), ), ], ),