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
The web server’s Content-Type header is Content-Type: text/html. Note that isn’t including a charset suffix. It should be saying Content-Type: text/html; charset=utf-8. The package:http client looks for this charset when asked to decode to characters. If it’s missing it defaults to LATIN1 (not utf-8). As you’ve seen, setting the headers on the Request doesn’t help, … Read more
I was with the same problem and I found the following solution after a long time of searching, just so it will work: GoogleMap( gestureRecognizers: <Factory<OneSequenceGestureRecognizer>>[ new Factory<OneSequenceGestureRecognizer>(() => new EagerGestureRecognizer(),), ].toSet(),) The reason is that the EagerGestureRecognizer is a gesture recognizer that eagerly claims victory in all gesture arenas. Reference: Manage gestures priority between … Read more
Here’s a sketch of how to implement a Speed dial using FloatingActionButton. import ‘package:flutter/material.dart’; import ‘dart:math’ as math; void main() { runApp(new MyApp()); } class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return new MaterialApp( home: new MyHomePage(), ); } } class MyHomePage extends StatefulWidget { @override State createState() => new MyHomePageState(); } … Read more
Could you create your keys “by hand” and use static/constant values? e.g. … import ‘package:flutter/widgets.dart’; class RIKeys { static final riKey1 = const Key(‘__RIKEY1__’); static final riKey2 = const Key(‘__RIKEY2__’); static final riKey3 = const Key(‘__RIKEY3__’); } then in … body: new TabBarView( children: [ new RefreshIndicator(new RefreshIndicator( // Use the Manual Static Value instead … Read more
context.read is not allowed inside build because it is very dangerous to use there, and there are much better solutions available. Provider.of is allowed in build for backward-compatibility. Overall, the reasoning behind why context.read is not allowed inside build is explained in its documentation: DON’T call [read] inside build if the value is used only … Read more
I would probably use a BoxDecoration with a DecorationImage. You can use the alignment and fit properties to determine how your image is cropped. You can use an AspectRatio widget if you don’t want to hard code a height on the Container. import ‘package:flutter/material.dart’; void main() { runApp(new MaterialApp( home: new MyHomePage(), )); } class … Read more
Navigate to a new screen: Navigator.of(context).push(MaterialPageRoute(builder: (context) => NewScreen())); where context is the BuildContext of a widget and NewScreen is the name of the second widget layout. Code main.dart import ‘package:flutter/material.dart’; void main() => runApp(MyApp()); class MyApp extends StatelessWidget { @override Widget build(BuildContext context) { return MaterialApp( title: ‘Flutter Demo’, theme: ThemeData(primarySwatch: Colors.blue), home: HomeScreen(), … Read more
This code Future<List<String>> readHeaderData() async { List<String> l = new List(); List<String> files = await readHeaders(); // Gets filenames files.forEach((filename) async { final file = await File(filename); String contents = await file.readAsString(); User user = User.fromJson(json.decode(contents)); String name = user.NameLast + “, ” + user.NameFirst; print(name); l.add(name); } return l; } returns the list l … Read more
You’re looking for “identical”, which will check if 2 instances are the same. identical(this, other); A more detailed example? class Person { String ssn; String name; Person(this.ssn, this.name); // Define that two persons are equal if their SSNs are equal bool operator ==(Person other) { return (other.ssn == ssn); } } main() { var bob … Read more