I tried mezonis approach with the Activator and it works. But it is an expensive approach as it uses mirrors, which requires you to use “mirrorsUsed” if you don’t want to have a 2-4MB js file. This morning I had the idea to use a generic typedef as generator and thus get rid of reflection: … Read more
It is a small performance improvement, but it can add up in larger apps or apps where the view is rebuilt often for example because of animations. const reduces the required work for the Garbage Collector. You can enable some linter rules in analysis_options.yaml that tell you when you should add const because it’s not … Read more
In my case i had code like this (in class state) final GlobalKey<ScaffoldState> _scaffoldKey = new GlobalKey<ScaffoldState>(); void showInSnackBar(String value) { _scaffoldKey.currentState.showSnackBar(new SnackBar(content: new Text(value))); } but i didn’t setup the key for scaffold. so when i add key: _scaffoldKey @override Widget build(BuildContext context) { return new Scaffold( key: _scaffoldKey, body: new SafeArea( snackbar start … Read more
build() can and usually will be called more than once and every time a new Timer.periodic is created. You need to move that code out of build() like import ‘dart:async’; Timer? timer; @override void initState() { super.initState(); timer = Timer.periodic(Duration(seconds: 15), (Timer t) => checkForNewSharedLists()); } @override void dispose() { timer?.cancel(); super.dispose(); } Even better … Read more
The easiest way I know of is to use Iterable.expand() with an identity function. expand() takes each element of an Iterable, performs a function on it that returns an iterable (the “expand” part), and then concatenates the results. In other languages it may be known as flatMap. So by using an identity function, expand will … Read more
There’s no notion of “Starts from max/min size”. The thing is, ContrainedBox only add constraints to it’s child. But in the end, it doesn’t pick a size. If you want your child to hit minSize, then they have to not expend. Which translate into not having a width/height of double.INFINITY. Fact is that double.INFINITY is … Read more
TDLR: imports file only using import ‘package:myApp/path/myFile.dart’; Never with import ‘./myFile.dart’; This is due to how dart resolves imports. You may have a single source file, but during builds, there is some kind of duplicates. Let’s say you’re working on ‘myApp’. To import a file, you could do both : import ‘relativePath/myFile.dart’ import ‘package:myApp/path2/myFile.dart’ You’d … Read more
If you have something like this: class MyClass { String data; MyClass(this.data); @override String toString() { return data; } } MyClass myObject = new MyClass(“someData”); print(myObject); // outputs “someData”, not ‘Instance of MyClass’ I think this might be what you are looking for.
If you’re using shared_preferences 0.2.4 and above, use setMockInitialValues: SharedPreferences.setMockInitialValues({}); // set initial values here if desired For earlier versions you can do it manually: const MethodChannel(‘plugins.flutter.io/shared_preferences’) .setMockMethodCallHandler((MethodCall methodCall) async { if (methodCall.method == ‘getAll’) { return <String, dynamic>{}; // set initial values here if desired } return null; });
In Dart the as operator doesn’t allow you to change the actual structure of an Object, it just allows you to provide a hint that an object might have a more specific type. For example, if you had a dog and an animal class you could use as to specify that your animal is actually … Read more