This all becomes a lot easier to understand when you stop thinking there are a lot of classes and start thinking there are only three jobs that need to be done. But, after Remi kindly took a lot of his time to help me understand (and didn’t laugh at me) I realized something. When someone first looks at this, they often get intimidated. I mean, you could make a word cloud out of all the classes you can use with it: Provider looks daunting when you first dig into it. If you don’t understand, no explanation can help. If you understand, no explanation is necessary. You remember InheritedWidget, right? I like to call it “Flutter’s Monad”: In short, Provider is like a way to use InheritedWidget that humans can understand.
They even said so in their talk, “Pragmatic State Management”, at I/O 2019 In fact, they recommend Remi Rousselet’s Provider over their own version of it, which was called Package Provider.
We had asked him if the Flutter team recommended any one method of State Management approach over others, and yes, they do. That’s a direct quote from Chris, from when he was on #HumpDayQandA. – Chris Sells – Product Manager, Flutter. First parameter is, context which is the BuildContext of this builder, then viewModel which will give you access to the properties and methods inside the class CounterViewModel, and the optional child parameter which you can use to avoid rebuild.Īlso, as you can see we use Provider.of(context,listen: false).incrementCounter with listen:false, if listen is true then the whole build() method would get called.Provider is the recommended way to do State Management for apps of all sizes. The Consumer widget has a builder function that is called whenever the ChangeNotifierProvider gets notified of any changes in the object. To access the counter getter of the class CounterViewModel, we need to use a Consumer widget. Import 'package:flutter/material.dart' import 'package:provider/provider.dart' class MyHomePage extends StatelessWidget Adding Provider To FlutterĪfter creating a project, navigate to the pubspec.yaml file and add the following: In the Covid Tracker application I use provider for state management and MVVM architecture for the whole application. In simple terms, provider is a wrapper around Inherited Widgets, which was explained in the previous tutorial Using Inherited Widgets In Flutter.įor an example about provider, you can check the following application, Covid Tracker. To solve the above issues, there are many different state management packages one of them is provider which was created by Remi Rousselet.
#Flutter provider code#
The other problem with setState() is that it does not help in seperation of concern which basically means seperation your code into different layers(presentation, domain, data). The problem with setState() is that it will issue a build for the parent widget and all children widget, no matter if the children widgets are StatefulWidgets or StatelessWidgets. Now invoking setState() will notify the framework that the internal state of this object has changed, which basically means that a rebuild will happen with the updated values.
#Flutter provider how to#
In this article, we will explain what is provider, check different provider type used and give an example on how to use it in a Flutter application.Īs you may have seen in previous tutorials, I have used setState() multiple times.
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