#FLUTTER PROVIDER UPDATE#
#FLUTTER PROVIDER CODE#

If the blue button is clicked to update the value of Box1 which is highlighted with red color and setState is called on the event, all widgets listed here are rebuilt.

All widgets are defined in the same class. It takes longer to complete to rebuild all widgets than to rebuild only one widget. If the parent widget is rebuilt all child widgets are rebuilt even if the rebuild is not necessary for some of them. It means that setState needs to be called in the widget or parent widget. Why is provider necessary in the first place? When one of the values on a view needs to change, its item needs to be rebuilt. ChangeNorifier that have more than 2 properties.It also provides additional advantages like lazy-loading, easier allocation/disposal of resources and increased scalability in terms of handling complex state components as part of bigger applications. When using ChangeNotifierProvider, use the correct option of create or value based on if it’s an existing value or creating the provider value for the first time.īy making optimized use of the provider package, you can effectively manage state in your applications with less boilerplate.When using Consumer widget, use the child option to mark part of the independent widget tree which need not rebuild.Using Consumer widget, consume at the specific level in order to avoid rebuilding of the entire tree.Using Provider.of() to consume data, listen to changes only if you need to, otherwise use listen:false.Provide only at the needed level, instead of providing everything at the top level.When making use of the provider package for state management in your application, it is advisable to keep a note of the following best practices for building an optimized solution:

#FLUTTER PROVIDER CODE#

You can find the complete code for this example at the following git repository. To listen to changes in the data at any lower level.To produce changes to the data by updating state through provided methods at any lower level avoiding need for passing callbacks through intermediate levels.To consume the data at any lower level without any intermediate dependencies.Thus by making use of the various classes of the Provider package, we are able to provide data at the top level of the widget tree and be able: Create is called only once in State.initState.Provider is the equivalent of a State.initState combined with State.dispose.It does not notify changes but only a simple way used to avoid making a StatefulWidget. It takes a value and exposes it, whatever the value is. In this blog example, we will look at using the below provider classes which cater to the state management requirements to give a seamless flow. Only the listening widget should get the change and rebuild.Instead of traversing through each intermediate level, in order to pass the data and rebuild the subtree.Need for the widgets to subscribe to the state and listen to changes.Provider is a wrapper around InheritedWidget that makes it easier to use with less boilerplate code. In this blog, we will be looking at using the Provider package for State Management in Flutter, this being the Google recommended approach.

In the last blog and webinar on State Management in Flutter, we learned about managing state using Stateful widgets and also saw how this can become difficult to manage as the complexity of the application increases.

Flutter provider