Widget is the heart of Flutter. If you have any prior experience using Flutter, you probably know the three different types of widgets that exist: The Stateful widget, the Stateless widget, and the Inherited widget. But, if you are a Flutter beginner, it is important that you know that the code of the screen lies either in a Stateful or Stateless widget. And therefore, these two types are majorly important for you to implement Flutter development. The next question that will pass through your mind will be, what to opt for between Stateless and Stateful widget? Well, we are here for help.
In this write-up, we will go into the details of Stateful Vs Stateless widget and not much into the Inherited widget. However, for your information, let me just clarify that the Inherited widget is a combination of both, Stateful and Stateless. If you replace an Inherited widget with a new one, all the older ones will be replaced. So, yeah, that’s it about the Inherited widget; let us now begin with the topic, Stateful vs Stateless widget in Flutter.
To start with the basics,
What is a State?
In simple words, a State is an information that prevails in the app memory during its execution. The properties that are fed in at the time of the creation of the widget can be changed during its implementation or through its lifetime. The properties or the parameters include UI elements such as buttons, text fonts, icons, animation, etc.
Further, let’s look into the details of each widget type, Stateful Vs Stateless widget for Flutter development.
Stateless widget:
A stateless widget simply means the properties are immutable. The properties can change only when you set a new instance for the particular widget; otherwise, it remains constant during the application’s runtime.
A Stateless widget can not rebuild itself; it can only be done externally. It is of great use when the UI elements used in the mobile application development building are not dependent on anything but configuration information. Examples of Stateless widgets are IconButton, Variables, and Text.
A Stateless widget allows the “build” method to enact only once that too when the widget parameters are executed.
import ‘package:flutter/material.dart’;
void main() => DoApp(KodyApp());
class KodyApp extends StatelessWidget {
@override
Widget build(BuildContext context) {
return Container();
}
}
The above code suggests the execution of a stateless widget named KodyApp, which will be executed by DoApp. KodyApp contains a build function that is overridden and uses the BuildContext parameter.
Stateful Widget:
Stateful widgets are mutable, meaning that their properties can be changed during runtime. They are opposite to the Stateless widget and are also user interactive. The mutable state is stored separately in a State object.
The widget state can be changed even after they are built, and it allows you to input different sets of variables, inputs, or change the data. The Stateful widget accesses a method named setState, which instigates the changes in the Stateful widget.
Stateful widgets are dynamic and are triggered when the user interacts. Examples of Stateful widgets are RadioButton, Slider, InkWell, Form, and
TextField.import ‘package:flutter/material.dart’;
void main() => DoApp(KodyApp());
class KodyApp extends StatefulWidget {
@override
_KodyAppState createState() => _KodyAppState();
}
class _KodyAppState extends State<KodyApp> {
@override
Widget build(BuildContext context) {
return Container();
}
}
In this code container, the name of the Stateful widget is KodyApp, which is initiated by DoApp(). The Stateful widget is overridden by the createState() function, which is mutable. The _KodyAppState class is responsible for managing the widget changes. And inside this class lies the BuildContext that calls the app’s UI.
Because the stateful widgets are mutable, the build function is called multiple times, and the UI is created with all the changes in the UI. The stateful widget is dynamic and therefore used when the UI components need to change according to the user interaction.
Why is it important for a Flutter app development company to implement a State in a widget?
We all will agree that the front-end of the application is built for user interaction. A State represents the front-end of the application, be it local or the state of the whole app.
When there is less complexity involved, it is pretty easy to manage States across the app, but it becomes a hustle to manage with applications involving much complexity. And hence, the hired Flutter app developers implement respective States in the flutter app.
When to use a Stateful Vs Stateless widget for Flutter development?
Well, yes, as much as it is important to know the difference between Stateless and Stateful widgets, it is equally important to know when to use between the two. Here are the conditions when you should opt for either of the widget types.
- If the UI elements of the widget are dependent on the parent widget, which further lies in a constructor, go for the Stateless widget.
- If the elements change upon user interaction and are independent of the parent, opt for the Stateful widget.
Can a Stateless widget become stateful if the container has a Stateful widget?
Well, technically, it doesn’t. The parent widget is unaware of the child’s widget state, and both of them manage their states on their own.
To conclude,
Stateless and Stateful widget comparison:
| Stateless widget | Stateful widget |
| They are static widgets; they are updated only when initialized. | They are dynamic in nature. |
| It is not dependent on data changes or behavior changes. | It is dependent and changes when the user interacts. |
| Examples are Text, Icons, or a RaisedButton. | Examples are Checkbox, RadioButton, or Slider. |
| Doesn’t include a setState(). | It has an internal setState(). |
| Can not be updated during the application’s runtime. An external event is necessary for the trigger. | It can be updated during the runtime. |
Almost there!
The topic, Stateless Vs Stateful widgets might be confusing for a beginner, but I hope we have cleared your doubts successfully. The implementation between the two of the states is completely based on your choice and the development team’s suggestions. We at Kody Technolab, ace the game of Flutter app development services and provide full-stack development packages. You may connect with us to know any more details about the topic. Ciao!
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