Flutter Mobile Development · درس

عناصر Stateless مقابل Stateful

افهم الفروقات الأساسية بين StatelessWidget وStatefulWidget، وتعلّم متى وكيف تستخدم كلًا منهما لبناء واجهات مستخدم ديناميكية

عناصر Stateless مقابل Stateful درس مجاني في Flutter Mobile Development على CoddyKit. هذا هو الدرس 1 من أصل 4. يمكنك قراءة الدرس كاملاً أدناه مجاناً — ثم تمرن عليه مباشرة في المتصفح باستخدام محرر أكواد مدمج ومدرس ذكاء اصطناعي متاح 24/7. هذا الدرس جزء من مسار التعلم في Flutter Mobile Development، وتقدمك يتزامن عبر الويب وتطبيق CoddyKit. تتضمن دورة Flutter Mobile Development 4 دروس في المجموع.

بعض أجزاء هذا الدرس لم تُترجم بعد وتظهر باللغة الإنجليزية.

Widgets: The Building Blocks

Flutter UIs are built entirely from widgets. Think of them as LEGO bricks! Everything you see on screen – text, buttons, even layout containers — is a widget.

Widgets describe how your app's UI should look given its current configuration and state. There are two main types of widgets you'll encounter:

StatelessWidget
StatefulWidget

StatelessWidget: Static UI

A StatelessWidget is a widget that does not change its appearance or behavior over time. Once it's built, it stays the same.

It doesn't have any internal "state" to manage.
Its properties are immutable (cannot be changed after creation).
It's perfect for displaying static content like text, icons, or images that don't need to react to user input or data changes.

Simple StatelessWidget

Here's a basic StatelessWidget that displays a welcome message. Notice how its content is fixed.

Run this code to see a static "Hello, CoddyKit!" message.

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Stateless Demo'),
        ),
        body: const Center(
          child: Text(
            'Hello, CoddyKit!',
            style: TextStyle(fontSize: 24),
          ),
        ),
      ),
    );
  }
}

When to Go Stateless

Use a StatelessWidget when:

The widget's appearance depends only on its own configuration parameters (passed in its constructor).
It doesn't need to respond to user interactions (like taps) or internal data changes.
Examples: Text, Icon, Image, AppBar, Padding, Row, Column.

These widgets are efficient because Flutter doesn't need to rebuild them if their parent changes, unless their properties explicitly change.

StatefulWidget: Dynamic UI

A StatefulWidget is a widget that can change its appearance and behavior over time, reacting to user input or data changes.

It has internal "state" that can be modified.
When its state changes, the widget rebuilds to reflect the new state.
It's perfect for interactive elements like checkboxes, sliders, or dynamic lists.

Updating UI with setState()

To make a StatefulWidget dynamic, you modify its internal state. When the state changes, you must call the setState() method.

Calling setState() tells Flutter that the internal state of this widget has changed, and it needs to rebuild the UI to reflect the new state.

Without setState(), your state might change, but the UI won't update!

Interactive StatefulWidget

Let's build a simple counter app using a StatefulWidget. Tap the button to increment the number.

Observe how setState() is used to update the _counter variable and rebuild the UI.

import 'package:flutter/material.dart';

void main() {
  runApp(const MyApp());
}

class MyApp extends StatelessWidget {
  const MyApp({super.key});

  @override
  Widget build(BuildContext context) {
    return MaterialApp(
      home: Scaffold(
        appBar: AppBar(
          title: const Text('Stateful Demo'),
        ),
        body: const Center(
          child: CounterWidget(),
        ),
      ),
    );
  }
}

class CounterWidget extends StatefulWidget {
  const CounterWidget({super.key});

  @override
  State<CounterWidget> createState() => _CounterWidgetState();
}

class _CounterWidgetState extends State<CounterWidget> {
  int _counter = 0; // This is the mutable state

  void _incrementCounter() {
    setState(() {
      _counter++; // Update state
    });
  }

  @override
  Widget build(BuildContext context) {
    return Column(
      mainAxisAlignment: MainAxisAlignment.center,
      children: <Widget>[
        Text(
          'Count: $_counter',
          style: const TextStyle(fontSize: 32),
        ),
        const SizedBox(height: 20),
        ElevatedButton(
          onPressed: _incrementCounter,
          child: const Text('Increment'),
        ),
      ],
    );
  }
}

StatefulWidget's Journey

StatefulWidgets go through a lifecycle. Key moments include:

createState(): Creates the mutable state object.
initState(): Called once when the widget is inserted into the widget tree. Good for one-time setup.
build(): Called every time the widget needs to display its UI, typically after setState().
dispose(): Called when the widget is removed from the tree. Good for cleaning up resources.

Understanding these helps manage complex interactions.

Choosing the Right Widget

Here's a quick comparison to help you decide:

StatelessWidget:
- Immutable properties.
- Doesn't change after creation.
- No internal state.
- Efficient for static content.
StatefulWidget:
- Mutable state (managed by a `State` object).
- Can change dynamically.
- Responds to user interaction/data.
- Uses setState() to trigger rebuilds.

Most widgets start as stateless; only make them stateful if they truly need to change dynamically.

Widget Type Challenge

You are building a Flutter app. Which type of widget would you primarily use for a simple icon that, when tapped, changes its color?

Recap: Dynamic vs. Static

Great job! You've learned the fundamental difference between StatelessWidget and StatefulWidget.

StatelessWidgets are for static UI elements that don't change after they're built.
StatefulWidgets are for dynamic UI elements that need to react to interactions or data changes, using setState() to update their appearance.

Choosing the right widget type is crucial for building efficient and maintainable Flutter applications. In the next lesson, we'll dive into basic layout widgets!

الأسئلة الشائعة

هل درس «عناصر Stateless مقابل Stateful» مجاني؟

نعم — نص درس «عناصر Stateless مقابل Stateful» كامل متاح مجاناً هنا على الويب. لتمرينه بشكل تفاعلي (محرر أكواد مدمج ومدرس ذكاء اصطناعي متاح 24/7) وفتح باقي دورة Flutter Mobile Development، انتقل إلى CoddyKit PRO. تتضمن دورة Flutter Mobile Development 4 دروس في المجموع.

ماذا ستتعلم في «عناصر Stateless مقابل Stateful»؟

افهم الفروقات الأساسية بين StatelessWidget وStatefulWidget، وتعلّم متى وكيف تستخدم كلًا منهما لبناء واجهات مستخدم ديناميكية تتمرن على Flutter Mobile Development مع أكواد عملية تشغلها مباشرة في المتصفح، ومدرس ذكاء اصطناعي متاح 24/7 يجيب على أسئلتك أثناء عملك.

هل أحتاج إلى خبرة سابقة لأبدأ Flutter Mobile Development؟

لا تُشترط خبرة سابقة. Flutter Mobile Development على CoddyKit منظم للمبتدئين حتى المتقدمين، لذا يمكنك البدء من هنا أو من البداية والتقدم بسرعتك الخاصة. هذا هو الدرس 1 من أصل 4.

كم من الوقت يستغرق درس «عناصر Stateless مقابل Stateful»؟

معظم دروس CoddyKit تستغرق حوالي 5–10 دقائق. كل منها موجز وتفاعلي، لذا تحرز تقدماً مستمراً وتستأنف من حيث توقفت عبر الويب والتطبيق.

هل يمكنني كتابة وتشغيل أكواد في درس Flutter Mobile Development هذا؟

نعم. كل درس في Flutter Mobile Development يتضمن محرر أكواد مدمج، لذا تكتب وتشغل أكواداً حقيقية مباشرة في متصفحك وتحصل على تعليقات فورية من الذكاء الاصطناعي — بدون إعداد محلي.

جميع الدروس في هذه الدورة

عناصر Stateless مقابل Stateful
عناصر التخطيط الأساسية
عناصر واجهة المستخدم التفاعلية
إنشاء قوائم قابلة للتمرير باستخدام ListView

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