In Yii, widgets are reusable components used to encapsulate common UI elements or logic. Its core role is to improve development efficiency and maintain interface consistency. Using Yii widgets can avoid repeated writing of code, realize code reuse, maintain unified interface, separate focus points, and facilitate expansion. Yii provides a variety of built-in widgets, such as ActiveForm for model forms, ListView/GridView display lists and table data, Pagination implementation of pagination control, and Menu dynamically generate navigation menus. When view code is found to be duplicated, logical and presentation required, or abstract dynamic behavior, custom widgets should be created. The method is to inherit yii\base.Widget and implement the run() method, and then call it through the widget() method and pass in the configuration options.

Yii widgets are reusable components that help you build user interfaces more efficiently in Yii applications. Their main purpose is to encapsulate commonly used UI elements or logic, so you don't have to write the same code over and over.

What Exactly Are Widgets in Yii?

Widgets in Yii are PHP classes that generate HTML or JavaScript-based interface elements. Think of them as building blocks for your front-end — things like form inputs, navigation menus, date pickers, or even something like a comment section. Each widget is self-contained, meaning it handles its own rendering and behavior.

For example, instead of manually writing out a dropdown menu with PHP loops and conditions every time, you can use Dropdown widget provided by Yii or create your own custom version.

Why Use Widgets?

Using widgets has several practical benefits:

• Code Reuse : Once you create a widget, you can use it across multiple pages or projects.
• Consistency : Ensures uniform look and behavior across your app.
• Separation of Concerns : Keeps your views cleaner by moving complex logic into widget classes.
• Extensibility : You can extend existing widgets to customize their behavior without rewriting everything.

If you're working on a large project with repetitive UI patterns, widgets become especially useful.

How Do You Use Built-in Widgets?

Yii comes with a set of built-in widgets that cover common use cases. Here's how you typically use them:

 <?= \yii\widgets\Menu::widget([
    &#39;items&#39; => [
        [&#39;label&#39; => &#39;Home&#39;, &#39;url&#39; => [&#39;/site/index&#39;]],
        [&#39;label&#39; => &#39;About&#39;, &#39;url&#39; => [&#39;/site/about&#39;]],
    ],
]) ?>

Some commonly used ones include:

• ActiveForm : For creating model-based forms.
• ListView / GridView : For displaying lists or tabular data.
• Pagination : Handles pagination controls.
• Menu : Builds navigation menus dynamically.

You usually pass an array of configuration options to define how the widget should behave or render.

When Should You Create Custom Widgets?

You might want to build a custom widget if:

• You find yourself repeating the same block of view code.
• You need a component that combines both logic and presentation.
• You want to abstract some dynamic behavior (like AJAX loading) into a reusable part.

Creating a custom widget involves defining a class that extends yii\base\Widget , and implementing the run() method. Then you call it like any other widget:

 <?= MyCustomWidget::widget([&#39;option1&#39; => $value]) ?>

It's not hard, but it does require organizing your code properly and sometimes thinking ahead about flexibility and configuration.

Basically that's it.

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