3 1 Creating Custom Widgets Explained

Key Concepts

• Custom Widgets: User interface elements tailored to specific needs.
• Streamlit Components: Framework for integrating custom widgets into Streamlit apps.
• React.js: JavaScript library for building user interfaces.
• HTML/CSS/JavaScript: Technologies used to create custom widgets.
• Integration: Combining custom widgets with Streamlit for enhanced functionality.

Custom Widgets

Custom widgets are user interface elements tailored to specific needs. They allow developers to create interactive components that are not available in Streamlit's default widget library.

Streamlit Components

Streamlit Components is a framework that allows developers to integrate custom widgets into Streamlit apps. It provides a bridge between Streamlit and external JavaScript libraries, enabling the creation of complex and interactive user interfaces.

React.js

React.js is a JavaScript library for building user interfaces. It is commonly used to create custom widgets due to its component-based architecture and efficient rendering capabilities.

HTML/CSS/JavaScript

HTML, CSS, and JavaScript are the foundational technologies used to create custom widgets. HTML defines the structure, CSS styles the appearance, and JavaScript adds interactivity.

Integration

Integration involves combining custom widgets with Streamlit to enhance the app's functionality. This is achieved by embedding the custom widget code within a Streamlit component and passing data between Streamlit and the widget.

Examples

Example 1: Simple Custom Widget

import streamlit as st
import streamlit.components.v1 as components

def custom_widget():
    return "Hello from custom widget!"

components.html("""
<div>
    <h1>Custom Widget</h1>
    <p>{custom_widget()}</p>
</div>
""")
    

Example 2: React.js Custom Widget

import streamlit as st
import streamlit.components.v1 as components

components.html("""
<div id="root"></div>
<script src="https://unpkg.com/react@17/umd/react.development.js" crossorigin></script>
<script src="https://unpkg.com/react-dom@17/umd/react-dom.development.js" crossorigin></script>
<script>
    const App = () => <h1>Hello from React!</h1>;
    ReactDOM.render(<App />, document.getElementById('root'));
</script>
""")
    

Analogies

Think of custom widgets as specialized tools in a toolbox. Streamlit Components are like the mechanism that allows you to use these tools in your Streamlit app. React.js is like the blueprint for creating these tools, while HTML/CSS/JavaScript are the materials used to build them. Integration is like assembling the tools into a functional machine.

By mastering the creation of custom widgets, you can extend the capabilities of your Streamlit apps and create highly interactive and tailored user interfaces.