3 Custom Components Explained

Key Concepts

• Custom Components: Extending Streamlit's functionality with custom widgets.
• Component Lifecycle: Understanding the lifecycle of a custom component.
• State Management: Managing state within custom components.
• Event Handling: Handling events triggered by custom components.
• Integration: Integrating custom components into Streamlit apps.

Custom Components

Custom components allow you to extend Streamlit's functionality by creating your own widgets. These components can be integrated into your Streamlit app to provide additional features.

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

def custom_component():
    return "Hello from custom component!"

components.html("""
<div>
    <h1>Custom Component</h1>
    <p>{custom_component()}</p>
</div>
""")
    

Component Lifecycle

Understanding the lifecycle of a custom component involves knowing when the component is created, updated, and destroyed. This helps in managing resources and state effectively.

import streamlit as st

if 'count' not in st.session_state:
    st.session_state.count = 0

def increment_counter():
    st.session_state.count += 1

st.button('Increment', on_click=increment_counter)
st.write('Count:', st.session_state.count)
    

State Management

State management within custom components involves maintaining the state of the component across multiple interactions. This can be achieved using session state in Streamlit.

import streamlit as st

if 'count' not in st.session_state:
    st.session_state.count = 0

def increment_counter():
    st.session_state.count += 1

st.button('Increment', on_click=increment_counter)
st.write('Count:', st.session_state.count)
    

Event Handling

Event handling in custom components involves responding to user interactions such as clicks, inputs, and other actions. This allows for dynamic and interactive components.

import streamlit as st

def handle_click():
    st.write("Button clicked!")

st.button('Click me', on_click=handle_click)
    

Integration

Integrating custom components into Streamlit apps involves importing and using the custom component within your Streamlit script. This allows you to extend the functionality of your app.

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

def custom_component():
    return "Hello from custom component!"

components.html("""
<div>
    <h1>Custom Component</h1>
    <p>{custom_component()}</p>
</div>
""")
    

Analogies

Think of custom components as adding special features to your car. The component lifecycle is like understanding the stages your car goes through from manufacturing to disposal. State management is like keeping track of your car's mileage. Event handling is like responding to your car's dashboard alerts. Integration is like installing a new navigation system in your car.

By mastering custom components, you can create powerful, interactive, and feature-rich Streamlit applications.