Lottie Animation Is Not Working In Windows

Apr 22, 2025 by ADMIN 43 views

**Lottie Animation Not Working in Windows: A Comprehensive Guide**

Introduction

Lottie animations are a popular way to add interactive and engaging visuals to web and mobile applications. However, users have reported issues with Lottie animations not working in Windows environments. In this article, we will delve into the problem, explore possible causes, and provide a step-by-step guide to troubleshoot and resolve the issue.

Problem with Lottie Animation

Users have reported encountering an "Unknown control: lottie" error when trying to use the Lottie control in their Flet applications, even though the flet-lottie package is installed in their environment. This error occurs on Windows operating systems, and users have tried various approaches to resolve the issue.

Environment

Flet Version: >=0.27.6
flet-lottie Version: 0.1.0
Operating System: Windows
Python Version: 3.13.3

Code Sample

ft.Lottie(
    src="assets/earth.json",  # Use the path directly
    animate=True,
    repeat=True,
    width=200,
    height=200,
)

Troubleshooting Steps

Verify flet-lottie installation: Confirm that flet-lottie is installed in the correct Python environment using pip list or uv pip list.
Reinstall dependencies: Try reinstalling dependencies using pip install -r requirements.txt --force-reinstall or uv sync --reinstall.
Verify Python interpreter: Verify that the Python interpreter used by the IDE/terminal matches the environment where packages are installed.
Restart IDE: Restart the IDE to ensure that any cached data is cleared.
Try loading Lottie file using both src and src_base64: Attempt to load the Lottie file using both relative path (src) and base64-encoded path (src_base64).

Additional Troubleshooting Steps

Check Lottie JSON file: Ensure that the Lottie JSON file exists at the specified path and is valid.
Verify Lottie control: Verify that the Lottie control is properly imported and configured in the Flet application.
Check for conflicts with other packages: Check if there are any conflicts with other packages that may be causing the issue.

Conclusion

The "Unknown control: lottie" error in Windows environments can be frustrating, but by following the troubleshooting steps outlined in this article, users can resolve the issue and get their Lottie animations working smoothly. Remember to verify flet-lottie installation, reinstall dependencies, verify Python interpreter, restart IDE, and try loading Lottie file using both src and src_base64.

Additional Resources

Flet documentation: https://flet.dev/docs/
flet-lottie documentation: https://github.com/flet-dev/flet-lottie
Lottie documentation: https://lottiefiles.com/docs/

Code Snippets

Code Snippet 1: Using src attribute

ft.Lottie(
    src="assets/earth.json",  # Use the path directly
    animate=True,
    repeat=True,
    width=200,
    height=200,
)

Code Sn 2: Using src_base64 attribute

import flet as ft
from flet_lottie import Lottie
import base64
import os

# Assume assets/satellite-earth-orbiting.json exists and is valid
LOTTIE_JSON_PATH = "assets/satellite-earth-orbiting.json"

def main(page: ft.Page):
    page.title = "Lottie Test"
    page.vertical_alignment = ft.MainAxisAlignment.CENTER

    json_base64 = None
    try:
        # Adjust path finding if necessary for the minimal example
        script_dir = os.path.dirname(os.path.abspath(__file__))
        absolute_path = os.path.normpath(os.path.join(script_dir, LOTTIE_JSON_PATH))
        with open(absolute_path, "r", encoding="utf-8") as f:
            json_data = f.read()
            json_base64 = base64.b64encode(json_data.encode('utf-8')).decode('utf-8')
    except Exception as e:
        print(f"Error loading Lottie JSON: {e}")
        # Add a text control showing the error if loading fails
        page.add(ft.Text(f"Error loading Lottie JSON: {e}"))
        return # Stop if loading failed

    if json_base64:
        lottie_control = Lottie(
            src_base64=json_base64,
            animate=True,
            repeat=True,
            width=200,
            height=200,
        )
        page.add(lottie_control)
    else:
         page.add(ft.Text("Lottie JSON could not be loaded."))


    page.update()

if __name__ == "__main__":
    ft.app(target=main, assets_dir="assets")

Code Snippet 3: Using both src and src_base64 attributes

ft.Lottie(
    src="assets/earth.json",  # Use the path directly
    animate=True,
    repeat=True,
    width=200,
    height=200,
)

import flet as ft
from flet_lottie import Lottie
import base64
import os

# Assume assets/satellite-earth-orbiting.json exists and is valid
LOTTIE_JSON_PATH = "assets/satellite-earth-orbiting.json"

def main(page: ft.Page):
    page.title = "Lottie Test"
    page.vertical_alignment = ft.MainAxisAlignment.CENTER

    json_base64 = None
    try:
        # Adjust path finding if necessary for the minimal example
        script_dir = os.path.dirname(os.path.abspath(__file__))
        absolute_path = os.path.normpath(os.path.join(script_dir, LOTTIE_JSON_PATH))
        with open(absolute_path, "r", encoding="utf-8") as f:
            json_data = f.read()
            json_base64 = base64.b64encode(json_data.encode('utf-8')).decode('utf-8')
    except Exception as e:
        print(f"Error loading Lottie JSON: {e}")
        # Add a text control showing the error if loading fails
        page.add(ft.Text(f"Error loading Lottie JSON: {e}"))
        return # Stop if loading failed

    if json_base64:
        lottie_control = Lottie(
            src_base64=json_base64,
            animate=True,
            repeat=True,
            width=200,
            height=200,
        )
        page.add(lottie_control)
   :
         page.add(ft.Text("Lottie JSON could not be loaded."))


    page.update()

if __name__ == "__main__":
    ft.app(target=main, assets_dir="assets")
```<br/>
**Lottie Animation Not Working in Windows: A Q&A Guide**
=====================================================

**Q: What is Lottie animation?**
-----------------------------

A: Lottie animation is a popular way to add interactive and engaging visuals to web and mobile applications. It uses a JSON file to define the animation, which can be loaded and played in various platforms.

**Q: What is the issue with Lottie animation in Windows?**
---------------------------------------------------

A: Users have reported encountering an "Unknown control: lottie" error when trying to use the Lottie control in their Flet applications, even though the flet-lottie package is installed in their environment.

**Q: What are the possible causes of the issue?**
------------------------------------------------

A: The possible causes of the issue include:

*   **Incorrect installation of flet-lottie**: Make sure that flet-lottie is installed in the correct Python environment.
*   **Conflicts with other packages**: Check if there are any conflicts with other packages that may be causing the issue.
*   **Invalid Lottie JSON file**: Ensure that the Lottie JSON file exists at the specified path and is valid.
*   **Incorrect configuration of Lottie control**: Verify that the Lottie control is properly imported and configured in the Flet application.

**Q: How can I troubleshoot the issue?**
-----------------------------------------

A: To troubleshoot the issue, follow these steps:

1.  **Verify flet-lottie installation**: Confirm that flet-lottie is installed in the correct Python environment using pip list or uv pip list.
2.  **Reinstall dependencies**: Try reinstalling dependencies using pip install -r requirements.txt --force-reinstall or uv sync --reinstall.
3.  **Verify Python interpreter**: Verify that the Python interpreter used by the IDE/terminal matches the environment where packages are installed.
4.  **Restart IDE**: Restart the IDE to ensure that any cached data is cleared.
5.  **Try loading Lottie file using both src and src_base64**: Attempt to load the Lottie file using both relative path (src) and base64-encoded path (src_base64).

**Q: What are the additional troubleshooting steps I can take?**
--------------------------------------------------------------

A: Additional troubleshooting steps include:

1.  **Check Lottie JSON file**: Ensure that the Lottie JSON file exists at the specified path and is valid.
2.  **Verify Lottie control**: Verify that the Lottie control is properly imported and configured in the Flet application.
3.  **Check for conflicts with other packages**: Check if there are any conflicts with other packages that may be causing the issue.

**Q: How can I resolve the issue?**
-----------------------------------

A: To resolve the issue, follow these steps:

1.  **Verify flet-lottie installation**: Confirm that flet-lottie is installed in the correct Python environment using pip list or uv pip list.
2.  **Reinstall dependencies**: Try reinstalling dependencies using pip install -r requirements.txt --force-reinstall or uv sync --reinstall.
3.  **Verify Python interpreter**: Verify that the Python interpreter used by the IDE/terminal matches the environment where packages are installed.
4.  **Restart IDE**: Restart the IDE to ensure that any cached data is cleared.
5.  **Try loading Lottie file using both src and src_base64**: Attempt to load the Lottie file using both relative path (src) and base64-encoded path (src_base64).

**Q: What are the best practices for using Lottie animation in Flet applications?**
--------------------------------------------------------------------------------

A: The best practices for using Lottie animation in Flet applications include:

1.  **Verify flet-lottie installation**: Confirm that flet-lottie is installed in the correct Python environment using pip list or uv pip list.
2.  **Use correct configuration of Lottie control**: Verify that the Lottie control is properly imported and configured in the Flet application.
3.  **Check for conflicts with other packages**: Check if there are any conflicts with other packages that may be causing the issue.
4.  **Use both src and src_base64 attributes**: Attempt to load the Lottie file using both relative path (src) and base64-encoded path (src_base64).

**Q: Where can I find more information about Lottie animation and Flet applications?**
-----------------------------------------------------------------------------------

A: You can find more information about Lottie animation and Flet applications on the following resources:

*   **Flet documentation**: <https://flet.dev/docs/>
*   **flet-lottie documentation**: <https://github.com/flet-dev/flet-lottie>
*   **Lottie documentation**: <https://lottiefiles.com/docs/>