Flutter – How to Turn on Camera Flash

Flutter is a UI toolkit developed and maintained by Google. It was released in May 2017 to the public. It is now one of the most popular cross-platform development frameworks among beginners and experienced application developers. It has a straightforward learning curve and uses the Dart programming language for developing the applications.

Every smartphone generally has a flashlight on the backside of the phone. In this article, we will learn how that flashlight can be controlled in Flutter.

Approach

To control the flashlight in a Flutter app, we will use the camera package, this package will allow us to access the device’s camera functionalities including the flashlight.

Syntax

await _controller.setFlashMode(FlashMode.torch);

Example Project

The below example project shows how to use the flashlight using the camera package.

Note: Before running this code make sure that you have installed the camera package in your Flutter project. You can do so by running the below command from your project root:

 flutter pub add camera

Dart

import 'package:flutter/material.dart';
import 'package:camera/camera.dart';

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

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

    @override
    _FlashlightAppState createState() => _FlashlightAppState();
}

class _FlashlightAppState extends State<FlashlightApp> {
    late List<CameraDescription> cameras;
    late CameraController _controller;
    Color _bgColor = Colors.white;

    @override
    void initState() {
        initializeCamera();
        super.initState();
    }

    Future<void> initializeCamera() async {
        cameras = await availableCameras();
        _controller = CameraController(cameras[0], ResolutionPreset.low);
        await _controller.initialize();
    }

    Future<void> toggleFlashlight() async {
        if (_controller.value.isInitialized) {
            if (_controller.value.flashMode == FlashMode.off) {
                await _controller.setFlashMode(FlashMode.torch);
                setState(() {
                    _bgColor = Colors.greenAccent;
                });
            } else {
                await _controller.setFlashMode(FlashMode.off);
                setState(() {
                    _bgColor = Colors.white;
                });
            }
        }
    }

    @override
    void dispose() {
        _controller.dispose();
        super.dispose();
    }

    @override
    Widget build(BuildContext context) {
        return MaterialApp(
            title: "GFG- Flutter Flashlight App",
            home: Scaffold(
                backgroundColor: _bgColor,
                appBar: AppBar(
                    title: const Text('Flutter Flashlight App'),
                ),
                body: Center(
                    child: IconButton(
                        icon: const Icon(Icons.flash_on),
                        onPressed: toggleFlashlight,
                    ),
                ),
            ),
        );
    }
}

Output:

Since the back of the phone cannot be recorded on the screen. The background color of the screen is changed to green when the flashlight is on.