Flutter Single Instance

A simple way to check if your application is already running.

✅ - Confirmed working.
⚠️ - Always reports as first instance.

Installation

Add flutter_single_instance as a dependency in your pubspec.yaml file.

flutter pub add flutter_single_instance

MacOS

Disable sandboxing and enable networking in macos/Runner/DebugProfile.entitlements and macos/Runner/Release.entitlements files.

<key>com.apple.security.app-sandbox</key>
<false/>

<key>com.apple.security.network.server</key>
<true/>

<key>com.apple.security.network.client</key>
<true/>

• com.apple.security.app-sandbox: Set to false to allow access to the filesystem.
• com.apple.security.network.server: Set to true to allow the app to act as a server and listen for incoming focus requests.
• com.apple.security.network.client: Set to true to allow the app to act as a client and send focus requests to the server (i.e. the main instance).

Usage

A simple usage example:

import 'dart:io';

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

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  await windowManager.ensureInitialized();

  if (await FlutterSingleInstance().isFirstInstance()) {
    runApp(const MyApp());
  } else {
    print("App is already running");

    final err = await FlutterSingleInstance().focus();

    if (err != null) {
      print("Error focusing running instance: $err");
    }

    exit(0);
  }
}

Web and other unsupported platforms

You can safely use this package in web and other unsupported platforms. It will always return true for isFirstInstance method.

Limitations

• Currently this package does not provide a way to bring the existing instance to the front. If you have any ideas on how to achieve this, please open an issue or a pull request. This limitation has been resolved in version 1.2.0.