如何区分Flutter代码是由原生项目还是纯Flutter项目启动？

以下几种方案可以帮你区分Flutter代码是由iOS原生项目启动，还是由纯Flutter的main.dart直接启动，且不会污染全局SDK或其他项目：

方案一：原生侧传递启动标识（最准确） #

在iOS原生创建FlutterViewController时，通过初始化参数或MethodChannel向Flutter侧传递启动来源标识，Flutter侧读取该标识即可区分。

iOS原生代码示例 #

方式1：通过initialRoute传递

// 原生创建FlutterViewController时
FlutterViewController *flutterVC = [[FlutterViewController alloc] initWithProject:nil nibName:nil bundle:nil];
// 自定义路由作为启动标识，纯Flutter启动时默认是空字符串或"/"
flutterVC.initialRoute = @"native_launch";

方式2：通过MethodChannel传递

FlutterViewController *flutterVC = [[FlutterViewController alloc] initWithProject:nil nibName:nil bundle:nil];
FlutterMethodChannel *launchChannel = [FlutterMethodChannel methodChannelWithName:@"com.your.app/launch_source" binaryMessenger:flutterVC.binaryMessenger];
// 向Flutter发送启动来源
[launchChannel invokeMethod:@"setSource" arguments:@"native"];

Flutter侧代码示例 #

对应方式1：读取initialRoute

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  // 获取默认路由，纯Flutter启动时默认是"/"或空字符串
  final String initialRoute = WidgetsBinding.instance.window.defaultRouteName;
  final bool isNativeLaunch = initialRoute == "native_launch";
  runApp(MyApp(isNativeLaunch: isNativeLaunch));
}

对应方式2：通过MethodChannel接收

import 'package:flutter/services.dart';

void main() async {
  WidgetsFlutterBinding.ensureInitialized();
  bool isNativeLaunch = false;
  const MethodChannel _channel = MethodChannel("com.your.app/launch_source");
  
  try {
    // 尝试获取原生传递的标识，纯Flutter启动时会抛出异常
    final String? source = await _channel.invokeMethod("getSource");
    isNativeLaunch = source == "native";
  } on PlatformException {
    // 捕获异常说明是纯Flutter启动
    isNativeLaunch = false;
  }
  
  runApp(MyApp(isNativeLaunch: isNativeLaunch));
}

方案二：项目级环境变量配置（无需修改原生代码） #

在Android Studio的Flutter运行配置中，为纯Flutter启动设置项目专属环境变量，Flutter侧读取该变量即可区分，不会影响全局SDK或其他项目。

配置步骤 #

1. 打开Android Studio的Run > Edit Configurations
2. 选择你的Flutter运行配置，切换到Environment Variables标签
3. 添加变量：LAUNCH_SOURCE=flutter，点击保存

Flutter侧代码示例 #

import 'dart:io';

void main() {
  WidgetsFlutterBinding.ensureInitialized();
  // 纯Flutter启动时该变量存在，原生启动时不存在
  final bool isNativeLaunch = Platform.environment['LAUNCH_SOURCE'] != 'flutter';
  runApp(MyApp(isNativeLaunch: isNativeLaunch));
}

方案对比 #

内容的提问来源于stack exchange，提问作者ximmyxiao