1. 环境
   react-native 0.7.0
2. 安装
   npm i -S react-native-config
3. 设置.env文件

// .env.staging
API_URL = https://dev.xxxx.com

4. 配置package.json

 "scripts": {
    "android:staging": "ENVFILE=.env.staging react-native run-android",
  },

5. 安卓配置
   android/app/build.gradle 文件最末尾

apply from: project(':react-native-config').projectDir.getPath() + "/dotenv.gradle" 

6. 打包时指定环境
   $ cd android && ENVFILE=.env.staging ./gradlew assembleRelease
7. 解决 Failed to transform react-native-0.71.0-rc.0-release.aar
android/app/build.gradle

buildscript {
    // ...
}


allprojects {
    repositories {
       exclusiveContent {
           filter {
               includeGroup "com.facebook.react"
           }
           forRepository {
               maven {
                   url "$rootDir/../node_modules/react-native/android"
               }
           }
       }
        // ...
    }
}

参考来源 https://github.com/facebook/react-native/issues/35204

9. iOS配置
   未配置