安装flutter
//打开环境变量配置
open ~/.bash_profile
//加入下面环境变量
export PUB_HOSTED_URL=https://pub.flutter-io.cn
export FLUTTER_STORAGE_BASE_URL=[https://storage.flutter-io.cn](https://storage.flutter-io.cn)
//生效
source ~/.bash_profile
//下载flutter
git clone -b beta [https://github.com/flutter/flutter.git](https://github.com/flutter/flutter.git)
//打开环境变量配置
open ~/.bash_profile
//加一行 xxx 安装目录
export PATH=/xxx/flutter/bin:$PATH
//生效
source ~/.bash_profile
//配置
flutter doctor
