1. 解压flutter_macos_1.22.6-stable.zip文件
    2. 修改~/.bash_profile的export PATH=~/code/SDK/flutter_1.22.6-3/bin:${PATH}
    3. 执行source ~/.bash_profile
    4. 执行dart —version 会下载dart-sdk
    5. 执行flutter doctor
    6. 项目内执行flutter pub get