一、下载Flutter SDK
1、从官网下载
https://docs.flutter.dev/development/tools/sdk/releases
解压后放到固定目录，不能删除
2、官网下载很慢的话可以使用终端命令下载：
git clone https://github.com/flutter/flutter.git -b stable --depth 1
二、环境变量配置
1、在bash_profile文件里增加环境变量
bash_profile文件目录：~/.bash_profile
增加以下配置：注意替换flutter文件路径
export FLUTTER_HOME=这里换成下载好的flutter文件路径
export PATH=$PATH:$FLUTTER_HOME/bin
export PATH=$PATH:$FLUTTER_HOME/bin/cache/dart-sdk/bin
export PUB_HOSTED_URL=https://pub.flutter-io.cn
export FLUTTER_STORAGE_BASE_URL=https://storage.flutter-io.cn
保存退出，刷新.bash_profile文件
source ~/.bash_profile
2、重启终端，运行
flutter doctor
正常情况会下载完成配置安装，但新系统由于默认加载zsh配置，提示-bash: flutter: command not found 或者 zsh: command not found: flutter
处理办法：在zprofile文件里增加以下配置
zprofile文件目录：~/.zprofile
注意替换flutter文件路径
export FLUTTER_HOME=这里换成下载好的flutter文件路径
export PATH=$PATH:$FLUTTER_HOME/bin
保存退出，刷新.zprofile文件
source ~/.zprofile
三、重启终端，运行 flutter doctor
1、Error: The Flutter directory is not a clone of the GitHub project.
The flutter tool requires Git in order to operate properly;
to install Flutter, see the instructions at:
https://flutter.dev/get-started
在下载的flutter文件目录下，执行git init就行了
重新运行 flutter doctor
2、Flutter:Failed to retrieve the Dart SDK
解决办法：
执行flutter doctor之前，先执行一下命令
export PUB_HOSTED_URL=https://pub.flutter-io.cn
export FLUTTER_STORAGE_BASE_URL=https://storage.flutter-io.cn
等待下载完成即可
3、运行flutter doctor报如下错误
按提示运行flutter doctor --android-licenses还是报错
找到本地的 Flutter SDK，依次点开 flutter / packages / flutter_tools / lib / src / android / android_studio.dart ，打开 android_studio.dart 文件后，滑动到最下面，删除掉下图所示代码处的字符串 jdk 。
创建jre和jdk文件夹，将jbr里面的Contents文件夹拷贝进去
三、Mac OS 下载安装Android studio
官网下载链接：https://developer.android.google.cn/studio
flutter、dart插件安装
