使用Flutter打包IOS，都会有三方依赖。IOS的依赖是用CocoaPods来管理的。使用Flutter doctor会提示安装CocoaPods.
根据提示安装CocoaPods，直接安装就卡在这里一直不动了。
$sudo gem install cocoapods
在网上找到个参数，可以查看安装进度，在最后加上-V。
# 注意V是大写 $sudo gem install cocoapods -V
看到安装过程，发现是网的问题，因为gem的源地址在国外
解决gem安装慢或卡住
- 使用梯子直接安装。
- 将gem的源改为国内镜像。
替换源是最简单的方法
# 替换源 $ gem sources --add https://gems.ruby-china.com/ --remove https://rubygems.org/ # 查看替换后的源地址 $ gem sources -l https://gems.ruby-china.com # 确保只有 gems.ruby-china.com
解决Failed to build gem native extension
替换gem源之后安装到最后又碰到以下问题。
Building native extensions. This could take a while... current directory: /Library/Ruby/Gems/2.3.0/gems/ffi-1.14.2/ext/ffi_c /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/bin/ruby -r ./siteconf20210203-987-tfjdrx.rb extconf.rb mkmf.rb can't find header files for ruby at /System/Library/Frameworks/Ruby.framework/Versions/2.3/usr/lib/ruby/include/ruby.h ERROR: Error installing cocoapods: ERROR: Failed to build gem native extension. Building has failed. See above output for more information on the failure. extconf failed, exit code 1 Gem files will remain installed in /Library/Ruby/Gems/2.3.0/gems/ffi-1.14.2 for inspection. Results logged to /Library/Ruby/Gems/2.3.0/extensions/universal-darwin-18/2.3.0/ffi-1.14.2/gem_make.out
Google搜索发现是MacOS缺少一些头文件。因为我的是10.14。所以直接使用以下命令安装工具包。
$ open /Library/Developer/CommandLineTools/Packages/macOS_SDK_headers_for_macOS_10.14.pkg
如果不想用命令也可以直接进入这个目录，双击安装，都会弹出安装界面。
安装后，重新使用sudo gem install cocoapods就能安装成功了。
最后运行Flutter doctor,IOS显示正常。
$ flutter doctor Doctor summary (to see all details, run flutter doctor -v): [✓] Flutter (Channel stable, 1.22.6, on Mac OS X 10.14.6 18G7016 darwin-x64, locale zh-Hans-CN) [✓] Android toolchain - develop for Android devices (Android SDK version 30.0.3) [✓] Xcode - develop for iOS and macOS (Xcode 11.3.1) [✓] Android Studio (version 4.0) [!] Connected device ! No devices available ! Doctor found issues in 1 category.
