已有项目集成flutter，集成方式是Option A - Embed with CocoaPods and the Flutter SDK
按照官网的步骤到打开xcode编译却报错，'Flutter/Flutter.h' file not found！！！！！
还有人说iOS工程命名不规范，我重新建工程结果还是 Flutter/Flutter.h' file not found！
看完这个发现我没有官方说的这个错误，执行 flutter doctor，有一个告警，提示cocopod版本低于1.10.0，我的版本为1.8.4。
[!] The version of CocoaPods used to generate the lockfile (1.10.1) is higher than the version of the current executable (1.8.4). Incompatibility issues may arise.
只能升级cocopod，网上找到的升级命令如下：
sudo gem install cocoapods
我的ruby版本是2.6.0提示文件找不到，具体的错误如下。
Password:
Building native extensions. This could take a while...
ERROR: Error installing cocoapods:
ERROR: Failed to build gem native extension.
current directory: /Library/Ruby/Gems/2.6.0/gems/ffi-1.15.1/ext/ffi_c
/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/bin/ruby -I /Library/Ruby/Site/2.6.0 -r ./siteconf20210612-9541-peq40b.rb extconf.rb
checking for ffi.h... *** extconf.rb failed ***
Could not create Makefile due to some reason, probably lack of necessary
libraries and/or headers. Check the mkmf.log file for more details. You may
need configuration options.
Provided configuration options:
--with-opt-dir
--without-opt-dir
--with-opt-include
--without-opt-include=${opt-dir}/include
--with-opt-lib
--without-opt-lib=${opt-dir}/lib
--with-make-prog
--without-make-prog
--srcdir=.
--curdir
--ruby=/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/bin/$(RUBY_BASE_NAME)
--with-ffi_c-dir
--without-ffi_c-dir
--with-ffi_c-include
--without-ffi_c-include=${ffi_c-dir}/include
--with-ffi_c-lib
--without-ffi_c-lib=${ffi_c-dir}/lib
--enable-system-libffi
--disable-system-libffi
--with-libffi-config
--without-libffi-config
--with-pkg-config
--without-pkg-config
/System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/mkmf.rb:467:in `try_do': The compiler failed to generate an executable file. (RuntimeError)
You have to install development tools first.
from /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/mkmf.rb:585:in `block in try_compile'
from /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/mkmf.rb:534:in `with_werror'
from /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/mkmf.rb:585:in `try_compile'
from /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/mkmf.rb:1109:in `block in have_header'
from /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/mkmf.rb:959:in `block in checking_for'
from /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/mkmf.rb:361:in `block (2 levels) in postpone'
from /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/mkmf.rb:331:in `open'
from /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/mkmf.rb:361:in `block in postpone'
from /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/mkmf.rb:331:in `open'
from /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/mkmf.rb:357:in `postpone'
from /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/mkmf.rb:958:in `checking_for'
from /System/Library/Frameworks/Ruby.framework/Versions/2.6/usr/lib/ruby/2.6.0/mkmf.rb:1108:in `have_header'
from extconf.rb:10:in `system_libffi_usable?'
from extconf.rb:42:in `<main>'
To see why this extension failed to compile, please check the mkmf.log which can be found here:
/Library/Ruby/Gems/2.6.0/extensions/universal-darwin-19/2.6.0/ffi-1.15.1/mkmf.log
extconf failed, exit code 1
Gem files will remain installed in /Library/Ruby/Gems/2.6.0/gems/ffi-1.15.1 for inspection.
Results logged to /Library/Ruby/Gems/2.6.0/extensions/universal-darwin-19/2.6.0/ffi-1.15.1/gem_make.out
网络上解决办法就是升级ruby，由于我不想安装rvm，我就去官网下载了一个最新的稳定版本3.0.1，按照官网的步骤编译安装（噩梦的开始），也安装成功了，ruby -v 显示是3.0.1。
于是我重复上面的步骤重新安装cocopod，又是遇到一个新错误：
ERROR: While executing gem ... (Gem::Exception)
OpenSSl is not available. Install OpenSSL and rebuild Ruby (preferred) or use non-HTTPS sources
于是我使用brew 更新openssl，发现brew又要更新，一顿操作把brew 安装的内容都更新了一遍，真是ma mai pi!!!!!
按网上资料，设置openssl的路径重新编译ruby3.0.1，再次安装，结果还是失败的。
然后又找如何删除ruby，找到源码文件夹执行 make uninstall 就可以了。
没办法只能寻找另一个方法，使用rvm安装，rvm安装前又要生成GPG keys，官网：https://rvm.io/
生成了KEY，下载RVM的时候提示被服务器拒绝访问。最后的解决办法是关闭WIFI。因为我的笔记本电脑连了有线（wifi经常掉线）。
最后我还是安装了RVM，重新安装ruby2.7.2，再次安装cocopods。
升级cocopods成功后，pod install完成，iOS和flutter混合工程总算是能编译成功了！
吐槽：我也不知道我是经历了什么，升级了一堆的软件，忙了一下午，心好累啊！！
千万记住不要轻易的去编译源码安装ruby!!!!!!
最后补一张图，坚持总有收获，加油！
