ios-flutter混编时按以前的操作流程仔仔细细走了一边，但是到最后pod却发现始终导入不了flutter.framework。报错如下：
。。。。。。。。line 2: /packages/flutter_tools/bin/xcode_backend.sh: No such file or directory
。。。。。。。。line 3: /packages/flutter_tools/bin/xcode_backend.sh: No such file or directory
Command PhaseScriptExecution failed with a nonzero exit code
本来以为自己的flutter环境配置有问题 但是flutter doctor命令执行没问题。后来发现是Podfile官方的配置改了，改成如下：
platform :ios, '10.0'
use_frameworks!
target 'FlutterLeaning' do
flutter_application_path = '../my_flutter_module'
load File.join(flutter_application_path, '.ios', 'Flutter', 'podhelper.rb')
install_all_flutter_pods(flutter_application_path)
end
保存 ，cd到项目文件夹，pod install 。完美解决。
注意：pod之后要把以前添加的targets->build phases->Run script删除掉！！！！！！！！
