官方文档
将 Flutter module 集成到 iOS 项目
https://flutter.cn/docs/development/add-to-app/ios/project-setup

• 1、flutter pub get
  ->Flutter.framework
• 2、pod install
  podhelper.rb->.ios下：Flutter.framework、 App.framework
• 3、xcodebuild
  xcode_backend.sh->Debug-iphoneos目录下：App.framework、
  .ios下Flutter.framework

1、flutter pub get

（1）生成.ios

（1）这时候还没有App.framework ， podspec文件是有了

（2）有engine，Flutter.framework。

（3）有插件列表 podspec FlutterPluginRegistrant.podspec，这时没有symlinks/plugins目录软链接

（4）导出当前的环境变量 flutter_export_environment.sh

（2）生成依赖列表

flutter-plugins-dependencies

image.png

2、pod install

执行 podHelper.rb 脚本

做2件事情：

（1）、 把这3个pod 引进native

    Flutter.framework               Flutter.podspec
    插件注册                        FlutterPluginRegistrant.podspec
   plugins下面的所有用到的插件
    App.framework                   flutter_commercial.podspec
       

• 安装Flutter.framework
  拷贝ios-release版本
  /Volumes/huc/opt/fvm/versions/2.2.0/bin/cache/artifacts/engine/ios-release

• 安装插件
  从flutter-plugins-dependencies列表，把依赖的插件从
  /opt/fvm/versions/2.2.0/.pub-cache
  拷贝一个快捷链接目录出来。
  然后pod依赖用本地path依赖。

  plugins_file = File.expand_path('.flutter-plugins-dependencies', flutter_application_path)
  plugin_pods = flutter_parse_dependencies_file_for_ios_plugin(plugins_file)
  plugin_pods.each do |plugin_hash|
    plugin_name = plugin_hash['name']
    plugin_path = plugin_hash['path']
    if (plugin_name && plugin_path)
      symlink = File.join(symlinks_dir, plugin_name)
      FileUtils.rm_f(symlink)
      File.symlink(plugin_path, symlink)
      pod plugin_name, :path => File.join(symlink, 'ios'), :inhibit_warnings => true
    end
  end

• 安装App.framework
  生成一个默认的App.framework 16Kb 一行代码用来占位置

（2）、把一段脚本写进xcode 工程配置.xcodeproj

/Volumes/huc/opt/fvm/versions/2.2.0/packages/flutter_tools/bin/xcode_backend.sh build

      flutter_export_environment_path = File.join('${SRCROOT}', relative, 'flutter_export_environment.sh');
  script_phase :name => 'Run Flutter Build flutter_commercial Script',
    :script => "set -e\nset -u\nsource \"#{flutter_export_environment_path}\"\nexport VERBOSE_SCRIPT_LOGGING=1 && \"$FLUTTER_ROOT\"/packages/flutter_tools/bin/xcode_backend.sh build",
    :execution_position => :before_compile
    end

多了.symlinks 和App.framework，重新拷贝了Flutter.xcframework

image.png

(3) pod install生成

Pods-HouseCommercialCube-frameworks.sh

  install_framework "${PODS_ROOT}/../../flutter_commercial/.ios/Flutter/App.framework"
  install_framework "${PODS_XCFRAMEWORKS_BUILD_DIR}/Flutter/Flutter.framework"

3、run app

执行 xcode_backend.sh

/Volumes/huc/opt/fvm/versions/2.2.0/packages/flutter_tools/bin/xcode_backend.sh 

做3件事情：

（1） 不太懂

AppFrameworkInfo.plist

  if FLTAssetsPath=$(/usr/libexec/PlistBuddy -c "Print :FLTAssetsPath" "${derived_dir}/AppFrameworkInfo.plist" 2>/dev/null); then
    if [[ -n "$FLTAssetsPath" ]]; then
      assets_path="${FLTAssetsPath}"
    fi

assets_path 这个后面也没有人用啊！

（2）通过环境 CONFIGURATION 重新 拿到对应 debug/release/profile版本的 engine： Flutter.framework

放到.ios下面

  local derived_dir="${SOURCE_ROOT}/Flutter"
  if [[ -e "${project_path}/.ios" ]]; then
    derived_dir="${project_path}/.ios/Flutter"
  fi



  local framework_path="${FLUTTER_ROOT}/bin/cache/artifacts/engine/${artifact_variant}"
  local flutter_engine_flag=""
  local local_engine_flag=""
  local flutter_framework="${framework_path}/Flutter.xcframework"



  # TODO(jmagman): use assemble copied engine in add-to-app.
  if [[ -e "${project_path}/.ios" ]]; then
    RunCommand rm -rf -- "${derived_dir}/engine/Flutter.framework"
    RunCommand cp -r -- "${flutter_framework}" "${derived_dir}/engine"
  fi

.ios/Flutter/engine/Flutter.xcframework
编译前， 把这个下面添加一个空文件， engine被覆盖了，那么那个空文件就没了？

对比了一下大小。 release
debug 版本的Flutter.xcframework 255M
ios-release 1.03 GB

一开始是1.03G， run之后， 变成了255M
说明确实拷贝到这里了

（2） 编译App.framework 放到 BUILT_PRODUCTS_DIR 下面

.ios下面App.framework 没有变

   RunCommand "${FLUTTER_ROOT}/bin/flutter"                                \
    ${verbose_flag}                                                       \
    ${flutter_engine_flag}                                                \
    ${local_engine_flag}                                                  \
    assemble                                                              \
    --no-version-check                                                    \
    --output="${BUILT_PRODUCTS_DIR}/"                                     \
    ${performance_measurement_option}                                     \
    -dTargetPlatform=ios                                                  \
    -dTargetFile="${target_path}"                                         \
    -dBuildMode=${build_mode}                                             \
    -dIosArchs="${ARCHS}"                                                 \
    -dSdkRoot="${SDKROOT}"                                                \
    -dSplitDebugInfo="${SPLIT_DEBUG_INFO}"                                \
    -dTreeShakeIcons="${TREE_SHAKE_ICONS}"                                \
    -dTrackWidgetCreation="${TRACK_WIDGET_CREATION}"                      \
    -dDartObfuscation="${DART_OBFUSCAT

App.framework 61Mb
Flutter.framework 35Mb

♦ rm 
-rf -- 
/Volumes/huc/houseCommercial/flutter_commercial/
.ios/Flutter/engine/Flutter.framework

♦ cp -r -- /opt/fvm/versions/2.2.0
/bin/cache/artifacts/engine/ios/Flutter.xcframework /Volumes/huc/houseCommercial/flutter_commercial/
.ios/Flutter/engine

♦ /opt/fvm/versions/2.2.0/bin/flutter
 --verbose assemble 
 --no-version-check 

 --output=/Users/huchu/Library/Developer/Xcode/DerivedData/HouseCommercialCube-haouxiieutwwizfrzseumgibdjxb/Build/Products/Debug-iphoneos/ 

 -dTargetPlatform=ios 

 -dTargetFile=lib/main.dart 
 
 -dBuildMode=debug 

 -dIosArchs=arm64 

 -dSdkRoot=/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS15.0.sdk 

 -dSplitDebugInfo= 

 -dTreeShakeIcons=false 

 -dTrackWidgetCreation=false 

 -dDartObfuscation=false 

 -dEnableBitcode= 

 -dCodesignIdentity=FD1A800911570C03E014A5628E4B5F87C416FC06 

 --ExtraGenSnapshotOptions= 

 --DartDefines= 

 --ExtraFrontEndOptions= 

 debug_ios_bundle_flutter_assets

（3）嵌入式库

"${PODS_ROOT}/Target Support Files/Pods-HouseCommercialCube/Pods-HouseCommercialCube-frameworks.sh"

if [[ "$CONFIGURATION" == "Debug" ]]; then
  ///其他动态库
  install_framework "${PODS_ROOT}/../../flutter_commercial/.ios/Flutter/App.framework"
  install_framework "${PODS_XCFRAMEWORKS_BUILD_DIR}/Flutter/Flutter.framework"
fi

if [[ "$CONFIGURATION" == "Release" ]]; then
  ///其他动态库
  install_framework "${PODS_ROOT}/../../flutter_commercial/.ios/Flutter/App.framework"
  install_framework "${PODS_XCFRAMEWORKS_BUILD_DIR}/Flutter/Flutter.framework"
fi

image.png