從年初開始在項(xiàng)目中引入flutter，用其實(shí)現(xiàn)了部分簡(jiǎn)單的頁面。
我們團(tuán)隊(duì)中Pod的使用和主流有些不一樣，Pods目錄是不寫入.gitignore的??阅签。

原因：

當(dāng)通過pod引入Flutter module并執(zhí)行pod install 后，Pod Project中Flutter相關(guān)的Targrt配置里都會(huì)寫入Flutter.xcframework的絕對(duì)路徑蝎抽；
再加上我們git沒有忽略pod目錄政钟；
所以如果不同的電腦Flutter安裝路徑不同，就會(huì)編譯報(bào)錯(cuò)樟结，找不到Flutter.xcframework养交。

有比較簡(jiǎn)單的解決方案

1. Pods文件夾不要上傳到git
   或
2. 確保各電腦的flutter安裝路徑統(tǒng)一，比如都是Users/flutter/狭吼，

由于我想了解下flutter的構(gòu)建方式层坠，因此決定通過編寫腳本的方式解決這個(gè)問題

通過分析，看到路徑的配置是在xxxxxx/flutter/packages/flutter_tools/bin/podhelper.rb這個(gè)腳本中(省略了無關(guān)的代碼)

def flutter_additional_ios_build_settings(target)
    ...
  artifacts_dir = File.join('..', '..', '..', '..', 'bin', 'cache', 'artifacts', 'engine')
  debug_framework_dir = File.expand_path(File.join(artifacts_dir, 'ios', 'Flutter.xcframework'), __FILE__)
  release_framework_dir = File.expand_path(File.join(artifacts_dir, 'ios-release', 'Flutter.xcframework'), __FILE__)
  ...
  target.build_configurations.each do |build_configuration|
        ...
    # Skip other updates if it's not a Flutter plugin (transitive dependency).
    next unless target.dependencies.any? { |dependency| dependency.name == 'Flutter' }
    ...
    # Profile can't be derived from the CocoaPods build configuration. Use release framework (for linking only).
    configuration_engine_dir = build_configuration.type == :debug ? debug_framework_dir : release_framework_dir
    Dir.new(configuration_engine_dir).each_child do |xcframework_file|
      next if xcframework_file.start_with?('.') # Hidden file, possibly on external disk.
      if xcframework_file.end_with?('-simulator') # ios-arm64_x86_64-simulator
        build_configuration.build_settings['FRAMEWORK_SEARCH_PATHS[sdk=iphonesimulator*]'] = "\"#{configuration_engine_dir}/#{xcframework_file}\" $(inherited)"
      elsif xcframework_file.start_with?('ios-') # ios-arm64
        build_configuration.build_settings['FRAMEWORK_SEARCH_PATHS[sdk=iphoneos*]'] = "\"#{configuration_engine_dir}/#{xcframework_file}\" $(inherited)"
       # else Info.plist or another platform.
      end
    end
   ...
  end
end

如果能夠修改這里腳本寫入的路徑刁笙，比如debug_framework_dir = File.join("$(Flutter_Install_Path)", 'bin', 'cache', 'artifacts', 'engine', 'ios', 'Flutter.xcframework')破花，然后只需要在xcconfig中定義不同的Flutter_Install_Path就可以解決問題了。

但是修改flutter中的腳本是比較危險(xiǎn)的操作疲吸，因此決定通過編寫腳本再次修改掉flutter寫入的Flutter.xcframework路徑座每。
方案還是比較簡(jiǎn)單的，下面直接給出步驟：

1. 在Podfile同級(jí)目錄創(chuàng)建一個(gè)文件Flutter_Path.xcconfig摘悴，寫入自己電腦上Flutter安裝路徑kv （這個(gè)文件需要寫入.gitignore)

   Flutter_Install_Path = /Users/dadadongl/flutter
   

2. 修改Podfile中的腳本 （下面是修改前/后）

   # 修改前
   post_install do |installer|  
     flutter_post_install(installer) if defined?(flutter_post_install)
   end
   

    # 修改后
    post_install do |installer|
      # 先執(zhí)行flutter正常的腳本
      flutter_post_install(installer) if defined?(flutter_post_install)
    
      # 注入環(huán)境變量 & 修改flutter默認(rèn)寫入的framework search path
   
      # 遍歷Pod中的Targets
      installer.pods_project.targets.each do |target|
    
        # 修改flutter.xcframework的引用路徑配置 （后面這段腳本基本是基于flutter的腳本修改的峭梳，做到改動(dòng)最少）
        # 跳過沒有依賴'Flutter'的target
        next unless target.dependencies.any? { |dependency| dependency.name == 'Flutter' }
   
        # 構(gòu)造使用了環(huán)境變量$(Flutter_Install_Path)"的search path
        debug_framework_dir = File.join("$(Flutter_Install_Path)", 'bin', 'cache', 'artifacts', 'engine', 'ios', 'Flutter.xcframework')
        release_framework_dir = File.join("$(Flutter_Install_Path)", 'bin', 'cache', 'artifacts', 'engine', 'ios-release', 'Flutter.xcframework')
        # 解析自定義的xcconfig文件，為了拿到Flutter安裝路徑
        xcconfig = Xcodeproj::Config.new("./Flutter_Path.xcconfig")
        flutter_DIR = xcconfig.attributes["Flutter_Install_Path"]
        
        # 拿到Flutter的安裝絕對(duì)路徑
        full_debug_framework_dir = File.join(flutter_DIR, 'bin', 'cache', 'artifacts', 'engine', 'ios', 'Flutter.xcframework')
        full_release_framework_dir = File.join(flutter_DIR, 'bin', 'cache', 'artifacts', 'engine', 'ios-release', 'Flutter.xcframework')
        
        # 遍歷Target下的配置環(huán)境（Debug 蹂喻、Release）
        target.build_configurations.each do |build_configuration|
          
          # 追加自定義環(huán)境變量到 Pod 庫的 .xcconfig 文件葱椭，為了編譯時(shí)能夠識(shí)別$(Flutter_Install_Path)
          xcconfig_path = build_configuration.base_configuration_reference.real_path
          # 這里導(dǎo)入時(shí)相對(duì)pod.debug.xcconfig的路徑
          File.write(xcconfig_path, "#include \"../../../Flutter_Path.xcconfig\"", mode: 'a')
          
          # 修改 FRAMEWORK_SEARCH_PATHS
          configuration_engine_dir = build_configuration.type == :debug ? debug_framework_dir : release_framework_dir
          full_configuration_engine_dir = build_configuration.type == :debug ? full_debug_framework_dir : full_release_framework_dir
         
          Dir.new(full_configuration_engine_dir).each_child do |xcframework_file|
            next if xcframework_file.start_with?('.') # Hidden file, possibly on external disk.
            
            if xcframework_file.end_with?('-simulator') # ios-arm64_x86_64-simulator
              build_configuration.build_settings['FRAMEWORK_SEARCH_PATHS[sdk=iphonesimulator*]'] = "\"#{configuration_engine_dir}/#{xcframework_file}\" $(inherited)"
            elsif xcframework_file.start_with?('ios-') # ios-arm64
              build_configuration.build_settings['FRAMEWORK_SEARCH_PATHS[sdk=iphoneos*]'] = "\"#{configuration_engine_dir}/#{xcframework_file}\" $(inherited)"
              # else Info.plist or another platform.
            end
          end 
        end
      end
    end
   

3. 重新執(zhí)行Pod install

通過上述步驟后，就會(huì)把Flutter_Install_Path = /Users/dadadongl/flutter注入各Pod Target口四，然后修改后的framework search path就可以找到正確的路徑孵运，并成功編譯。