现状
Flutter官方的执行方案对Flutter工程及环境有很强的依赖性，非Flutter的成员在对iOS主工程进行迭代开发时需要依赖Flutter环境，团队合作十分不便。在通过Jenkins等打包时会有各种问题。
官方文章地址：Add Flutter to existing apps
基于Flutter版本1.9.1+hotfix 4
适用于以flutter module进行开发，作为iOS一个组件来引入的情况
（可以直接跳至方案查看结果）
期望
flutter 集成进iOS项目脱离Flutter环境及工程，Flutter工程开发与iOS原生开发互不影响。
分析
Flutter执行build之后产物介绍
在Flutter的module中执行flutter build ios --release后，我们的工程目录里有隐藏文件夹.ios，我们需要的Flutter产物基本都在其下的Flutter文件夹中。
image-20191031164025401.png
挨个分析一下内部我们需要的文件。
-
.symlinks
我们三方库的索引，内部每个文件夹下，都包含
ios文件夹，这个文件夹下都是一个pod库。 -
App.framework
Flutter项目的Dart代码编译而成的Framework。
-
engine
Flutter的引擎Framework，一个pod库。
-
FlutterPluginRegistrant
Flutter三方库的注册入口，一个pod库。
-
Generated.xcconfig
Flutter的路径信息，配置信息等。
-
podhelper.rb
pod执行的时候用到的脚本。后续会对这个文件做具体的分析
其他的文件基本都没什么用处可以不关注
官方方案分析
官方执行步骤：
- 在
Podfile中加入如下代码：
flutter_application_path = 'path/to/my_flutter/'
load File.join(flutter_application_path, '.ios', 'Flutter', 'podhelper.rb')
- 对每个Xcode target添加方法
install_all_flutter_pods(flutter_application_path)
target 'MyApp' do
install_all_flutter_pods(flutter_application_path)
end
target 'MyAppTests' do
install_all_flutter_pods(flutter_application_path)
end
分析：
第一步作用是设置flutter工程路径并添加脚本podhelper.rb。
第二步作用就是执行podhelper.rb中的方法install_all_flutter_pods，并将flutter工程路径变量传入。
那么下面我们来分析一下这个podhelper.rb中到底做了什么。
分析podhelper.rb
脚本代码如下：
# Install pods needed to embed Flutter application, Flutter engine, and plugins
# from the host application Podfile.
#
# @example
# target 'MyApp' do
# install_all_flutter_pods 'my_flutter'
# end
# @param [String] flutter_application_path Path of the root directory of the Flutter module.
# Optional, defaults to two levels up from the directory of this script.
# MyApp/my_flutter/.ios/Flutter/../..
def install_all_flutter_pods(flutter_application_path = nil)
flutter_application_path ||= File.join('..', '..')
install_flutter_engine_pod
# install_flutter_plugin_pods(flutter_application_path)
install_flutter_application_pod(flutter_application_path)
end
# Install Flutter engine pod.
#
# @example
# target 'MyApp' do
# install_flutter_engine_pod
# end
def install_flutter_engine_pod
engine_dir = File.join(__dir__, 'engine')
if !File.exist?(engine_dir)
# Copy the debug engine to have something to link against if the xcode backend script has not run yet.
# CocoaPods will not embed the framework on pod install (before any build phases can generate) if the dylib does not exist.
debug_framework_dir = File.join(flutter_root, 'bin', 'cache', 'artifacts', 'engine', 'ios')
FileUtils.mkdir_p(engine_dir)
FileUtils.cp_r(File.join(debug_framework_dir, 'Flutter.framework'), engine_dir)
FileUtils.cp(File.join(debug_framework_dir, 'Flutter.podspec'), engine_dir)
end
# Keep pod path relative so it can be checked into Podfile.lock.
# Process will be run from project directory.
engine_pathname = Pathname.new engine_dir
project_directory_pathname = Pathname.new Dir.pwd
relative = engine_pathname.relative_path_from project_directory_pathname
pod 'Flutter', :path => relative.to_s, :inhibit_warnings => true
end
# Install Flutter plugin pods.
#
# @example
# target 'MyApp' do
# install_flutter_plugin_pods 'my_flutter'
# end
# @param [String] flutter_application_path Path of the root directory of the Flutter module.
# Optional, defaults to two levels up from the directory of this script.
# MyApp/my_flutter/.ios/Flutter/../..
#def install_flutter_plugin_pods(flutter_application_path)
# flutter_application_path ||= File.join('..', '..')
#
# # Keep pod path relative so it can be checked into Podfile.lock.
# # Process will be run from project directory.
# current_directory_pathname = Pathname.new __dir__
# project_directory_pathname = Pathname.new Dir.pwd
# relative = current_directory_pathname.relative_path_from project_directory_pathname
# pod 'FlutterPluginRegistrant', :path => File.join(relative, 'FlutterPluginRegistrant'), :inhibit_warnings => true
#
# symlinks_dir = File.join(relative, '.symlinks')
# FileUtils.mkdir_p(symlinks_dir)
# plugin_pods = parse_KV_file(File.join(flutter_application_path, '.flutter-plugins'))
# plugin_pods.map do |r|
# symlink = File.join(symlinks_dir, r[:name])
# FileUtils.rm_f(symlink)
# File.symlink(r[:path], symlink)
# pod r[:name], :path => File.join(symlink, 'ios'), :inhibit_warnings => true
# end
#end
# Install Flutter application pod.
#
# @example
# target 'MyApp' do
# install_flutter_application_pod '../flutter_settings_repository'
# end
# @param [String] flutter_application_path Path of the root directory of the Flutter module.
# Optional, defaults to two levels up from the directory of this script.
# MyApp/my_flutter/.ios/Flutter/../..
def install_flutter_application_pod(flutter_application_path)
app_framework_dir = File.join(__dir__, 'App.framework')
app_framework_dylib = File.join(app_framework_dir, 'App')
if !File.exist?(app_framework_dylib)
# Fake an App.framework to have something to link against if the xcode backend script has not run yet.
# CocoaPods will not embed the framework on pod install (before any build phases can run) if the dylib does not exist.
# Create a dummy dylib.
FileUtils.mkdir_p(app_framework_dir)
`echo "static const int Moo = 88;" | xcrun clang -x c -dynamiclib -o "#{app_framework_dylib}" -`
end
# Keep pod and script phase paths relative so they can be checked into source control.
# Process will be run from project directory.
current_directory_pathname = Pathname.new __dir__
project_directory_pathname = Pathname.new Dir.pwd
relative = current_directory_pathname.relative_path_from project_directory_pathname
pod 'flutter_module', :path => relative.to_s, :inhibit_warnings => true
# flutter_export_environment_path = File.join('${SRCROOT}', relative, 'flutter_export_environment.sh');
# script_phase :name => 'Run Flutter Build Script',
# :script => "set -e\nset -u\nsource \"#{flutter_export_environment_path}\"\n../xcode_backend.sh build",
## :script => "set -e\nset -u\nsource \"#{flutter_export_environment_path}\"\n\"$FLUTTER_ROOT\"/packages/flutter_tools/bin/xcode_backend.sh build",
#
# :input_files => [
# File.join('${SRCROOT}', flutter_application_path, '.metadata'),
# File.join('${SRCROOT}', relative, 'App.framework', 'App'),
# File.join('${SRCROOT}', relative, 'engine', 'Flutter.framework', 'Flutter'),
# flutter_export_environment_path
# ],
# :execution_position => :before_compile
end
#def parse_KV_file(file, separator='=')
# file_abs_path = File.expand_path(file)
# if !File.exists? file_abs_path
# return [];
# end
# pods_array = []
# skip_line_start_symbols = ["#", "/"]
# File.foreach(file_abs_path) { |line|
# next if skip_line_start_symbols.any? { |symbol| line =~ /^\s*#{symbol}/ }
# plugin = line.split(pattern=separator)
# if plugin.length == 2
# podname = plugin[0].strip()
# path = plugin[1].strip()
# podpath = File.expand_path("#{path}", file_abs_path)
# pods_array.push({:name => podname, :path => podpath});
# else
# puts "Invalid plugin specification: #{line}"
# end
# }
# return pods_array
#end
#def flutter_root
# generated_xcode_build_settings = parse_KV_file(File.join(__dir__, 'Generated.xcconfig'))
# if generated_xcode_build_settings.empty?
# puts "Generated.xcconfig must exist. Make sure `flutter pub get` is executed in the Flutter module."
# exit
# end
# generated_xcode_build_settings.map { |p|
# if p[:name] == 'FLUTTER_ROOT'
# return p[:path]
# end
# }
#end
解释一下，这个脚本未注释的部分做了两件事：
- 引入Flutter引擎
install_flutter_engine_pod - 引入Flutter工程编译后的Framework，
install_flutter_application_pod
如果是执行
flutter build ios --debug会把这个脚本里的已注释代码部分取消注释。原因是release模式会把第三方库的东西都统一编译到App.framework内，debug不会，所以在debug时会把第三方库分别引入。
方案
综上，我们的方案步骤如下：
在flutter_module工程里执行
flutter build ios --release方法，在工程目录里找到.ios文件夹复制出来Flutter文件夹下的engine目录，App.framework及flutter module的podspec文件。
将app.framework及podspec放入一个文件夹，engine放入另一个文件夹。
-
podfile里面添加
pod 'Flutter', :path => 'path to engine' pod 'flutter module 的name', :path => 'path to app.framework'
执行pod install就好了
此外，也可以把这两个pod库放入git仓库等进行管理。
参考文章：
Flutter远程依赖简单实践
Flutter iOS 混合工程自动化
欢迎大家拍砖
