Flutter插件permission_handler获取权限不

如果往已有的iOS工程中，集成Flutter Module。Flutter Module中又集成了permission_handler，来获取各种权限。那么你会遇到各种权限都是denied，即使你已经开启授权。即使你按照官网配置iOS工程，还是如此。

原因是官方配置只适用纯Flutter App，如果是iOS嵌入Flutter模块不适合官网配置

• 官方配置【适用于纯Flutter App，iOS嵌入Flutter不适用！！！】点击跳转官网

post_install do |installer|
  installer.pods_project.targets.each do |target|
    target.build_configurations.each do |config|
      ... # Here are some configurations automatically generated by flutter

      # You can enable the permissions needed here. For example to enable camera
      # permission, just remove the `#` character in front so it looks like this:
      #
      # ## dart: PermissionGroup.camera
      # 'PERMISSION_CAMERA=1'
      #
      #  Preprocessor definitions can be found in: https://github.com/Baseflow/flutter-permission-handler/blob/master/permission_handler/ios/Classes/PermissionHandlerEnums.h
      config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] ||= [
        '$(inherited)',

        ## dart: PermissionGroup.calendar
        # 'PERMISSION_EVENTS=1',

        ## dart: PermissionGroup.reminders
        # 'PERMISSION_REMINDERS=1',

        ## dart: PermissionGroup.contacts
        # 'PERMISSION_CONTACTS=1',

        ## dart: PermissionGroup.camera
        # 'PERMISSION_CAMERA=1',

        ## dart: PermissionGroup.microphone
        # 'PERMISSION_MICROPHONE=1',

        ## dart: PermissionGroup.speech
        # 'PERMISSION_SPEECH_RECOGNIZER=1',

        ## dart: PermissionGroup.photos
        # 'PERMISSION_PHOTOS=1',

        ## dart: [PermissionGroup.location, PermissionGroup.locationAlways, PermissionGroup.locationWhenInUse]
        # 'PERMISSION_LOCATION=1',

        ## dart: PermissionGroup.notification
        # 'PERMISSION_NOTIFICATIONS=1',

        ## dart: PermissionGroup.mediaLibrary
        # 'PERMISSION_MEDIA_LIBRARY=1',

        ## dart: PermissionGroup.sensors
        # 'PERMISSION_SENSORS=1',   

        ## dart: PermissionGroup.bluetooth
        # 'PERMISSION_BLUETOOTH=1',

        ## dart: PermissionGroup.appTrackingTransparency
        # 'PERMISSION_APP_TRACKING_TRANSPARENCY=1',

        ## dart: PermissionGroup.criticalAlerts
        # 'PERMISSION_CRITICAL_ALERTS=1'
      ]

    end
  end
end

• 非官方配置【适用于Flutter Module的工程配置】，添加以下代码到iOS主项目的Podfile文件中！

post_install do |installer|
  installer.pods_project.targets.each do |target|
    target.build_configurations.each do |config|
      config.build_settings['ENABLE_BITCODE'] = 'YES'
#      config.build_settings['IPHONEOS_DEPLOYMENT_TARGET'] = '11.0'
#      config.build_settings["EXCLUDED_ARCHS"] = "armv7"
    end
    if target.name == "permission_handler"
      target.build_configurations.each do |config|
        config.build_settings['GCC_PREPROCESSOR_DEFINITIONS'] ||= [
                    '$(inherited)',

                    ## dart: PermissionGroup.calendar
                    'PERMISSION_EVENTS=1',

                    ## dart: PermissionGroup.reminders
                    # 'PERMISSION_REMINDERS=1',

                    ## dart: PermissionGroup.contacts
                    # 'PERMISSION_CONTACTS=1',

                    ## dart: PermissionGroup.camera
                    # 'PERMISSION_CAMERA=1',

                    ## dart: PermissionGroup.microphone
                    # 'PERMISSION_MICROPHONE=1',

                    ## dart: PermissionGroup.speech
                    # 'PERMISSION_SPEECH_RECOGNIZER=1',

                    ## dart: PermissionGroup.photos
                    # 'PERMISSION_PHOTOS=1',

                    ## dart: [PermissionGroup.location, PermissionGroup.locationAlways, PermissionGroup.locationWhenInUse]
                    # 'PERMISSION_LOCATION=1',

                    ## dart: PermissionGroup.notification
                    # 'PERMISSION_NOTIFICATIONS=1',

                    ## dart: PermissionGroup.mediaLibrary
                    # 'PERMISSION_MEDIA_LIBRARY=1',

                    ## dart: PermissionGroup.sensors
                    # 'PERMISSION_SENSORS=1',

                    ## dart: PermissionGroup.bluetooth
                    # 'PERMISSION_BLUETOOTH=1',

                    ## dart: PermissionGroup.appTrackingTransparency
                    # 'PERMISSION_APP_TRACKING_TRANSPARENCY=1',

                    ## dart: PermissionGroup.criticalAlerts
                    # 'PERMISSION_CRITICAL_ALERTS=1'
                  ]
        end
      end
    end
  end

问题解决了，休息下。回来思考：为什么要这样配置？

3b9c58166c9be1b9a2e0c164eb53f851.jpeg

原理：我们都知道，Flutter调用原生的API需要通过插件来实现，permission_handler就是获取原生手机权限。

代码跑起来要经过四步 ： 源代码-> 预处理->汇编->链接，然而在预处理缺少的宏定义，不会报错，但是会影响逻辑。
这就是为什么跑起来没问题，权限状态有问题！

permission_handler.jpeg

解决记录：

• 进入permission_handler插件的iOS源码,里面大量逻辑依赖预处理的宏定义。
• 对应Podfile中的GCC_PREPROCESSOR_DEFINITIONS和Xcode Build Settings中的Apple Clang - Preprocessing。要添加对应的宏定义，才能正确运行。
• 添加到Podfile中，每次执行pod install会自动配置到 Xcode Build Settings中。
• Podfile中奇怪的语法其实是Ruby语言写的。

// 如果没有定义PERMISSION_EVENTS，以下代码就不会执行！

 #if PERMISSION_EVENTS
        return [EventPermissionStrategy permissionStatus:EKEntityTypeEvent];
 #endif