使用fat-aar(com.kezong.fat-aar) 配合flutter package項目生成nativie項目中間件aar

1，.android項目內跟目錄的build.gradle 添加如下：

dependencies {
classpath 'com.android.tools.build:gradle:3.2.1'
// classpath "com.mobbeel.plugin:fat-aar:2.0.3"http://這個使用出現bug
classpath 'com.kezong:fat-aar:1.1.7'//fat arr打包arr中間件
}

2,.android項目內Flutter/build.gradle

加入 apply plugin: 'com.kezong.fat-aar'
dependencies 加入依賴插件 例如：
embed project(path: ':connectivity', configuration:'default')
embed project(path: ':flutter_statusbar', configuration:'default')
embed project(path: ':fluttertoast', configuration:'default')
embed project(path: ':path_provider', configuration:'default')
embed project(path: ':shared_preferences', configuration:'default')
embed project(path: ':url_launcher', configuration:'default')

3，執行命令 flutter build apk

打印部分信息如下：
【Fat-aar-INFO】[embed detected][aar]io.flutter.plugins.connectivity:connectivity:1.0-SNAPSHOT
【Fat-aar-INFO】[embed detected][aar]com.example.flutterstatusbar:flutter_statusbar:1.0-SNAPSHOT
【Fat-aar-INFO】[embed detected][aar]io.github.ponnamkarthik.toast.fluttertoast:fluttertoast:1.0-SNAPSHOT
【Fat-aar-INFO】[embed detected][aar]io.flutter.plugins.pathprovider:path_provider:1.0-SNAPSHOT
【Fat-aar-INFO】[embed detected][aar]io.flutter.plugins.sharedpreferences:shared_preferences:1.0-SNAPSHOT
【Fat-aar-INFO】[embed detected][aar]io.flutter.plugins.urllauncher:url_launcher:1.0-SNAPSHOT
【Fat-aar-INFO】Merge resource，Library res：/Users/conghl/flutter/.android/Flutter/build/intermediates/exploded-aar/com.example.flutterstatusbar/flutter_statusbar/1.0-SNAPSHOT/res
【Fat-aar-INFO】Merge resource，Library res：/Users/conghl/flutter/.android/Flutter/build/intermediates/exploded-aar/io.flutter.plugins.pathprovider/path_provider/1.0-SNAPSHOT/res
【Fat-aar-INFO】Merge resource，Library res：/Users/conghl/flutter/.android/Flutter/build/intermediates/exploded-aar/io.github.ponnamkarthik.toast.fluttertoast/fluttertoast/1.0-SNAPSHOT/res
【Fat-aar-INFO】Merge resource，Library res：/Users/conghl/flutter/.android/Flutter/build/intermediates/exploded-aar/io.flutter.plugins.urllauncher/url_launcher/1.0-SNAPSHOT/res
【Fat-aar-INFO】Merge resource，Library res：/Users/conghl/flutter/.android/Flutter/build/intermediates/exploded-aar/io.flutter.plugins.connectivity/connectivity/1.0-SNAPSHOT/res
【Fat-aar-INFO】Merge resource，Library res：/Users/conghl/flutter/.android/Flutter/build/intermediates/exploded-aar/io.flutter.plugins.sharedpreferences/shared_preferences/1.0-SNAPSHOT/res
【Fat-aar-INFO】Merge classes
【Fat-aar-INFO】[androidLibrary]flutter_statusbar
【Fat-aar-INFO】[androidLibrary]path_provider
【Fat-aar-INFO】[androidLibrary]fluttertoast
【Fat-aar-INFO】[androidLibrary]url_launcher
【Fat-aar-INFO】[androidLibrary]connectivity
【Fat-aar-INFO】[androidLibrary]shared_preferences
【Fat-aar-INFO】Merge jars
【Fat-aar-INFO】Not found jar file, Library:flutter_statusbar
【Fat-aar-INFO】Not found jar file, Library:path_provider
【Fat-aar-INFO】Not found jar file, Library:fluttertoast
【Fat-aar-INFO】Not found jar file, Library:url_launcher
【Fat-aar-INFO】Not found jar file, Library:connectivity
【Fat-aar-INFO】Not found jar file, Library:shared_preferences
【Fat-aar-INFO】Generate R File, Library:flutter_statusbar
【Fat-aar-INFO】Generate R File, Library:path_provider
【Fat-aar-INFO】Generate R File, Library:fluttertoast
【Fat-aar-INFO】Generate R File, Library:url_launcher
【Fat-aar-INFO】Generate R File, Library:connectivity
【Fat-aar-INFO】Generate R File, Library:shared_preferences
【Fat-aar-INFO】Compile R.class, Dir:/Users/conghl/flutter/.android/Flutter/build/intermediates/exploded-aar/r
【Fat-aar-INFO】Generate R.jar, Dir：/Users/conghl/flutter/.android/Flutter/build/intermediates/exploded-aar/r-class
【Fat-aar-INFO】reBundle final aar, from:/Users/conghl/flutter/.android/Flutter/build/outputs/aar-R/release
【Fat-aar-INFO】reBundle final aar, target:/Users/conghl/flutter/.android/Flutter/build/outputs/aar/flutter-release.aar

4，最后一行內的文件即為android中間件文件，拷貝到native項目libs文件內。

D8: Program type already present: ******
出現這個錯誤將.android/Flutter/build 文件刪除重新編譯即可

native項目修改

1，將aar文件拷貝到libs文件內
2，app/build.gradle

dependencies {
  ...
    api(name: 'flutter-release', ext: 'aar')
  ...
  ...
}

3，project/build.gradle

allprojects {
    repositories {
      ......
        flatDir {
            dirs 'libs'   // aar目錄
        }
      ......
    }
}

使用另一個aar(fataar-gradle-plugin)問題,編譯重視失敗最后嘗試也沒成功，浪費很長時間 放棄了。
https://github.com/flutter/flutter/issues/18025
https://github.com/flutter/flutter/issues/23944

多渠道aar: flutter build apk --flavor XXX