Flutter中file_picker插件编译失败问题求助

使用file_picker插件时遭遇编译失败，具体报错信息如下：

/Users/mycomputer/.pub-cache/hosted/pub.dev/file_picker-8.1.5/android/src/main/java/com/mr/flutter/plugin/filepicker/FilePickerPlugin.java:257: error: cannot find symbol
    if (registrar!= null) {
        ^
   symbol:   variable registrar
   location: class FilePickerPlugin
   /Users/mycomputer/.pub-cache/hosted/pub.dev/file_picker-8.1.5/android/src/main/java/com/mr/flutter/plugin/filepicker/FilePickerPlugin.java:260: error: cannot find symbol
          registrar.addActivityResultListener(this.delegate);
          ^
  symbol:   variable registrar
  location: class FilePickerPlugin
2 errors

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':file_picker:compileDebugJavaWithJavac'.
> Compilation failed; see the compiler error output for details.

已尝试以下操作但问题未解决：

• 删除.gradle文件
• 更换file_picker版本

恳请技术支持。

内容的提问来源于stack exchange，提问作者Alpit Panchal