Type mismatch: inferred type is Activity? but Context was expected

kt 编译运行错误

Running Gradle task 'assembleDebug'...
e: /home/leon/AndroidStudioProjects/samples/kkview_chuan/plugins/flutter_app_upgrade/android/src/main/kotlin/com/flutter/flutter_app_upgrade/FlutterAppUpgradePlugin.kt: (51, 23): Type mismatch: inferred type is Activity? but Context was expected

FAILURE: Build failed with an exception.

* What went wrong:
Execution failed for task ':flutter_app_upgrade:compileDebugKotlin'.
> A failure occurred while executing org.jetbrains.kotlin.compilerRunner.GradleCompilerRunnerWithWorkers$GradleKotlinCompilerWorkAction
   > Compilation error. See log for more details

* Try:
> Run with --stacktrace option to get the stack trace.
> Run with --info or --debug option to get more log output.
> Run with --scan to get full insights.

* Get more help at https://help.gradle.org

BUILD FAILED in 3s
Exception: Gradle task assembleDebug failed with exit code 1

解决方法：
this.mContext = registrar.activity() 改为：this.mContext = registrar.context()

  companion object {
    
    
    lateinit var mContext: Context

    @JvmStatic
    fun registerWith(registrar: Registrar) {
    
    
      this.mContext = registrar.activity()
      val channel = MethodChannel(registrar.messenger(), "the_app")
      channel.setMethodCallHandler(FlutterAppUpgradePlugin())
    }

  }