How to call my activity in unity project?

How to call my activity in unity project.
I made an android project plugin(jar) and i will call startActivity of that.
This activity recieve the intent and show the webview when it starts.
I will try below with C#, but i can not success in unity project.

1. I made the class extends UnityPlayerActivity in my plugin.
   example:

   public static UnityPlayerActivity Instance;
   public void onCreate(Bundle savedInstanceState) {
   super.onCreate(savedInstanceState);
   Instance = this;
   Intent intent = new Intent(UnityPlayer.currentActivity, myClass(this));
   UnityPlayer.currentActivity.startActivity(intent);
   }

2. I call an activity in unity project with C#.
   example:
   

   AndroidJavaClass cls = new AndroidJavaClass(package name .my class name);
   AndroidJavaObject obj = cls.GetStatic(cls);
   obj.Call("startActivity" , parameter);
   

I would appriciate it if you could reply to my question.