Unable to find activity in manifest

I’m trying to write Android plugin that will open WiFi Settings window.
Here is my activity.

package com.example.wificonnector;

import android.content.Intent;
import android.net.wifi.WifiManager;
import android.os.Bundle;

import com.unity3d.player.UnityPlayerActivity;

public class MainActivity extends UnityPlayerActivity
	protected void onCreate(Bundle savedInstanceState) 
	public void OpenWiFiSettings()
		startActivity(new Intent(WifiManager.ACTION_PICK_WIFI_NETWORK));

Here is manifest

And now,when I’m trying to start my app on device I have this mistakes:

What am I doing wrong?

I agree with ina.
But I found solution.The problem was with workaround of Java classes.If you want to init class from Java library,do it in Start(),not before.