Java Android:actionbar上的Webview刷新按钮

我有一些片段（它们只打开带有webview的网站）。我想在ActionBar的右边添加一个刷新按钮，它应该只刷新当前片段的webview。我创建了menu_main.xml、drawable图标等，但我不能在片段上使用它。这里是我的失败代码

package net.xxxxx.ccccc;
import android.app.Activity;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.Menu;
import android.view.MenuInflater;
import android.view.MenuItem;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebSettings;
import android.webkit.WebView;
import android.webkit.WebViewClient;

import static net.xxxxx.ccccc.R.id.vwVatan;

public class VatanFragment extends Fragment {

    Activity titleChange;

    public VatanFragment() {
        // Required empty public constructor
    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        View vtn = inflater.inflate(R.layout.fragment_vatan, container, false);
        WebView webVatan = (WebView) vtn.findViewById(vwVatan);
        WebSettings webSettings6 = webVatan.getSettings();
        webSettings6.setJavaScriptEnabled(true);
        webVatan.loadUrl("http://www.somesite.com/");
        webVatan.setWebViewClient(new WebViewClient());
        titleChange.setTitle("Vatan");
        return vtn;
    }

    @Override
    public void onAttach(Activity activity) {
        super.onAttach(activity);

        titleChange = (MainActivity) activity;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {

    WebView wvVatan = (WebView) vtn.getChildAt();
        switch (item.getItemId()){
            case R.id.refresh:
                vwVatan.reload();
                return true;
        }
    }
}