webview运用和传值

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.widget.Toast;


import com.example.lx.R;




@SuppressLint("JavascriptInterface")
public class Frag3 extends Fragment{
private WebView wv;


@Override
public View onCreateView(LayoutInflater inflater,
@Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View view = inflater.inflate(R.layout.frag3, container, false);
wv = (WebView) view.findViewById(R.id.wv);
wv.loadUrl("file:///android_asset/as.html");
wv.getSettings().setDefaultTextEncodingName("utf-8");
wv.getSettings().setJavaScriptEnabled(true);
wv.setWebChromeClient(new WebChromeClient());
wv.addJavascriptInterface(new MyInterface(), "usb");
return view;
}
class MyInterface{

@JavascriptInterface

public void Text(String name,String pwd){
Toast.makeText(getActivity(), name+pwd, 1).show();
}
}

}

<WebView 
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     android:id="@+id/wv"
     />

//网页

usb.Text(vname,vpwd);