设备ID未捕获错误：在NPObject上调用方法时出错

Question

我正在尝试将设备ID显示在javascript中，但是我收到了上述错误。我正在使用android studio。我能够获得getState值没有问题。我是机器人的菜鸟。任何帮助，将不胜感激。这是我的代码

MainActivity.java

import android.os.Bundle;
import org.apache.cordova.*;
import org.apache.cordova.device.Device;
import android.provider.Settings.Secure;
import android.webkit.WebChromeClient;
import android.webkit.WebView;
import android.webkit.WebViewClient;

import android.content.Context;
import android.webkit.JavascriptInterface;

public class MainActivity extends CordovaActivity
{
@Override
public void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);

    WebView webview = new WebView(this);
    setContentView(webview);
    webview.getSettings().setJavaScriptEnabled(true);
    webview.setWebChromeClient(new WebChromeClient());


    webview.addJavascriptInterface(new HelperClass(),"device");

    webview.loadUrl("file:///android_asset/www/index.html");


    webview.setWebViewClient(new WebViewClient() {
        public void onPageFinished(WebView view, String loc) {

            String value = "some val";
            String template = "javascript:runme('%s')";

            String thisout = String.format(template, value);
            view.loadUrl(thisout);
        }

    });

}
}

HelperClass.java

import android.content.Context;
import android.provider.Settings;
import android.provider.Settings.Secure;
import android.telephony.TelephonyManager;
import android.util.Log;
 import android.webkit.JavascriptInterface;
import java.util.UUID;

import org.apache.cordova.CordovaActivity;


public class HelperClass extends CordovaActivity{

public int state = 4;

// All the methods that you want to expose to Javascript will go here.
@JavascriptInterface
public int getState(){
     return this.state;
}


@JavascriptInterface
public String getDuid() {
    TelephonyManager TM = (TelephonyManager)           getSystemService(Context.TELEPHONY_SERVICE);
    // IMEI No.
    String imeiNo = TM.getDeviceId();
    // IMSI No.
    String imsiNo = TM.getSubscriberId();
    // SIM Serial No.
    String simSerialNo  = TM.getSimSerialNumber();
    Log.d("Device ID",imeiNo);

    return imeiNo;
}

}//end of class

的index.html

<div class="app">        
    <input type="text" id="myText">
    <input type="text" id="myVal">
    <button onclick="runme('test');">Run me</button>
</div>

<script type="text/javascript">

    function runme(txt){
        document.getElementById("myText").value = "output is "+txt;
        alert('i ran');
        document.getElementById("myVal").value = window.device.getDuid();
    }
    document.addEventListener("deviceready", function(){

    });

</script>