How to run cordova plugin in Android background service?

[meshen mehsen]

I am working on mobile application developed on cordova . I want to implement a background service that do some work like open socket connection syncronise local database with remote one and notify the users on new remote pushes etc . The point is I have this code implemented in javascript but I want execute it i background.

I searched internet for a cordova background service plugin.

 - katzer/cordova-plugin-background-mode

 - jocull/phonegap-backgroundjs

 - red-folder

 The best one I think is red-folder but it is just for android and it does not let me to write javascript to be executed in background. but just exchange json between java and javascript.

I have read some topics about background service in android these are useful ones I found:

 - create-a-service-on-android-with-phonegap-application

 - simple-android-service-example-code-description-start-stop-service

 - android-using-webview-outside-an-activity-context

So I started writing cordova plugin (primarily on android) to execute the javascript code in background. I created a webview from the background service to execute the javascript from it. This works fine when I execute normal javascript but when it comes to cordova plugins js it fails for example the device `device.uuid` gives `null`.

This is the java service  code:

         

public void onStart(Intent intent, int startId) {
         Toast.makeText(this, "My Happy Service Started", Toast.LENGTH_LONG).show();
       
               createBackGroundView();
               super.onStart(intent,startId);
    }




          public void createBackGroundView(){
   
             
        WindowManager windowManager = (WindowManager) getSystemService(WINDOW_SERVICE);
       LayoutParams params = new WindowManager.LayoutParams(
                       android.view.ViewGroup.LayoutParams.WRAP_CONTENT,
                       android.view.ViewGroup.LayoutParams.WRAP_CONTENT,
                       WindowManager.LayoutParams.TYPE_PHONE,
                       WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE,
                       PixelFormat.TRANSLUCENT
               );
             
        params.gravity = Gravity.TOP | Gravity.LEFT;
        params.x = 0;
        params.y = 0;
        params.width = 200;
        params.height = 200;
       
        LinearLayout view = new LinearLayout(this);
               
        view.setLayoutParams(new RelativeLayout.LayoutParams(
                        android.view.ViewGroup.LayoutParams.MATCH_PARENT,
                        android.view.ViewGroup.LayoutParams.MATCH_PARENT
                ));
               
        WebView wv = new WebView(this);
        wv.setLayoutParams(new LinearLayout.LayoutParams(
                        android.view.ViewGroup.LayoutParams.MATCH_PARENT,
                        android.view.ViewGroup.LayoutParams.MATCH_PARENT
                ));    
        view.addView(wv);
        wv.getSettings().setJavaScriptEnabled(true);
        wv.setWebChromeClient(new WebChromeClient());
                wv.loadUrl("file:///android_asset/www/background.html");
        wv.setWebViewClient(new WebViewClient() {
 
 @Override
 public void onReceivedError(final WebView view, int errorCode,
 String description, final String failingUrl) {
 Log.d("Error","loading web view");
 super.onReceivedError(view, errorCode, description, failingUrl);
 }
 });


        windowManager.addView(view, params);
     
         }

There is no error in the logcat.

So I tried to write the device object on the screen and thats what I get :

       

     

   

   document.write(JSON.stringify(window.device))

And this is the result :

   

   { available : false,
        plaform : null ,
        version : null ,
        uuid : null ,  
        cordova : null ,
        model : null
       }

Any help about this problem ?

 

[Çetin DOĞU]

Hello Mehsen,

you can run JS code in background on android platform via BackgroundJS. 

add this settings to your config.xml file;

  <feature name="BackgroundJS">

    <param name="ios-package" value="BackgroundJS" />

  </feature>

 <gap:plugin name="com.badrit.backgroundjs" version="0.1.0" />  

  <gap:plugin name="org.apache.cordova.device" version="0.2.3" />