AsyncHttpClient LoopJ and preserving data from onSuccess method

Question

I have this method called "invokeWS". All I want to is to do is to update an ArrayAdapter adapter2 I use in my app with the listdata ArrayList that gets data from a JSON file. I tried different things.

• The onSuccess is void, so I cannot return anything to the main program. I am good to go inside the try, JSON is parsed and I can see the strings I want in the console but as soon as I get out of the onSuccess, I get an empty Arraylist. So when returning the listdata is empty.
• Had to also declare the listdata "final", otherwise errors of "accessed from inner class" would appear wherever listdata is on OnSuccess
• Also Tried to make the ArrayAdapter adapter2 to be updated inside onSuccess but didn't work because it is said it is out of scope.

• I was going to implement onFinish method, but it even got called before JSON was parsed for a strange reason.

  public static ArrayList<String> invokeWS() {
  AsyncHttpClient client = new AsyncHttpClient();
  final  ArrayList<String>  listdata = new ArrayList<String>();
  client.get("http://xxx.xxx.xxx.xxx:8085/CompanyJersWS/company/showcompany", new  JsonHttpResponseHandler() {  //address to be specified each time, using external IP address
  
  
              @Override
              public void onSuccess(int statusCode, Header[] headers, JSONObject response) {
                  System.out.println("Inside Success invokeWS");
                  try {
                      JSONArray json = response.getJSONArray("Companies");
                      System.out.println("JSON is parsed!" +json.toString() + "Length is " + json.length());
                      System.out.println("First value is " + json.getString(0));
                      int i;
                      for (i=0;i<json.length();i++)
                          listdata.add(json.getString(i));
                      System.out.println("Listdata contains" +listdata);
  
  
                  } catch (Exception e) {
                      System.out.println("FAILED invokeWS");
                      e.printStackTrace();
                  }
              }
          }
  
  
  
  );
  
  System.out.println("Listdata out of scope contains" +listdata);
  
  return listdata;
  
  }
  

  This is how I am trying to call invokeWS() from my main class;

  ArrayList<String> tempval = invokeWS();
  

  and this is the adapter2 written in main class, which i want to have listdata from json file as contents.

  ArrayAdapter<String> adapter2 = new ArrayAdapter<String>(this,
          android.R.layout.simple_spinner_item, tempval.toArray(new String[tempval.size()]));
   sp1.setAdapter(adapter2);
  

Thanks for reading!

Answer 1

Something you can do is, after onSuccess pass the "listdata" that you create like a parameter of a function (for example "refreshData"):

    @Override
        public void onSuccess(int statusCode, Header[] headers, JSONObject response) {
            System.out.println("Inside Success invokeWS");
            try {
                JSONArray json = response.getJSONArray("Companies");
                System.out.println("JSON is parsed!" +json.toString() + "Length is " + json.length());
                System.out.println("First value is " + json.getString(0));
                int i;
                for (i=0;i<json.length();i++){
                    listdata.add(json.getString(i));
                 }
             System.out.println("Listdata contains" +listdata);
             refreshData(listdata);
             } catch (Exception e) {
                System.out.println("FAILED invokeWS");
                e.printStackTrace();
             }

        }

And then use that function to update the array with the new list:

public void refreshData(ArrayList<String> listdata){
    ArrayAdapter<String> adapter2 = new ArrayAdapter<String>(this,
    android.R.layout.simple_spinner_item, listdata);
   sp1.setAdapter(adapter2);

}