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!

Diekrul Diekrul · Accepted Answer · 2017-02-12T21:30:25

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);

}

AsyncHttpClient LoopJ and preserving data from onSuccess method

1 Answers