How to make separate class for volley library and call all method of volley from another activity and get response?

Question

how to create a separate class in which define all about volley and in another activity we directly pass URL,CONTEXT and Get Response...

Answer 1

First create callback interface to get result in Activity

public interface IResult {
    public void notifySuccess(String requestType,JSONObject response);
    public void notifyError(String requestType,VolleyError error);
}

Create a separate class with volley function to response the result through interface to activity

public class VolleyService {

    IResult mResultCallback = null;
    Context mContext;

    VolleyService(IResult resultCallback, Context context){
        mResultCallback = resultCallback;
        mContext = context;
    }


    public void postDataVolley(final String requestType, String url,JSONObject sendObj){
        try {
            RequestQueue queue = Volley.newRequestQueue(mContext);

            JsonObjectRequest jsonObj = new JsonObjectRequest(url,sendObj, new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {
                    if(mResultCallback != null)
                        mResultCallback.notifySuccess(requestType,response);
                }
            }, new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    if(mResultCallback != null)
                        mResultCallback.notifyError(requestType,error);
                }
            });

            queue.add(jsonObj);

        }catch(Exception e){

        }
    }

    public void getDataVolley(final String requestType, String url){
        try {
            RequestQueue queue = Volley.newRequestQueue(mContext);

            JsonObjectRequest jsonObj = new JsonObjectRequest(Request.Method.GET, url, new Response.Listener<JSONObject>() {
                @Override
                public void onResponse(JSONObject response) {
                    if(mResultCallback != null)
                        mResultCallback.notifySuccess(requestType, response);
                }
            }, new Response.ErrorListener() {
                @Override
                public void onErrorResponse(VolleyError error) {
                    if(mResultCallback != null)
                        mResultCallback.notifyError(requestType, error);
                }
            });

            queue.add(jsonObj);

        }catch(Exception e){

        }
    }
} 

Then initialize callback interface into main activity

    mResultCallback = new IResult() {
        @Override
        public void notifySuccess(String requestType,JSONObject response) {
            Log.d(TAG, "Volley requester " + requestType);
            Log.d(TAG, "Volley JSON post" + response);
        }

        @Override
        public void notifyError(String requestType,VolleyError error) {
            Log.d(TAG, "Volley requester " + requestType);
            Log.d(TAG, "Volley JSON post" + "That didn't work!");
        }
    };

Now create object of VolleyService class and pass it context and callback interface

mVolleyService = new VolleyService(mResultCallback,this);

Now call the Volley method for post or get data also pass requestType which is to identify the service requester when getting result back into main activity

    mVolleyService.getDataVolley("GETCALL","http://192.168.1.150/datatest/get/data");
    JSONObject sendObj = null;

    try {
        sendObj = new JSONObject("{'Test':'Test'}");
    } catch (JSONException e) {
        e.printStackTrace();
    }
    mVolleyService.postDataVolley("POSTCALL", "http://192.168.1.150/datatest/post/data", sendObj);

Final MainActivity

public class MainActivity extends AppCompatActivity {
    private String TAG = "MainActivity";
    IResult mResultCallback = null;
    VolleyService mVolleyService;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        initVolleyCallback();
        mVolleyService = new VolleyService(mResultCallback,this);
        mVolleyService.getDataVolley("GETCALL","http://192.168.1.150/datatest/get/data");
        JSONObject sendObj = null;

        try {
            sendObj = new JSONObject("{'Test':'Test'}");
        } catch (JSONException e) {
            e.printStackTrace();
        }
        mVolleyService.postDataVolley("POSTCALL", "http://192.168.1.150/datatest/post/data", sendObj);
    }

    void initVolleyCallback(){
        mResultCallback = new IResult() {
            @Override
            public void notifySuccess(String requestType,JSONObject response) {
                Log.d(TAG, "Volley requester " + requestType);
                Log.d(TAG, "Volley JSON post" + response);
            }

            @Override
            public void notifyError(String requestType,VolleyError error) {
                Log.d(TAG, "Volley requester " + requestType);
                Log.d(TAG, "Volley JSON post" + "That didn't work!");
            }
        };
    }

}

Find the whole project at following link

https://github.com/PatilRohit/VolleyCallback

Answer 2

JsonParserVolley.java

(A separate class where we will get the response)

public class JsonParserVolley {

final String contentType = "application/json; charset=utf-8";
String JsonURL = "Your URL";
Context context;
RequestQueue requestQueue;
String jsonresponse;

private Map<String, String> header;

public JsonParserVolley(Context context) {
    this.context = context;
    requestQueue = Volley.newRequestQueue(context);
    header = new HashMap<>();

}

public void addHeader(String key, String value) {
    header.put(key, value);
}

public void executeRequest(int method, final VolleyCallback callback) {

    StringRequest stringRequest = new StringRequest(method, JsonURL, new Response.Listener<String>() {
        @Override
        public void onResponse(String response) {
            jsonresponse = response;
            Log.e("RES", " res::" + jsonresponse);
            callback.getResponse(jsonresponse);


        }
    }, new Response.ErrorListener() {
        @Override
        public void onErrorResponse(VolleyError error) {

        }
    }) {
        @Override
        public Map<String, String> getHeaders() throws AuthFailureError {

            return header;
        }
    }
    ;
    requestQueue.add(stringRequest);

}

public interface VolleyCallback
{
    public void getResponse(String response);
}

}

MainActivity.java (Code Snippet written in onCreate method)

final JsonParserVolley jsonParserVolley = new JsonParserVolley(this);
    jsonParserVolley.addHeader("Authorization", "Your value");
    jsonParserVolley.executeRequest(Request.Method.GET, new JsonParserVolley.VolleyCallback() {

        @Override
        public void getResponse(String response) {

            jObject=response;
            Log.d("VOLLEY","RES"+jObject);

            parser();
        }
    }
    );

parser() is the method where the json response obtained is used to bind with the components of the activity.

Answer 3

you actually missed one parameter in the above VolleyService class. You needed to include, it is,... JsonObjectRequest jsonObj = new JsonObjectRequest(Request.Method.GET, url,null,new Response.Listener() { /..../ } null is the parameter should be included else it gives error