Volley Example

String Request
*********************************************************
String url = "https:// string_url/"; 
StringRequest 
    stringRequest 
    = new StringRequest( 
        Request.Method.GET, 
        url, 
        new Response.Listener() { 
            @Override
            public void onResponse(String response) 
            { 
            } 
        }, 
        new Response.ErrorListener() { 
            @Override
            public void onErrorResponse(VolleyError error) 
            { 
            } 
        }); 
requestQueue.add(stringRequest); 
*****************************************************************************************
JSONObject Request

String url = "https:// json_url/"; 
JsonObjectRequest 
    jsonObjectRequest 
    = new JsonObjectRequest( 
        Request.Method.GET, 
        url, 
        null, 
        new Response.Listener() { 
            @Override
            public void onResponse(JSONObject response) 
            { 
            } 
        }, 
        new Response.ErrorListener() { 
            @Override
            public void onErrorResponse(VolleyError error) 
            { 
            } 
        }); 
requestQueue.add(jsonObjectRequest); 

**************************************************************************************
JSONArray Request

JsonArrayRequest 
    jsonArrayRequest 
    = new JsonArrayRequest( 
        Request.Method.GET, 
        url, 
        null, 
        new Response.Listener() { 
            @Override
            public void onResponse(JSONArray response) 
            { 
            } 
        }, 
        new Response.ErrorListener() { 
            @Override
            public void onErrorResponse(VolleyError error) 
            { 
            } 
        }); 
requestQueue.add(jsonArrayRequest); 
**********************************************************************************************************
Image Request

int max - width = ...; 
int max_height = ...; 
  
String URL = "http:// image_url.png"; 
  
ImageRequest 
    imageRequest 
    = new ImageRequest(URL, 
                       new Response.Listener() { 
                           @Override
                           public void
                           onResponse(Bitmap response) 
                           { 
                               // Assign the response 
                               // to an ImageView 
                               ImageView 
                                   imageView 
                                   = (ImageView) 
                                       findViewById( 
                                           R.id.imageView); 
  
                               imageView.setImageBitmap(response); 
                           } 
                       }, 
                       max_width, max_height, null); 
  
requestQueue.add(imageRequest); 

******************************************************************************************************

Adding Post Parameters

String tag_json_obj = "json_obj_req"; 
  
String 
    url 
    = "https:// api.xyz.info/volley/person_object.json"; 
  
ProgressDialog pDialog = new ProgressDialog(this); 
pDialog.setMessage("Loading...PLease wait"); 
pDialog.show(); 
  
JsonObjectRequest 
    jsonObjReq 
    = new JsonObjectRequest( 
        Method.POST, 
        url, 
        null, 
        new Response.Listener() { 
  
            @Override
            public void onResponse(JSONObject response) 
            { 
                Log.d(TAG, response.toString()); 
                pDialog.hide(); 
            } 
        }, 
        new Response.ErrorListener() { 
  
            @Override
            public void onErrorResponse(VolleyError error) 
            { 
                VolleyLog.d(TAG, "Error: "
                                     + error.getMessage()); 
                pDialog.hide(); 
            } 
        }) { 
  
          @Override
          protected Map getParams() 
          { 
              Map params = new HashMap(); 
              params.put("name", "Androidhive"); 
              params.put("email", "abc@androidhive.info"); 
              params.put("password", "password123"); 
  
              return params; 
          } 
  
      }; 
  
AppController.getInstance() 
    .addToRequestQueue(jsonObjReq, tag_json_obj); 
		****************************************************************************************************************
Adding Request Headers

String tag_json_obj = "json_obj_req"; 
  
String 
    url 
    = "https:// api.androidhive.info/volley/person_object.json"; 
  
ProgressDialog pDialog = new ProgressDialog(this); 
pDialog.setMessage("Loading..."); 
pDialog.show(); 
  
JsonObjectRequest 
    jsonObjReq 
    = new JsonObjectRequest( 
        Method.POST, 
        url, 
        null, 
        new Response.Listener() { 
  
            @Override
            public void onResponse(JSONObject response) 
            { 
                Log.d(TAG, response.toString()); 
                pDialog.hide(); 
            } 
        }, 
        new Response.ErrorListener() { 
  
            @Override
            public void onErrorResponse(VolleyError error) 
            { 
                VolleyLog.d(TAG, "Error: "
                                     + error.getMessage()); 
                pDialog.hide(); 
            } 
        }) { 
  
          @Override
          public Map getHeaders() throws AuthFailureError 
          { 
              HashMap headers = new HashMap(); 
              headers.put("Content-Type", "application/json"); 
              headers.put("apiKey", "xxxxxxxxxxxxxxx"); 
              return headers; 
          } 
  
      }; 
  
AppController.getInstance() 
    .addToRequestQueue(jsonObjReq, tag_json_obj); 
		***************************************************************************************************************
Handling the Volley Cache

// Loading request from cache 
Cache 
    cache 
    = AppController.getInstance() 
          .getRequestQueue() 
          .getCache(); 
  
Entry entry = cache.get(url); 
if (entry != null) { 
    try { 
        String 
            data 
            = new String(entry.data, "UTF-8"); 
        // handle data, like converting it 
        // to xml, json, bitmap etc., 
    } 
    catch (UnsupportedEncodingException e) { 
        e.printStackTrace(); 
    } 
} 
} 
else
{ 
    // If cached response doesn't exists 
} 
  
// Invalidate cache 
AppController.getInstance() 
    .getRequestQueue() 
    .getCache() 
    .invalidate(url, true); 
  
// Turning off cache 
// String request 
StringRequest 
    stringReq 
    = new StringRequest(....); 
  
// disable cache 
stringReq.setShouldCache(false); 
  
// Deleting cache for particular cache</strong> 
AppController.getInstance() 
    .getRequestQueue() 
    .getCache() 
    .remove(url); 
  
// Deleting all the cache 
AppController.getInstance() 
    .getRequestQueue() 
    .getCache() 
    .clear(url); 
Cancelling Request
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// Cancel single request 
String tag_json_arry = "json_req"; 
  
ApplicationController.getInstance() 
    .getRequestQueue() 
    .cancelAll("feed_request"); 
  
// Cancel all request 
ApplicationController.getInstance() 
    .getRequestQueue() 
    .cancelAll(); 
		****************************************************************************************************************
Request Prioritization

private Priority priority = Priority.HIGH; 
  
StringRequest 
    strReq 
    = new StringRequest( 
        Method.GET, 
        Const.URL_STRING_REQ, 
        new Response 
            .Listener() { 
   
                    @Override
                    public void onResponse(String response) { 
  
                        Log.d(TAG, response.toString()); 
                        msgResponse.setText(response.toString()); 
                        hideProgressDialog(); 
   
                    } }, 
        new Response 
            .ErrorListener() { 
   
                    @Override
                    public void 
                    onErrorResponse(VolleyError error) { 
  
                        VolleyLog.d(TAG,  
                                    "Error: " 
                                        + error.getMessage()); 
                        hideProgressDialog(); 
                    } }) { 
  
          @Override
          public Priority getPriority() 
          { 
              return priority; 
          } 
  
      };