How do you use the Android Volley API?

Edit: finally here it is an official training about "Volley library"

I found some examples about Volley library

• 6 examples by Ognyan Bankov :

  • Simple request
  • JSON request
  • Gson request
  • Image loading
  • with newer external HttpClient (4.2.3)
  • With Self-Signed SSL Certificate.

• one good simple example by Paresh Mayani

• other example by HARDIK TRIVEDI

• (NEW) Android working with Volley Library by Ravi Tamada

Hope this helps you

Unfortunately there is no documentation for a Volley library like JavaDocs until now. Only repo on github and several tutorials across the Internet. So the only good docs is source code :) . When I played with Volley I read this tutorial.

About post/get you can read this : Volley - POST/GET parameters

Hope this helps

This is an illustration for making a POST request using Volley. StringRequest is used to get response in the form of String.
Assuming your rest API returns a JSON. The JSON response from your API is received as String here, which you can covert again to JSON and process it further. Added comments in code.

StringRequest postRequest = new StringRequest(Request.Method.POST, "PUT_YOUR_REST_API_URL_HERE",            new Response.Listener<String>() {                @Override                public void onResponse(String response) {                    try {                        final JSONObject jsonObject = new JSONObject(response);                        // Process your json here as required                    } catch (JSONException e) {                        // Handle json exception as needed                    }                }            },            new Response.ErrorListener() {                @Override                public void onErrorResponse(VolleyError error) {                    String json = null;                    NetworkResponse response = error.networkResponse;                    if(response != null && response.data != null){                        switch(response.statusCode) {                            default:                                String value = null;                                try {                                    // It is important to put UTF-8 to receive proper data else you will get byte[] parsing error.                                    value = new String(response.data, "UTF-8");                                } catch (UnsupportedEncodingException e) {                                    e.printStackTrace();                                }                                json = trimMessage(value, "message");                                // Use it for displaying error message to user                                 break;                        }                    }                    loginError(json);                    progressDialog.dismiss();                    error.printStackTrace();                }                  public String trimMessage(String json, String key){                    String trimmedString = null;                    try{                        JSONObject obj = new JSONObject(json);                        trimmedString = obj.getString(key);                    } catch(JSONException e){                        e.printStackTrace();                        return null;                    }                    return trimmedString;                }            }    ) {        @Override        protected Map<String, String> getParams() {            Map<String, String> params = new HashMap<>();            params.put("abc", "pass abc");            params.put("xyz", "pass xyz");            // Pass more params as needed in your rest API    // Example you may want to pass user input from EditText as a parameter    // editText.getText().toString().trim()            return params;        }          @Override        public String getBodyContentType() {            // This is where you specify the content type            return "application/x-www-form-urlencoded; charset=UTF-8";        }    };    // This adds the request to the request queue    MySingleton.getInstance(YourActivity.this).addToRequestQueue(postRequest);

// Below is MySingleton class

public class MySingleton {    private static MySingleton mInstance;    private RequestQueue mRequestQueue;    private static Context mCtx;      private MySingleton(Context context) {        mCtx = context;        mRequestQueue = getRequestQueue();    }    public static synchronized MySingleton getInstance(Context context) {        if (mInstance == null) {            mInstance = new MySingleton(context);        }        return mInstance;    }    public RequestQueue getRequestQueue() {        if (mRequestQueue == null) {            // getApplicationContext() is key, it keeps you from leaking the            // Activity or BroadcastReceiver if someone passes one in.            mRequestQueue = Volley.newRequestQueue(mCtx.getApplicationContext());        }        return mRequestQueue;    }    public <T> void addToRequestQueue(Request<T> req) {        getRequestQueue().add(req);    }}