I'm trying to use Volley as a DBA layer to call a webservice that hadles JSON objects. Because this layer is below the activity and another service layer, it doesn't seem to be working properly. I'll try to explain my setup:
MainActivity:
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
ProductService productService = new ProductService();
productService.getProduct();
}
ProductService.java:
public void getProduct() {
JsonObjectRequest req = new JsonObjectRequest("http://echo.jsontest.com/name/Milk/price/1.23/", null, createMyReqSuccessListener(), createMyReqErrorListener());
ApplicationController.getInstance().addToRequestQueue(req);
}
private Response.Listener<JSONObject> createMyReqSuccessListener() {
return new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
Log.v("response", response.toString());
}
};
}
private Response.ErrorListener createMyReqErrorListener() {
return new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
return;
}
};
}
I hope that is clear enough.
In the end, I would like to use the ProductService::getProduct() from an activity and the the actual JSON response from the webservice in a variable which I can later use.
However, at the moment, the line
Log.v("response", response.toString());
doesn't even execute. What am I doing wrong?
What I would try is this:
Declare getProduct as
public void getProduct(Response.Listener<JSONObject> listener,
Response.ErrorListener errlsn) {
JsonObjectRequest req = new JsonObjectRequest("http://echo.jsontest.com/name/Milk/price/1.23/",null, listener, errlsn);
ApplicationController.getInstance().addToRequestQueue(req);
}
And than call in your activity like this:
productService.getProduct(
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
variableFromActivity = response;
//Or call a function from the activity, or whatever...
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
//Show error or whatever...
}
});
Create an abstract class AppActivity
import androidx.appcompat.app.AppCompatActivity;
public abstract class AppActivity extends AppCompatActivity
{
abstract void callback(String data);
}
Extend all your Activities using AppActivity
public class MainActivity extends AppActivity
{
#Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
String url = "Your URL";
JSONObject jsonBody = new JSONObject();
try {
jsonBody.put("Title", "Android Volley Demo");
jsonBody.put("Author", "BNK");
}
catch (JSONException e) {
System.out.println(e);
}
final String requestBody = jsonBody.toString();
Messenger messenger = new Messenger(MainActivity.this);
messenger.sendMessage(this, url, requestBody);
}
public void callback(String data)
{
System.out.println(data);
}
}
Create Messenger class as below:
public class Messenger
{
private AppActivity myActivity;
public Messenger(AppActivity activity)
{
myActivity = activity;
}
public void sendMessage(Context context, String url, final String requestBody)
{
// Instantiate the RequestQueue.
RequestQueue queue = Volley.newRequestQueue(context);
// Request a string response from the provided URL.
StringRequest stringRequest =
new StringRequest(
Request.Method.POST,
url,
null,
new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
System.out.println(error);
}
}
) {
#Override
public String getBodyContentType() {
return "application/json; charset=utf-8";
}
#Override
public byte[] getBody() throws AuthFailureError {
try {
return requestBody == null ? null : requestBody.getBytes("utf-8");
}
catch (UnsupportedEncodingException uee) {
VolleyLog.wtf("Unsupported Encoding while trying to get the bytes of %s using %s", requestBody, "utf-8");
return null;
}
}
#Override
protected Response<String> parseNetworkResponse(NetworkResponse response)
{
myActivity.callback(new String(response.data));
String responseString = "";
if (response != null) {
responseString = String.valueOf(response.statusCode);
// can get more details such as response.headers
}
return Response.success(responseString, HttpHeaderParser.parseCacheHeaders(response));
}
};
queue.add(stringRequest);
}
}
Hope it helps.
Related
I am trying to retrieve a JsonObject via GET request. When I set Breakpoints in my code I see that the count() method returns nothing. After that the onResponse method from the inner class gets called and the desired value gets retrieved.
I am calling the count() method inside the save() method. In order to create a JSONObject. The code creates the JSONObject before it retrieves the correct customer count.
I am using a custom requesQueue called AppController to queue the network request. I hope someone understands this strange behaviour.
#Override
public void save(Customer customer) throws JSONException {
int zw = count();
JSONObject obj = new JSONObject();
obj.put("customernumber", count + 1);
obj.put("name", customer.getName());
obj.put("lastname", customer.getLastname());
obj.put("phonenumber", customer.getPhonenumber());
obj.put("addressid", customer.getAdressID());
obj.put("password", customer.getPassword());
String urlJsonObj = URL;
JsonObjectRequest jsonObjReq = new JsonObjectRequest(Request.Method.POST,
urlJsonObj, obj,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
System.out.println(response);
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d("Error: " + error.getMessage());
}
});
AppController.getInstance().addToRequestQueue(jsonObjReq);
}
#Override
public int count() {
String countURL = URL + "/count";
JsonObjectRequest jsonObjReq = new JsonObjectRequest
(Request.Method.GET, countURL, null, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
// Parsing json object response
// response will be a json object
count = response.getInt("count");
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d( "Error: " + error.getMessage());
}
});
AppController.getInstance().addToRequestQueue(jsonObjReq);
return count;
The AppController network queue
public class AppController extends Application {
public static final String TAG = AppController.class
.getSimpleName();
private RequestQueue mRequestQueue;
private static AppController mInstance;
#Override
public void onCreate() {
super.onCreate();
mInstance = this;
}
public static synchronized AppController getInstance() {
return mInstance;
}
public RequestQueue getRequestQueue() {
if (mRequestQueue == null) {
mRequestQueue = Volley.newRequestQueue(getApplicationContext());
}
return mRequestQueue;
}
public <T> void addToRequestQueue(Request<T> req, String tag) {
// set the default tag if tag is empty
req.setTag(TextUtils.isEmpty(tag) ? TAG : tag);
getRequestQueue().add(req);
}
public <T> void addToRequestQueue(Request<T> req) {
req.setTag(TAG);
getRequestQueue().add(req);
}
public void cancelPendingRequests(Object tag) {
if (mRequestQueue != null) {
mRequestQueue.cancelAll(tag);
}
}
What's Happening?
This is happening due to incorrect thread usage. count() function performs the network request in the background thread, so it won't return the count immediately when we call it from save() function.
Solution
Wait for the response from count API and then perform a save operation. Replace the above implementation with the following
#Override
public void save(Customer customer) throws JSONException {
count();
}
private void performSave(Customer customer, int count) throws JSONException {
int zw = count; // Finally received the count
JSONObject obj = new JSONObject();
obj.put("customernumber", count + 1);
obj.put("name", customer.getName());
obj.put("lastname", customer.getLastname());
obj.put("phonenumber", customer.getPhonenumber());
obj.put("addressid", customer.getAdressID());
obj.put("password", customer.getPassword());
String urlJsonObj = URL;
JsonObjectRequest jsonObjReq = new JsonObjectRequest(Request.Method.POST,
urlJsonObj, obj,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
System.out.println(response);
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d("Error: " + error.getMessage());
}
});
AppController.getInstance().addToRequestQueue(jsonObjReq);
}
#Override
public int count(Customer customer) {
String countURL = URL + "/count";
JsonObjectRequest jsonObjReq = new JsonObjectRequest
(Request.Method.GET, countURL, null, new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
// Parsing json object response
// response will be a json object
count = response.getInt("count");
performSave(customer, count);
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
VolleyLog.d( "Error: " + error.getMessage());
}
});
AppController.getInstance().addToRequestQueue(jsonObjReq);
return 0; // Remove this return type as we will not use it anymore
}
I Want to Store the response of Volley in a Public variable but when I Toast it out the volley request that returns null
public JSONArray array ;
String URL = "http://192.168.1.104/json.php";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_json);
array = new JSONArray();
JsonArrayRequest request = new JsonArrayRequest( URL,new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
try {
array = response;
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
});
Volley.newRequestQueue(this).add(request);
Toast.makeText(json.this, array.toString(),Toast.LENGTH_LONG).show();
As people have said, calling the Toast initiation within onResponse() works, but the best way to handle this is to create a small listener interface or method that is called in onResponse and implemented where you need it.
I'd also strongly suggest only passing the data you need and saving that in a model class, rather than just saving the response outright.
a very simple example would be
String URL = "http://192.168.1.104/json.php";
// make sure your class implements this
public interface ResponseListener {
public gotResponse(JSONArray array);
}
// implementation of ResponseListener
public gotResponse(JSONArray array) {
// eventually do more with this data
Toast.makeText(json.this, array.toString(),Toast.LENGTH_LONG).show();
}
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_json);
ResponseListener listener = this;
JsonArrayRequest request = new JsonArrayRequest( URL,new Response.Listener<JSONArray>() {
#Override
public void onResponse(JSONArray response) {
try {
listener.gotResponse(response);
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
});
Volley.newRequestQueue(this).add(request);
One way could be moving the line:
Toast.makeText(json.this, array.toString(),Toast.LENGTH_LONG).show();
exactly to the line after: array = response;
public class BtcPaymentQR extends AppCompatActivity {
ImageView QrCode;
RequestQueue mQueue;
public static String btcAddress = "";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_btc_payment_qr);
QrCode = findViewById(R.id.imageViewQR);
mQueue = Volley.newRequestQueue(this);
getAddress();
Log.i("test", "onCreate: " + btcAddress);
}
public void getAddress(){
String url = "xxx"
JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, url, null,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
JSONObject jsonObject = response.getJSONObject("address");
String a = jsonObject.getString("extkey_next_receiving_address");
BtcPaymentQR.btcAddress=a;
Log.i("test", "onResponse: " + btcAddress);
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
}
});
mQueue.add(request);
}
Logcat
My Question is, How do I get the value of "a" from the method. I've tried everything to save it in another global variable, with return, with get and set.
I need the value to use it in a other Method
Your problem is solved by using static variable to save response,and static variables are part of class not object so you can use static variable with class name like MainActivity.myValue in my example.
Your Activity or Fragment Class:
MainActivity Extends AppCompatActivity{
public static String myValue="";
//define this in your classs where you run the web service
}
your response method
JsonObjectRequest request = new JsonObjectRequest(Request.Method.GET, url, null,
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
JSONObject jsonObject = response.getJSONObject("address");
String a = jsonObject.getString("extkey_next_receiving_address");
MainActivity.myValue=a;
Log.i("test", "onResponse: " + MainActivity.myValue);
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.i("test2", "onErrorResponse: error");
}
});
mQueue.add(request);
}
Simple way is using static variable. define a static variable for class and assign the value of 'a' to this static variable and use it every where.
I was looking for an easy way to make an HTTP post in Android with body, my api call should be like :
https:url/api/message?token=myToken&channel=Pew&text=someText&username=User
What I did is this, I created this class
Public class ApiCalls {
private static PostCommentResponseListener mPostCommentResponse;
private static Context mContext;
public ApiCalls(){
}
public static void postNewComment(Context context, final String message){
mContext = context;
String apiUrl = context.getResources().getString(R.string.api_url);
mPostCommentResponse.requestStarted();
RequestQueue queue = Volley.newRequestQueue(context);
StringRequest sr = new StringRequest(Request.Method.POST,apiUrl, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
mPostCommentResponse.requestCompleted();
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
mPostCommentResponse.requestEndedWithError(error);
}
}){
#Override
protected Map<String,String> getParams(){
Map<String,String> params = new HashMap<String, String>();
params.put("token",mContext.getResources().getString(R.string.access_token));
params.put("channel","pew");
params.put("text", message);
params.put("username","User");
return params;
}
#Override
public Map<String, String> getHeaders() throws AuthFailureError {
Map<String,String> params = new HashMap<String, String>();
params.put("Content-Type","application/x-www-form-urlencoded");
return params;
}
};
queue.add(sr);
}
public interface PostCommentResponseListener {
public void requestStarted();
public void requestCompleted();
public void requestEndedWithError(VolleyError error);
}
}
But it doesn't work, it only shows app has stopped.
Is good to use Volley? Or you recommend to me to use other way? I used to use HttpClient but it's deprecated now...
What I'm missing?
Log error
java.lang.NullPointerException: Attempt to invoke interface method 'void com.package.ApiCalls$PostCommentResponseListener.requestStarted()' on a null object reference
You can send json body using volly as below two ways.
1. Using JsonObjectRequest
Map<String,String> params = new HashMap<String, String>();
params.put("token",mContext.getResources().getString(R.string.access_token));
params.put("channel","pew");
params.put("text", message);
params.put("username","User");
JsonObjectRequest request_json = new JsonObjectRequest(URL, new JSONObject(params),
new Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
try {
//Process success response
} catch (JSONException e) {
e.printStackTrace();
}
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
// handle error
}
});
// add the request object to the queue to be executed
queue.add(request_json);
2. Using JSON directly in request body
JSONObject jsonBody = new JSONObject();
jsonBody.put("token",mContext.getResources().getString(R.string.access_token));
jsonBody.put("channel","pew");
jsonBody.put("text", message);
jsonBody.put("username","User");
final String mRequestBody = jsonBody.toString();
StringRequest sr = new StringRequest(Request.Method.POST,apiUrl, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
// Process success response
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
// handle error
}
}){
#Override
public String getBodyContentType() {
return "application/json; charset=utf-8";
}
#Override
public byte[] getBody() throws AuthFailureError {
try {
return mRequestBody.getBytes("utf-8");
} catch (Exception e) {
return null;
}
}
#Override
protected Response<String> parseNetworkResponse(NetworkResponse response) {
String responseString = "";
if (response != null) {
responseString = String.valueOf(response.statusCode);
}
return Response.success(responseString, HttpHeaderParser.parseCacheHeaders(response));
}
};
// add the request object to the queue to be executed
queue.add((sr);
Initialise your mPostCommentResponse like this:
public ApiCalls(){
mPostCommmentResponse = (PostCommentResponseListener)mContext;
}
it will do you work and rest is fine. Thanks.
EDITED:
In Another Activity from where you want to call "ApiCall" class, do code like that:
new ApiCalls().postNewComment(AnotherActivity.this,"Your Messsage here");
and in method "postNewComment" do like this:
mContext = context;
mPostCommmentResponse = (PostCommentResponseListener)mContext;
Is it ok and understable??
I have the following class which I want to change a bit so as to make it more "object oriented" and easy to read.
public class CreateLeague extends AppCompatActivity {
....
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
getSupportActionBar().setDisplayHomeAsUpEnabled(true);
setContentView(R.layout.activity_create_league);
createLeague(...);
}
public void createLeague(final String leagueName, final String username, final String password,final String start,final String end,final String openLeague) {
HttpsTrustManager.allowAllSSL();
String tag_json_obj = "json_obj_req";
final HashMap<String, String> postParams = new HashMap<String, String>();
postParams.put("league_name",leagueName);
postParams.put("username",username);
postParams.put("password",password);
postParams.put("league_start",start);
postParams.put("league_finish",end);
postParams.put("open_league",openLeague);
Response.Listener<JSONObject> listener;
Response.ErrorListener errorListener;
final JSONObject jsonObject = new JSONObject(postParams);
JsonObjectRequest jsonObjReq = new JsonObjectRequest(AppConfig.URL_CREATE_LEAGUE, jsonObject,
new com.android.volley.Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
Log.d("TAG", response.toString());
try {
if (response.getString("status").equals("success")){
Intent i = new Intent(CreateLeague.this, League.class);
startActivity(i);
finish();
}
} catch (JSONException e) {
Log.e("TAG", e.toString());
}
//pDialog.dismiss();
}
}, new com.android.volley.Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
//VolleyLog.d("TAG", "Error: " + error.getMessage());
//pDialog.dismiss();
}
}) {
#Override
public String getBodyContentType() {
return "application/json; charset=utf-8";
}
};
// Adding request to request queue
AppController.getInstance().addToRequestQueue(jsonObjReq, tag_json_obj);
}
}
In other words I want to create the createLeague(...) to another class i.e. CreateLeagueClass and instantiate that object inside the onCreate() method of the above class. So here is what I do.
public class CreateLeagueClass extends AppCompatActivity{
private void createLeague(final String leagueName, final String username, final String password,final String start,final String end,final String openLeague) {
HttpsTrustManager.allowAllSSL();
String tag_json_obj = "json_obj_req";
final HashMap<String, String> postParams = new HashMap<String, String>();
postParams.put("league_name",leagueName);
postParams.put("username",username);
postParams.put("password",password);
postParams.put("league_start",start);
postParams.put("league_finish",end);
postParams.put("open_league",openLeague);
Response.Listener<JSONObject> listener;
Response.ErrorListener errorListener;
final JSONObject jsonObject = new JSONObject(postParams);
JsonObjectRequest jsonObjReq = new JsonObjectRequest(AppConfig.URL_CREATE_LEAGUE, jsonObject,
new com.android.volley.Response.Listener<JSONObject>() {
#Override
public void onResponse(JSONObject response) {
Log.d("TAG", response.toString());
try {
if (response.getString("status").equals("success")){
Intent i = new Intent(CreateLeague.this, League.class);
startActivity(i);
finish();
}
} catch (JSONException e) {
Log.e("TAG", e.toString());
}
//pDialog.dismiss();
}
}, new com.android.volley.Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
//VolleyLog.d("TAG", "Error: " + error.getMessage());
//pDialog.dismiss();
}
}) {
#Override
public String getBodyContentType() {
return "application/json; charset=utf-8";
}
};
// Adding request to request queue
AppController.getInstance().addToRequestQueue(jsonObjReq, tag_json_obj);
}
}
The problem is that compiler is giving me an error in this line.
Intent i = new Intent(CreateLeague.this, League.class);
of the CreateLeagueClass
The error is like this.
app....CreateLeague is not an enclosing class
Any suggestions?
Thank you.
CreateLeague.this is the current instance of CreateLeague. It only works inside that class, When you move that code to another class, you have to pass that instance e.g. add a parameter CreateLeague cL to the Method createLeague and use CreateLeague.this when you call that method.