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Writing/Updating JSON to URL (www.myjson.com)

I'm using www.myjson.com as a storage for my json file which will be accessed/updated frequently.
I currently have this as my json file online:
https://api.myjson.com/bins/f5fr0
I'm planning to update it frequently using android studio, but I have no idea on how to do it. How can I write/update it so that I can change the values of my json using android/java code?

import android.util.Log;
import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.ProtocolException;
import java.net.URL;
public class HttpHandler {
private static final String TAG = HttpHandler.class.getSimpleName();
public HttpHandler() {
}
public String makeServiceCall(String reqUrl) {
String response = null;
try {
URL url = new URL(reqUrl);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setRequestMethod("GET");
// read the response
InputStream in = new BufferedInputStream(conn.getInputStream());
response = convertStreamToString(in);
} catch (MalformedURLException e) {
Log.e(TAG, "MalformedURLException: " + e.getMessage());
} catch (ProtocolException e) {
Log.e(TAG, "ProtocolException: " + e.getMessage());
} catch (IOException e) {
Log.e(TAG, "IOException: " + e.getMessage());
} catch (Exception e) {
Log.e(TAG, "Exception: " + e.getMessage());
}
return response;
}
private String convertStreamToString(InputStream is) {
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line;
try {
while ((line = reader.readLine()) != null) {
sb.append(line).append('\n');
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return sb.toString();
}
}
public class MainActivity extends AppCompatActivity {
private String TAG = MainActivity.class.getSimpleName();
ArrayList<HashMap<String, String>> contactList;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
new GetJSON().execute();
}
private class GetJSON extends AsyncTask<Void, Void, Void> {
#Override
protected void onPreExecute() {
super.onPreExecute();
Toast.makeText(MainActivity.this,"Json Data is
downloading",Toast.LENGTH_LONG).show();
}
#Override
protected Void doInBackground(Void... arg0) {
HttpHandler sh = new HttpHandler();
// Making a request to url and getting response
String url = "https://api.myjson.com/bins/f5fr0";
String jsonStr = sh.makeServiceCall(url);
Log.e(TAG, "Response from url: " + jsonStr);
if (jsonStr != null) {
try {
JSONObject jsonObj = new JSONObject(jsonStr);
// Getting JSON OBJECT node
JSONArray jsonObjInner = jsonObj.getJSONObject("channel");
String id = jsonObjInner.getString("id");
String name = jsonObjInner.getString("name");
String description = jsonObjInner.getString("description");
}
} catch (final JSONException e) {
Log.e(TAG, "Json parsing error: " + e.getMessage());
runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(getApplicationContext(),
"Json parsing error: " + e.getMessage(),
Toast.LENGTH_LONG).show();
}
});
}
} else {
Log.e(TAG, "Couldn't get json from server.");
runOnUiThread(new Runnable() {
#Override
public void run() {
Toast.makeText(getApplicationContext(),
"Couldn't get json from server. Check LogCat for possible errors!",
Toast.LENGTH_LONG).show();
}
});
}
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
}
}
}

Activity keeps restarting when I leave the activity and come back to it

I have two activities, When I will move from activity A to B, B keeps restarting or "refreshing", when i go back from B to A, it also keeps restarting. The code is very big, here I am posting area where I think problem causes :
Thread t = new Thread(new Runnable() {
#Override
public void run() {
while (true) {
deviceStatus();
try {
Thread.sleep(10000);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
}
});
t.start();
this is deviceStatus();
public void deviceStatus(){
try {
RequestQueue requestQueue = Volley.newRequestQueue(InActivate.this);
String URL = "http://gickuwait-dev.com/electionapi/api/DeviceStatus";
JSONObject jsonBody = new JSONObject();
jsonBody.put("device_PK", device_ID2);
final String requestBody = jsonBody.toString();
StringRequest stringRequest = new StringRequest(Request.Method.POST, URL, new Response.Listener<String>() {
#Override
public void onResponse(String response) {
if(response.equals("true")){
Intent intent = new Intent(InActivate.this, Vote.class);
startActivity(intent);
finish();
}else if(response.equals("false")) {
}
// Toast.makeText(getApplicationContext(), response.toString(), Toast.LENGTH_SHORT).show();
}
}, new Response.ErrorListener() {
#Override
public void onErrorResponse(VolleyError error) {
Log.e("VOLLEY", error.toString());
}
}) {
#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) {
String responseString;
String json = null;
try {
json = new String(response.data, HttpHeaderParser.parseCharset(response.headers));
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
responseString = String.valueOf(json).trim();
ArrayList<DeviceStatusResponse> list = new ArrayList<DeviceStatusResponse>();
Type listType = new TypeToken<List<DeviceStatusResponse>>() {}.getType();
list = new Gson().fromJson(responseString, listType);
device_Status = list.get(0).getIsActive().toString();
// Toast.makeText(getApplicationContext(), ""+device_Status+" null ", Toast.LENGTH_LONG).show();
return Response.success(device_Status, HttpHeaderParser.parseCacheHeaders(response));
}
};
requestQueue.add(stringRequest);
} catch (JSONException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
}
in Activity B, i have the same code to check the device status from the database, any help would be appreciated

You can use Handle to check the repeated task.
private Handler delayHandler = new Handler();
private Runnable runnable = new Runnable() {
#Override
public void run() {
deviceStatus();
driverDelayHandler.postDelayed(runnable, 1000);
}
};
Don't forgot to cancel on onStop method.
delayHandler.removeCallbacks(runnable);

NetworkOnMainThreadException but Using AsyncTask

I coded a class which starts a http connection for getting the text of e.g. website.
I used AsyncTask but I got NetworkOnMainException. May u help me?
The class
public class getXMLData extends AsyncTask<String, Void, String> {
TextView _textview;
public getXMLData(TextView textview) {
_textview = textview;
}
protected String doInBackground(String... url)
{
String _text = "";
try {
try {
URL _url = new URL(url[0]);
HttpURLConnection con = (HttpURLConnection) _url.openConnection();
_text = readStream(con.getInputStream());
}
catch (Exception e) {
e.printStackTrace();
}
}
catch (Exception e) {
e.printStackTrace();
}
return _text;
}
protected void onPostExecute(String result)
{
_textview.setText(result.toCharArray(), 0, result.length());
}
private String readStream(java.io.InputStream in) {
java.io.BufferedReader reader = null;
String result = "";
reader = new BufferedReader(new InputStreamReader(in));
try {
while ((reader.readLine() != null)) {
result = result + reader.readLine();
}
}
catch (java.io.IOException i)
{
}
finally
{
try {
reader.close();
}
catch (java.io.IOException e) {
e.printStackTrace();
}
}
return result;
}
Here how I start the AsyncTask:
bu_aktualize.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
_getXMLData.doInBackground("http://www.google.de");
}
});
Thanks for your help.

You do not call doInBackground() yourself. Instead, you call execute() or executeOnExecutor() to start the AsyncTask.
You may wish to review the documentation for AsyncTask, which shows an example of setting up an AsyncTask, including a call to execute().

Get value from Async task in Activity

I have a class as shown below. It is in a .java file called NQRequestHandler.java and I want to call this from an Activity.java. But I'm having problems with the AsyncTask method. When I run it in the Activity.java file it returns a null
value when I try to log the value of Globals.PUBLIC_KEY from the Activity.
Log.v("RESULT", "Public KEY JSON from OnStart" + Globals.PUBLIC_KEY);
public class NQRequestHandler {
private static NQRequestHandler instance;
public static final String TAG = NQRequestHandler.class.getSimpleName();
private Context mContext;
public NQRequestHandler(Context context) {
mContext = context;
}
public static synchronized NQRequestHandler getInstance(Context context) {
if (instance == null)
instance = new NQRequestHandler(context);
return instance;
}
public class requestHandler extends AsyncTask<String, Void, JSONArray> {
RequestListener requestListener;
public JSONArray requestResult;
public requestHandler() {
}
public void setRequestListener(RequestListener requestListener) {
this.requestListener = requestListener;
}
#Override
protected JSONArray doInBackground(String... params) {
try {
String url = "http://www.someurl.com";
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost(url);
List<NameValuePair> urlParameters = requestHandlerHelper(params);
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(urlParameters);
entity.setContentType(new BasicHeader(HTTP.CONTENT_TYPE, "application/x-www-form-urlencoded; charset=UTF-8"));
post.setEntity(entity);
HttpResponse response = client.execute(post);
System.out.println("Response Code : " + response.getStatusLine().getStatusCode());
Reader reader = new InputStreamReader(response.getEntity().getContent());
int contentLength = (int) response.getEntity().getContentLength();
Log.v(TAG, "Content Length DATA" + contentLength);
char[] charArray = new char[contentLength];
reader.read(charArray);
String responseData = new String(charArray);
JSONArray jsonResponse = new JSONArray(responseData);
return jsonResponse;
} catch (ClientProtocolException e) {
Log.i(TAG, "ClientProtocolException: ", e);
} catch (UnsupportedEncodingException e) {
Log.i(TAG, "UnsupportedEncodingException: ", e);
} catch (IOException e) {
Log.i(TAG, "IOException: ", e);
} catch (JSONException e) {
Log.i(TAG, "JSONException: ", e);
}
return null;
}
#Override
protected void onPostExecute(JSONArray results) {
if (results != null) {
requestListener.onRequestSuccess(results);
} else {
requestListener.onRequestFailed();
}
}
}
public interface RequestListener {
JSONArray onRequestSuccess(JSONArray data);
void onRequestFailed();
}
public void NQRequest(String... params) {
if (isNetworkAvailable()) {
requestHandler handler = new requestHandler();
RequestListener listener = new RequestListener() {
#SuppressWarnings("unchecked")
#Override
public JSONArray onRequestSuccess(JSONArray data) {
//TODO: Switch set data here
Log.v(TAG, "JSON FROM NQRequest" + data);
Globals.PUBLIC_KEY = String.valueOf(data);
return data;
}
#Override
public void onRequestFailed() {
Toast.makeText(mContext, "Network is unavailable. Request failed", Toast.LENGTH_LONG).show();
}
};
handler.setRequestListener(listener);
handler.execute(params);
} else {
Toast.makeText(mContext, "Network is unavailable", Toast.LENGTH_LONG).show();
}
}
private static List<NameValuePair> requestHandlerHelper(String... params) {
//Declare URL Parameter values
List<NameValuePair> urlParameters = new ArrayList<NameValuePair>();
String[] requestActionArray = Globals.REQUEST_ACTION_ID;
int actionSwitch = -1;
String[] requestActionHeaders = null;
//Find URL Parameter Action Switch
for (int i = 0; i < requestActionArray.length; i++) {
if (requestActionArray[i].equalsIgnoreCase(params[params.length - 1])) {
actionSwitch = i;
}
}
//Set Action Switch ID Parameters
requestActionHeaders = NQActionHeader(actionSwitch);
//Set URL Parameters
for (int i = 0; i < requestActionHeaders.length; i++) {
urlParameters.add(new BasicNameValuePair(requestActionHeaders[i], params[i]));
}
return urlParameters;
}
private boolean isNetworkAvailable() {
ConnectivityManager manager =
(ConnectivityManager) mContext.getSystemService(Context.CONNECTIVITY_SERVICE);
NetworkInfo networkInfo = manager.getActiveNetworkInfo();
return networkInfo != null && networkInfo.isConnected() ? true : false;
}
private static String[] NQActionHeader(int actionSwitch) {
/* some code goes here */
}
}
In the Activity class looks like this:
public class Application extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
try {
String message = "Hello World from Android";
Context mContext = getBaseContext();
NQRequestHandler.requestHandler handler = new NQRequestHandler.requestHandler();
NQRequestHandler requestHandler = NQRequestHandler.getInstance(mContext);
requestHandler.NQRequest(message, "sendPublicKey");
Log.v("RESULT", "Public KEY JSON from OnStart" + Globals.PUBLIC_KEY);
//Start Activity
Intent intent = new Intent(this, LoginActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(intent);
} catch (Exception e) {
e.printStackTrace();
}
}
}
The call to NQRequest in the Activity initiates the call to AsyncTask in the Activity. Any help with this? How do I implement a callback in the Activity.java to get method from OnRequestSuccess(); in the NQRequest()? Note: I'm trying to call the method in Activity.java in other multiple Activity.java files

i modified the structure for your reference.
Modified of requestHandler :-
//**** e.g.
class requestHandler extends AsyncTask<Object, Void, JSONArray> {
// define a caller
String requester;
Application caller;
YourEachActivityClass1 caller1;
//create a Constructor for caller;
public requestHandler (Application caller) {
// TODO Auto-generated constructor stub
this.caller = caller;
}
public requestHandler (YourEachActivityClass1 caller1) {
// TODO Auto-generated constructor stub
this.caller1 = caller1;
}
///&& method doInBackground
#Override
protected JSONArray doInBackground(Object... params) {
.....
//your process is here
//custom your returning jsonarray
try {
Context context = (Context) params[0];
Log.i(TAG, "context :"+context.getClass().getSimpleName());
requester = (Integer) params[1];
String message = (String) params[2];
String public= (String) params[3]
String url = "http://www.someurl.com";
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost(url);
List<NameValuePair> urlParameters = requestHandlerHelper(params);
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(urlParameters);
entity.setContentType(new BasicHeader(HTTP.CONTENT_TYPE, "application/x-www-form-urlencoded; charset=UTF-8"));
post.setEntity(entity);
HttpResponse response = client.execute(post);
System.out.println("Response Code : " + response.getStatusLine().getStatusCode());
Reader reader = new InputStreamReader(response.getEntity().getContent());
int contentLength = (int) response.getEntity().getContentLength();
Log.v(TAG, "Content Length DATA" + contentLength);
char[] charArray = new char[contentLength];
reader.read(charArray);
String responseData = new String(charArray);
JSONArray jsonResponse = new JSONArray(responseData);
Globals.PUBLIC_KEY = String.valueOf(jsonResponse);
return jsonResponse;
} catch (ClientProtocolException e) {
Log.i(TAG, "ClientProtocolException: ", e);
} catch (UnsupportedEncodingException e) {
Log.i(TAG, "UnsupportedEncodingException: ", e);
} catch (IOException e) {
Log.i(TAG, "IOException: ", e);
} catch (JSONException e) {
Log.i(TAG, "JSONException: ", e);
}
return null;
}
////&& return JSONArray back to ur activity class here by pass in caller
protected void onPostExecute(JSONArray jsonarray) {
if(requester.equals("IM_Application"))
caller.onBackgroundTaskCompleted(jsonarray);
else if(requester.equals("IM_ACTIVITY_1"))
caller1.onBackgroundTaskCompleted(jsonarray);
}
}
Application.class get ur json object:-
public class Application extends Activity {
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
try {
String message = "Hello World from Android";
new requestHandler(this).execute(getActivity(), "IM_Application", message, "sendPublicKey");
} catch (Exception e) {
e.printStackTrace();
}
}
//your returning result
public void onBackgroundTaskCompleted(JSONArray jsonarray) {
Log.i("TAG", jsonarray:"+jsonarray);
if(jsonarray!=null){
//process your jsonarray to get the Globals.PUBLIC_KEY)here
Log.v("onBackgroundTaskCompleted", "Public KEY JSON from OnStart" + Globals.PUBLIC_KEY);
//Start Activity
Intent intent = new Intent(this, LoginActivity.class);
intent.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TASK);
startActivity(intent);
}else{
Toast.makeText(mContext, "Network is unavailable. Request failed", Toast.LENGTH_LONG).show();
}
}
}
Gd Luck :)

The log from OnStart should return a null value for Globals.PUBLIC_KEY. You have just set an asynchronous task to run to set that value. It has not run yet by the time that log statement executes. You should receive the log input from the
Log.v(TAG, "JSON FROM NQRequest" + data);
call. That will mostly happen after your activity has finished onCreate, as it is an asynchronous call.

Fixed it works now.
public class HQHandler extends AsyncTask<String, Void, JSONArray> {
public static final String TAG = HQHandler.class.getSimpleName();
private static HQHandler instance;
RequestListener requestListener;
JSONArray requestResult;
Context mContext;
public HQHandler(Context context) {
this.mContext = context;
}
public static synchronized HQHandler getInstance(Context context) {
if (instance == null)
instance = new HQHandler(context);
return instance;
}
public void setRequestListener(RequestListener requestListener) {
this.requestListener = requestListener;
}
public JSONArray getRequestResult() {
return this.requestResult;
}
#Override
protected JSONArray doInBackground(String... params) {
try {
String url = "http://www.someurl.com";
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost(url);
List<NameValuePair> urlParameters = requestHandlerHelper(params);
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(urlParameters);
entity.setContentType(new BasicHeader(HTTP.CONTENT_TYPE, "application/x-www-form-urlencoded; charset=UTF-8"));
post.setEntity(entity);
HttpResponse response = client.execute(post);
System.out.println("Response Code : " + response.getStatusLine().getStatusCode());
Reader reader = new InputStreamReader(response.getEntity().getContent());
int contentLength = (int) response.getEntity().getContentLength();
Log.v(TAG, "Content Length DATA" + contentLength);
char[] charArray = new char[contentLength];
reader.read(charArray);
String responseData = new String(charArray);
JSONArray jsonResponse = new JSONArray(responseData);
return jsonResponse;
} catch (ClientProtocolException e) {
Log.i(TAG, "ClientProtocolException: ", e);
} catch (UnsupportedEncodingException e) {
Log.i(TAG, "UnsupportedEncodingException: ", e);
} catch (IOException e) {
Log.i(TAG, "IOException: ", e);
} catch (JSONException e) {
Log.i(TAG, "JSONException: ", e);
}
return null;
}
#Override
protected void onPostExecute(JSONArray results) {
if (results != null) {
requestListener.onRequestSuccess(results);
} else {
requestListener.onRequestFailed();
}
}
public interface RequestListener {
JSONArray onRequestSuccess(JSONArray data);
void onRequestFailed();
}
public JSONArray HQRequest(String... params) throws ExecutionException, InterruptedException, JSONException {
JSONArray result;
if (!isNetworkAvailable()) {
Toast.makeText(mContext, "Network is unavailable", Toast.LENGTH_LONG).show();
return null;
}
HQHandler handler = new HQHandler(this.mContext);
RequestListener listen = new RequestListener() {
#SuppressWarnings("unchecked")
#Override
public JSONArray onRequestSuccess(JSONArray data) {
return data;
}
#Override
public void onRequestFailed() {
Toast.makeText(mContext, "Network is unavailable. Request failed", Toast.LENGTH_LONG).show();
}
};
handler.setRequestListener(listen);
result = this.requestResult = handler.execute(params).get();
return result;
}
}

cannot print the value taken from socket connection

public class MyClientTask extends AsyncTask<String, String, String> {
String dstAddress;
int dstPort;
MyClientTask(String addr, int port) {
dstAddress = addr;
dstPort = port;
}
protected String doInBackground(String... arg0) {
String response = "";
Socket socket = null;
try {
socket = new Socket(dstAddress, dstPort);
BufferedReader stdIn = new BufferedReader(new InputStreamReader(socket.getInputStream()));
while ((response = stdIn.readLine()) != null) {
Log.i("response", response);
publishProgress(response);
}
Log.i("response", response);
} catch (UnknownHostException e) {
e.printStackTrace();
response = "UnknownHostException: " + e.toString();
} catch (IOException e) {
e.printStackTrace();
response = "IOException: " + e.toString();
} catch (Exception e) {
e.printStackTrace();
}
return response;
}
protected void onProgressUpdate(String... values) {
Log.i("prama", values[0]);
super.onProgressUpdate(values);
}
#Override
protected void onPostExecute(String result) {
Toast.makeText(MainActivity.this, result, Toast.LENGTH_LONG).show();
super.onPostExecute(result);
}
}
I write above code to read value from socket.when i start the async task the value will be print on the log as i do in doInbackground but my toast message will not be fired after the async task finished.