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Asynctask return null in SDK 23 and below device

I'm using Asynctask to pass the parameters of API. The Asynctask executing but the String Response in Asynctask PostExecute giving me a null for a device with SDK 23 and below. But when the device is equal or higher to SDK24(Nougat), it works perfectly and the data are being sent to the API however when the SDK is 23 and lower data are not being sent to API. Does anyone encounter this problem? Please enlighten me what I miss in my code or I do wrong code. Massive thank you.
private class sendToServerOfficial extends AsyncTask<String,Void,String> {
int statusCodeone;
String convert_txt_et_username = et_username.getText().toString();
String convert_txt_content = et_content.getText().toString();
#Override
protected String doInBackground(String... strings) {
try {
urlURL = new URL("http://www.testingsite.com/api/sendServer?/ip="+getIPAddress+"&phone_num="+getMobilePhoneNumber+"&user_text="+convert_txt_et_username+"&content_text="+convert_txt_content);
HttpURLConnection httpURLConnection = (HttpURLConnection) urlURL.openConnection();
httpURLConnection.setRequestMethod("POST");
httpURLConnection.setRequestProperty("Content-Type","UTF-8");
httpURLConnection.connect();
statusCodeone = httpURLConnection.getResponseCode();
if (statusCodeone == 200) {
InputStream it = new BufferedInputStream(httpURLConnection.getInputStream());
InputStreamReader read = new InputStreamReader(it);
BufferedReader buff = new BufferedReader(read);
StringBuilder dta = new StringBuilder();
String chunks;
while ((chunks = buff.readLine()) != null) {
dta.append(chunks);
}
buff.close();
read.close();
return dta.toString();
}
}
catch (ProtocolException e) { e.printStackTrace(); }
catch (MalformedURLException e) { e.printStackTrace(); }
catch (IOException e) { e.printStackTrace(); }
return null;
}
#Override
protected void onPostExecute(String response) {
Toast.makeText(MainActivity.this, response + "Form is submitted already" + urlURL, Toast.LENGTH_LONG).show();
txt_inputURL.setEnabled(true);
btnClick.setClickable(true);
txt_inputURL.getText().clear();
}
}

Can Java's FutureTask be an alternative to AsyncTask?

The docs say AsyncTask is designed to handle short operations(few seconds maximum) and states that Java classes like FutureTask are better for operations that last long. So I tried to send my location updates to the server using FutureTask but I am getting NetworkOnMainThreadException. I don't want to use AsyncTask because I wanted to keep the http connection open until the updates are cancelled. Here is my code:
SendLocation updates = new SendLocation(idt, String.valueOf(location.getLatitude()), String.valueOf(location.getLongitude()));
FutureTask ft = new FutureTask<String>(updates);
boolean b = ft.cancel(false);
ft.run();
class SendLocation implements Callable<String> {
String t, la, lo;
public SendLocation(String a, String b, String c){
this.t = a;
this.la = b;
this.lo = c;
}
public String call() {
sendUpdates(token, la, lo);
return "Task Done";
}
public void sendUpdates(String a, String b, String c){
HttpURLConnection urlConn = null;
try {
try {
URL url;
//HttpURLConnection urlConn;
url = new URL(remote + "driver.php");
urlConn = (HttpURLConnection) url.openConnection();
System.setProperty("http.keepAlive", "true");
//urlConn.setDoInput(true); //this is for get request
urlConn.setDoOutput(true);
urlConn.setUseCaches(false);
urlConn.setRequestProperty("Content-Type", "application/json");
urlConn.setRequestProperty("Accept", "application/json");
urlConn.setRequestMethod("POST");
urlConn.connect();
try {
//Create JSONObject here
JSONObject json = new JSONObject();
json.put("drt", a);
json.put("drlat", b);
json.put("drlon", c);
String postData = json.toString();
// Send POST output.
OutputStreamWriter os = new OutputStreamWriter(urlConn.getOutputStream(), "UTF-8");
os.write(postData);
Log.i("NOTIFICATION", "Data Sent");
os.flush();
os.close();
BufferedReader reader = new BufferedReader(new InputStreamReader(urlConn.getInputStream()));
String msg = "";
String line = "";
while ((line = reader.readLine()) != null) {
msg += line;
}
Log.i("msg=", "" + msg);
} catch (JSONException jsonex) {
jsonex.printStackTrace();
Log.e("jsnExce", jsonex.toString());
}
} catch (MalformedURLException muex) {
// TODO Auto-generated catch block
muex.printStackTrace();
} catch (IOException ioex) {
ioex.printStackTrace();
try { //if there is IOException clean the connection and clear it for reuse(works if the stream is not too long)
int respCode = urlConn.getResponseCode();
InputStream es = urlConn.getErrorStream();
byte[] buffer = null;
int ret = 0;
// read the response body
while ((ret = es.read(buffer)) > 0) {
Log.e("streamingError", String.valueOf(respCode) + String.valueOf(ret));
}
// close the errorstream
es.close();
} catch(IOException ex) {
// deal with the exception
ex.printStackTrace();
}
}
} catch (Exception e) {
e.printStackTrace();
Log.e("ERROR", "There is error in this code " + String.valueOf(e));
}
}
}
Doesn't it get executed in a worker thread? If the answer is no why does the docs say that it is an alternative to AsyncTask?

Your code must not be in the void run() method. This is where the asynchronous code is ran.

HttpUrlConnection does not work on mobile device but on emulator

all of a sudden my mobile device can't connect to the local server anymore. async tasks are not executed and i just can't figure out why. slowly i'm getting really desperate because in my opinion i didn't change anything to cause this.
as an example, this is a background task which is not working
public class Login extends AsyncTask<String, Void, String>{
private String loginUrl = "http://...";
private int loginSuccess = 0;
public String getToken(String fromJson) throws JSONException {
JSONObject json = new JSONObject(fromJson);
if(json.has("api_authtoken")) {
loginSuccess = 1;
String appToken = json.getString("api_authtoken");
return appToken;
}
else {
return json.toString();
}
}
public String doInBackground(String... arg0) {
// so that they can be closed in the finally block.
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
String authToken;
try {
// get logged in to get the api_authtoken
String email = (String) arg0[0];
String password = (String) arg0[1];
URL url = new URL(loginUrl);
// Create the request and open the connection
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("POST");
urlConnection.setRequestProperty("Content-Type", "application/json");
urlConnection.setRequestProperty("Accept", "application/json");
//put values of edittexts into json-Object
JSONObject data = new JSONObject();
try {
data.put("email", email);
data.put("password", password);
} catch(JSONException e) {
Log.e("EXCEPTION", "unexpected JSON exception", e);
e.printStackTrace();
}
urlConnection.connect();
OutputStreamWriter wr = new OutputStreamWriter(urlConnection.getOutputStream());
wr.write(data.toString());
wr.flush();
reader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
StringBuilder sb = new StringBuilder();
String line = null;
//read server response
while((line = reader.readLine()) != null) {
sb.append(line);
}
//receive server "answer"
try {
return getToken(sb.toString());
}catch(JSONException e) {
Log.e("LOG", "unexpected JSON exception", e);
e.printStackTrace();
} finally{
if (urlConnection != null) {
urlConnection.disconnect();
}
if (reader != null) {
try {
reader.close();
} catch (final IOException e) {
Log.e("MainActivity", "Error closing stream", e);
}
}
}
//return sb.toString();
return null;
}
catch(IOException e) {
Log.e("LoginTask", "Error ", e);
// If the code didn't successfully get the data, there's no point in attempting
// to parse it.
//forecastJsonStr = null;
return null;
}
}
public void onPostExecute(String result) {
super.onPostExecute(result);
//Log.v("RESULT", result);
if(result == null) {
CharSequence text = "no internet connection";
int duration = Toast.LENGTH_LONG;
Toast toast = Toast.makeText(MainActivity.this, text, duration);
toast.setGravity(Gravity.CENTER_VERTICAL, 0, 0);
toast.show();
}
if(loginSuccess == 0) {
// if the request wasn't successful
// give user a message via toast
CharSequence text = "wrong password or user. please try again";
int duration = Toast.LENGTH_LONG;
Toast toast = Toast.makeText(MainActivity.this, text, duration);
toast.setGravity(Gravity.CENTER_VERTICAL, 0, 0);
toast.show();
}
else {
// save token in shared preferences
SharedPreferences tokenPref = getSharedPreferences(getString(R.string.preference_token), Context.MODE_PRIVATE);
SharedPreferences.Editor editorToken = tokenPref.edit();
editorToken.putString(getString(R.string.saved_auth_token), result);
editorToken.commit();
//save login status = 1 in shared preferences
SharedPreferences loginPref = getSharedPreferences(getString(R.string.preference_logged_in), Context.MODE_PRIVATE);
SharedPreferences.Editor editorLogin = loginPref.edit();
editorLogin.putString(getString(R.string.saved_login), "1");
editorLogin.commit();
Intent mapsIntent = new Intent(getApplicationContext(), MapsActivity.class);
startActivity(mapsIntent);
}
}
}

HttpClient is not supported any more in sdk 23. You have to use URLConnection or downgrade to sdk 22 (compile 'com.android.support:appcompat-v7:22.2.0')
If you need sdk 23, add this to your gradle:
android {
useLibrary 'org.apache.http.legacy'
}
HttpClient won't import in Android Studio

You should think about using a HTTP library, there is a bunch of them on internet, some are really easy to use, optimize and errorless.
For example, Volley (made by Google, I really like this one), okHttp or Picasso (for image).
You should take a look at this.

If you want to send (output), for example with POST or PUT requests you need to use this :-
urlConnection.setDoOutput(true);
In your code :-
public class Login extends AsyncTask<String, Void, String>{
private String loginUrl = "http://...";
private int loginSuccess = 0;
public String getToken(String fromJson) throws JSONException {
JSONObject json = new JSONObject(fromJson);
if(json.has("api_authtoken")) {
loginSuccess = 1;
String appToken = json.getString("api_authtoken");
return appToken;
}
else {
return json.toString();
}
}
public String doInBackground(String... arg0) {
// so that they can be closed in the finally block.
HttpURLConnection urlConnection = null;
BufferedReader reader = null;
String authToken;
try {
// get logged in to get the api_authtoken
String email = (String) arg0[0];
String password = (String) arg0[1];
URL url = new URL(loginUrl);
// Create the request and open the connection
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("POST");
urlConnection.setRequestProperty("Content-Type", "application/json");
urlConnection.setRequestProperty("Accept", "application/json");
urlConnection.setDoOutput(true); // HERE
//put values of edittexts into json-Object
JSONObject data = new JSONObject();
try {
data.put("email", email);
data.put("password", password);
} catch(JSONException e) {
Log.e("EXCEPTION", "unexpected JSON exception", e);
e.printStackTrace();
}
OutputStreamWriter wr = new OutputStreamWriter(urlConnection.getOutputStream());
wr.write(data.toString());
wr.flush();
urlConnection.connect();
reader = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
StringBuilder sb = new StringBuilder();
String line = null;
//read server response
while((line = reader.readLine()) != null) {
sb.append(line);
}
//receive server "answer"
try {
return getToken(sb.toString());
}catch(JSONException e) {
Log.e("LOG", "unexpected JSON exception", e);
e.printStackTrace();
} finally{
if (urlConnection != null) {
urlConnection.disconnect();
}
if (reader != null) {
try {
reader.close();
} catch (final IOException e) {
Log.e("MainActivity", "Error closing stream", e);
}
}
}
//return sb.toString();
return null;
}
catch(IOException e) {
Log.e("LoginTask", "Error ", e);
// If the code didn't successfully get the data, there's no point in attempting
// to parse it.
//forecastJsonStr = null;
return null;
}
}
public void onPostExecute(String result) {
super.onPostExecute(result);
//Log.v("RESULT", result);
if(result == null) {
CharSequence text = "no internet connection";
int duration = Toast.LENGTH_LONG;
Toast toast = Toast.makeText(MainActivity.this, text, duration);
toast.setGravity(Gravity.CENTER_VERTICAL, 0, 0);
toast.show();
}
if(loginSuccess == 0) {
// if the request wasn't successful
// give user a message via toast
CharSequence text = "wrong password or user. please try again";
int duration = Toast.LENGTH_LONG;
Toast toast = Toast.makeText(MainActivity.this, text, duration);
toast.setGravity(Gravity.CENTER_VERTICAL, 0, 0);
toast.show();
}
else {
// save token in shared preferences
SharedPreferences tokenPref = getSharedPreferences(getString(R.string.preference_token), Context.MODE_PRIVATE);
SharedPreferences.Editor editorToken = tokenPref.edit();
editorToken.putString(getString(R.string.saved_auth_token), result);
editorToken.commit();
//save login status = 1 in shared preferences
SharedPreferences loginPref = getSharedPreferences(getString(R.string.preference_logged_in), Context.MODE_PRIVATE);
SharedPreferences.Editor editorLogin = loginPref.edit();
editorLogin.putString(getString(R.string.saved_login), "1");
editorLogin.commit();
Intent mapsIntent = new Intent(getApplicationContext(), MapsActivity.class);
startActivity(mapsIntent);
}
}
}

Android: java.net.protocolException does not support output

I was previously using HttpClient and BasicNameValuePairs, for some reason i have to shift to HttpUrlConnection.
Hence this code, to make a HttpPost request with certain parameters:
public class MConnections {
static String BaseURL = "http://www.xxxxxxxxx.com";
static String charset = "UTF-8";
private static String result;
private static StringBuilder sb;
private static List<String> cookies = new ArrayList<String>();
public static String PostData(String url, String sa[][]) {
HttpURLConnection connection = null;
try {
connection = (HttpURLConnection) new URL(BaseURL + url)
.openConnection();
} catch (MalformedURLException e1) {
} catch (IOException e1) {
}
cookies = connection.getHeaderFields().get("Set-Cookie");
try{
connection.setDoOutput(true); // Triggers POST.
connection.setRequestProperty("Accept-Charset", charset);
connection.setRequestProperty("Content-Type",
"application/x-www-form-urlencoded;charset=" + charset);
}catch (Exception e) {
//Here i get Exception that "java.lang.IllegalStateException: Already connected"
}
OutputStream output = null;
String query = "";
int n = sa.length;
for (int i = 0; i < n; i++) {
try {
query = query + sa[i][0] + "="
+ URLEncoder.encode(sa[i][1], "UTF-8");
} catch (UnsupportedEncodingException e) {
}
}
try {
output = connection.getOutputStream();
output.write(query.getBytes(charset));
} catch (Exception e) {
//Here i get Exception that "android: java.net.protocolException: Does not support output"
} finally {
if (output != null)
try {
output.close();
} catch (IOException e) {
}
}
InputStream response = null;
try {
response = connection.getInputStream();
} catch (IOException e) {
//Here i get Exception that "java.io.IOException: BufferedInputStream is closed"
} finally {
//But i am closing it here
connection.disconnect();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
response, "iso-8859-1"), 8);
sb = new StringBuilder();
sb.append(reader.readLine());
String line = "0";
while ((line = reader.readLine()) != null) {
sb.append("\n" + line);
}
response.close();
result = sb.toString();
} catch (Exception e) {
}
return result;
}
}
But i get such Exceptions as commented in the code.
Actually i am calling MConnections.PostData() twice from my Activity using a AsyncTask. This might cause the Exception: Already Connected but i am using connection.disconnect. But why am i still getting that Exception?
Am i using it the wrong way?
Thank You

For the protocol exception, try adding the following before you call getOutputStream():
connection.setDoOutput(true);
Discovered this answer thanks to Brian Roach's answer here: https://stackoverflow.com/a/14026377/387781
Side note: I was having this issue on my HTC Thunderbolt running Gingerbread, but not on my Nexus 4 running Jelly Bean.

Why does Android not send my second SSL request?

My Android app is talking to a webserver using SSL and GET requests. After switching to API 10 (Gingerbread) the SSL connection works - but only for the first time after the app starts...
The first request is sent by the main activity - after getting a response, another activity starts and sends multiple requests. And none of them is answered. In both cases the request is sent using a litte WebService class that is initiated in a new AsyncTask. After downsizing this alass, the only thing it actually contains is the URL(-String). Each activity starts its own instance of this class.
Here is the method that should do the GET request. As easily visible I included some code to avoid keep-alive - not that I don't like it, but it has been suggested in other answers to do so to avoid problems with multiple connections. Well, it did not work in my case.
public String webGet(String methodName, Map<String, String> params) {
String getUrl = webServiceUrl + methodName;
index++;
final int connectionID = index;
int i = 0;
for (Map.Entry<String, String> param : params.entrySet()) {
if (i == 0) {
getUrl += "?";
} else {
getUrl += "&";
}
try {
getUrl += param.getKey() + "=" + URLEncoder.encode(param.getValue(), "UTF-8");
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}
i++;
}
String response;
Log.e("WebGetURL", "["+connectionID+"] " + getUrl);
URL url;
try {
url = new URL(getUrl);
} catch (MalformedURLException e) {
Log.e("WebService", "Malformed URL: " + getUrl);
return null;
}
HttpURLConnection urlConnection;
try {
Log.e("WebGetResponse", "["+connectionID+"] openConnection()");
System.setProperty("http.keepAlive", "false");
if (webServiceSsl) {
Log.e("WebService", "Using HTTPS");
urlConnection = (HttpsURLConnection) url.openConnection();
} else {
urlConnection = (HttpURLConnection) url.openConnection();
}
urlConnection.setUseCaches(false);
urlConnection.setRequestProperty("Connection","Keep-Alive");
urlConnection.setDoOutput(false);
urlConnection.setDoInput(true);
urlConnection.setRequestMethod("GET");
} catch (IOException e) {
Log.e("WebService", "I/O exception opening connection: " + e.getMessage());
e.printStackTrace();
return null;
}
urlConnection.setConnectTimeout(5000);
urlConnection.setReadTimeout(10000);
urlConnection.setRequestProperty("Connection", "close");
try {
urlConnection.connect();
Log.e("WebGetResponse", "["+connectionID+"] getInputStream()");
// This is the last thing I hear from my thread
BufferedInputStream bin = new BufferedInputStream(urlConnection.getInputStream());
Log.e("WebGetResponse", "["+connectionID+"] gotInputStream()");
byte[] contents = new byte[1024];
int bytesRead=0;
StringBuilder strFileContents = new StringBuilder();
Log.e("WebGetResponse", "["+connectionID+"] Waiting for data");
while((bytesRead = bin.read(contents)) != -1) {
String add = new String(contents, 0, bytesRead);
strFileContents.append(add);
}
bin.close();
response = strFileContents.toString();
} catch (IOException e) {
Log.e("WebService", "I/O exception reading stream: " + e.getMessage());
e.printStackTrace();
return null;
} finally {
urlConnection.disconnect();
}
Log.e("WebGetResponse", "["+connectionID+"] " + response);
return response;
}
I have been trying ans searching - I don't get the problem. Actually I cannot test the class on a non-https server currently, so I am unaware if the problem occurs in HTTP as well. However, the handshake seems to work, because the first request works well.
And here is the code that should start the request (final param is the GET content to send):
class ServerDataThread extends AsyncTask<Integer, Integer, String[]> {
#Override
protected String[] doInBackground(Integer... attempts) {
sendActive++;
int count = attempts.length;
String[] responses = new String[count];
for (int i = 0; i < count; i++) {
responses[i] = server.webGet("collector.php", params);
}
return responses;
}
protected void onPostExecute(String[] responses) {
sendActive--;
for (int i = 0; i < responses.length; i++) {
if (responses[i] == null) {
continue;
}
onResponseData(responses[i]);
}
}
}
new ServerDataThread().execute(0);
Could anyone please help me out with a hint what I am doing wrong? Thank you very much!
BurninLeo