Develop Reference

Parse Json data into a Json object

I have a problem with parsing a tag inside a Json object.
My json code is structured like that:
{"giocatori":[{"nome":"Giovanni","cognome":"Muchacha","numero":"1","ruolo":"F-G"},
{"nome":"Giorgio","cognome":"Rossi","numero":"2","ruolo":"AG"},
{"nome":"Andrea","cognome":"Suagoloso","numero":"3","ruolo":"P"},
{"nome":"Salvatore","cognome":"Aranzulla","numero":"4","ruolo":"G"},
{"nome":"Giulio","cognome":"Muchacha","numero":"5","ruolo":"F"}]}
I got the code that let me get the Json file from here: Get JSON Data from URL Using Android? and I'm trying to parse a tag (for example the "nome" tag) into a Json object.
This is the code I got:
public class MainActivity extends AppCompatActivity {
Button btnHit;
TextView txtJson;
ProgressDialog pd;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
btnHit = (Button) findViewById(R.id.btnHit);
txtJson = (TextView) findViewById(R.id.tvJsonItem);
btnHit.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
new JsonTask().execute("https://api.myjson.com/bins/177dpo");
}
});
}
private class JsonTask extends AsyncTask<String, String, String> {
protected void onPreExecute() {
super.onPreExecute();
pd = new ProgressDialog(MainActivity.this);
pd.setMessage("Please wait");
pd.setCancelable(false);
pd.show();
}
protected String doInBackground(String... params) {
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
URL url = new URL(params[0]);
connection = (HttpURLConnection) url.openConnection();
connection.connect();
InputStream stream = connection.getInputStream();
reader = new BufferedReader(new InputStreamReader(stream));
StringBuffer buffer = new StringBuffer();
String line = "";
while ((line = reader.readLine()) != null) {
buffer.append(line+"\n");
Log.d("Response: ", "> " + line);
}
return buffer.toString();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (connection != null) {
connection.disconnect();
}
try {
if (reader != null) {
reader.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
if (pd.isShowing()){
pd.dismiss();
}
txtJson.setText(result);
}
}
}
I've never worked with this type of file so I'll really appreciate your help!

You can use something like this:
try {
String servResponse = response.toString();
JSONObject parentObj = new JSONObject(servResponse);
JSONArray parentArray = parentObj.getJSONArray("giocatori");
if (parentArray.length() == 0) {
//if it's empty, do something (or not)
} else {
//Here, finalObj will have your jsonObject
JSONObject finalObj = parentArray.getJSONObject(0);
//if you decide to store some value of the object, you can do like this (i've created a nomeGiocatori for example)
nomeGiocatori = finalObj.getString("nome");
}
} catch (Exception e) {
Log.d("Exception: ", "UnknownException");
}
I use this kind of code all the time, works like a charm.

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();
}
}

Screen freezes when downloading content from server in android

I am downloading JSON Content from server in the MainActivity and passing the JSON from MainActivity to ListActivity, the problem here is I have added a sleep time of 10s in the backend server i.e. Php from where the data is fetched. Since, the response will the delayed I would expect that screen opens and waits until the response comes and move to next screen.
But what is happening is the screen goes white/black completely untill the response is recieved and ListActivity is loaded, the problem here is the MainActivity is never visible. Below is code for the same:
MainActivity
JSONData jsonData = new JSONData();
String jsonList = jsonData.fetchList();
Intent intent = new Intent(getApplicationContext(),ListActivity.class);
intent.putExtra("jsonList",jsonList);
startActivity(intent);
finish();
JSON Data class
public String fetchList() {
try {
String list = new DownloadJSONData().execute(listURL).get().toString();
return list;
} catch (Exception e) {
return "";
}
}
private class DownloadJSONData extends AsyncTask<String, String, String> {
protected void onPreExecute() {
super.onPreExecute();
}
protected String doInBackground(String... params) {
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
URL url = new URL(params[0]);
connection = (HttpURLConnection) url.openConnection();
connection.connect();
InputStream stream = connection.getInputStream();
reader = new BufferedReader(new InputStreamReader(stream));
StringBuffer buffer = new StringBuffer();
String line;
while ((line = reader.readLine()) != null) {
buffer.append(line + "\n");
}
return buffer.toString();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (connection != null) {
connection.disconnect();
}
try {
if (reader != null) {
reader.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return "";
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
}
}

you are using get() method which accquires the main thread or ui thread untill the async task is completed
you should avoid using get() and also can use progress dialog in onPreExecute for displaying progression on network call to user

Informationparsing from URL-Request not working / Didn't found TextView

i need your help. I want to send a URL Request, get response and create a JSON Object. My first try was totally wrong. Now I found a tutorial and made a new try.
My Activity looks like:
public class Patienten extends Activity {
//Beacon Elemente
private String UUID;
private String Major;
private String Minor;
private TextView output;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_patienten);
output = (TextView) findViewById(R.id.output);
UpdateBeaconInformation();
Button cmdHit = (Button) findViewById(R.id.cmd_hit);
cmdHit.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
new JSONTask().execute("//http://kusber-web.de/JsonTest.txt");
}
});
setTitle(Surname + ", " + FirstName);
// output.setText(output.getText().toString() + "Gefundener Patient:\n" + "Name: " + Surname + ", " + FirstName + "\nGeb.-Dat: " + Birthdate);
}
Then I created a new Java Class and built an asyncTask with it. But I can't access to the textview output in onPostExecute to update it.
public class JSONTask extends AsyncTask<String, String, String> {
#Override
protected String doInBackground(String... urls) {
HttpURLConnection connection = null;
BufferedReader reader = null;
try {
//http://kusber-web.de/JsonTest.txt
//http://nilsbenning.selfhost.me/PatientFinder.php?beacon_comID=5181f8a3-7354-46ac-b22d-952ec395ab06&beacon_major=12&beacon_minor=249
URL url = new URL(urls[0]);
connection = (HttpURLConnection) url.openConnection();
connection.connect();
InputStream stream = connection.getInputStream();
reader = new BufferedReader(new InputStreamReader(stream));
StringBuffer buffer = new StringBuffer();
String line;
while ((line = reader.readLine()) != null) {
buffer.append(line);
}
return buffer.toString();
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
if (connection != null) {
connection.disconnect();
}
try {
if (reader != null) {
reader.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
return null;
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
output.setText(result);
}
}
What is my mistake? Why I can't access to it? I saw it as a solution here but didn't get it to work:
https://stackoverflow.com/a/12252717/5743912
Hope you can help me now! :)

You probably want to fix this (remove leading slashes):
new JSONTask().execute("//http://kusber-web.de/JsonTest.txt");
In your JSONTask you can reference members of Patienten by using Patienten.this. So in onPostExecute you should change this:
output.setText(result);
to:
Patienten.this.output.setText(result);

Android HTTP connection and stream "gathering"

I "wrote" some code which should execute http request + stream download, however it does not seem to be working with the second part. It connects to the server, but without getting the expected data from it. The first few times it evena worked out, it displayed the html data from google, but afterwards,
I tried to optimize my code and threw something away, added something here and there, extended it by a class etc., which probably caused the "error". Here is my code:
public class MainActivity extends ActionBarActivity {
private static final String TAG = null;
TextView httpStuff;
public static String info;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
try {
AsyncDownload data = (AsyncDownload) new AsyncDownload().execute();
info = data.get();
httpStuff.setText(info);
} catch (Exception e){
e.printStackTrace();
}
}
public class AsyncDownload extends AsyncTask<Void, Void, String> {
protected String doInBackground(Void... params) {
Log.v(TAG, "Final Requsting URL is : :" + "google.com");
String line = "";
String responseData = null;
try {
StringBuilder sb = new StringBuilder();
String x = "";
URL httpurl = new URL("http://www.google.com");
URLConnection tc = httpurl.openConnection();
BufferedReader in = new BufferedReader(
new InputStreamReader(tc.getInputStream()));
while ((line = in.readLine()) != null) {
sb.append(line + "\n");
x = sb.toString();
}
responseData = new String(x);
}
catch (UnknownHostException uh){
Log.v("NewWebHelper", "Unknown host :");
uh.printStackTrace();
}
catch (FileNotFoundException e) {
Log.v("NewWebHelper", "FileNotFoundException :");
e.printStackTrace();
}
catch (IOException e) {
Log.v("NewWebHelper", "IOException :");
e.printStackTrace();
}
catch (Exception e) {
Log.v("NewWebHelper", "Exception :");
e.printStackTrace();
}
return responseData;
}
}
I just don't know what's the missing thing. I've been trying to solve this for hours with a big variety of data-passing versions of this, but nothing seems to be working. I'm counting on you, brainiacs.