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How to display Questions and Choices?

Im working on an Android Application that needed to display a Question(TextView) and Four possible answers(RadioGroup with RadioButtons). Im using a Web Server and MySql for connecting the database into my app. In order to get the data i converted the data into JSON using this method in PHP.
<?php
include_once 'db.php';
class Quiz{
private $db;
private $db_table = "aenglish_questions";
public function __construct(){
$this->db = new DbConnect();
}
public function getAllQuizQuestions(){
$json_array = array();
$query = "select * from aenglish_questions";
$result = mysqli_query($this->db->getDb(), $query);
if(mysqli_num_rows($result) > 0){
while ($row = mysqli_fetch_assoc($result)) {
$json_array["quiz_questions"][] = $row;
}
}
return $json_array;
}
}
?>
After getting the JSON data, i needed to display the first question and choices in the textview and radiobuttons in Android studio and when i click the next button it proceeds to the next question.
I`ve try this code and im getting an error message that says my ArrayList is empty.
private class AsyncJsonObject extends AsyncTask<String, Void, String> {
private ProgressDialog progressDialog;
#Override
protected String doInBackground(String... params) {
HttpClient httpClient = new DefaultHttpClient(new BasicHttpParams());
HttpPost httpPost = new HttpPost("http://192.168.1.11/LETIA/includes/index.php");
String jsonResult = "";
try {
HttpResponse response = httpClient.execute(httpPost);
jsonResult = inputStreamToString(response.getEntity().getContent()).toString();
System.out.println("Returned Json object " + jsonResult.toString());
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return jsonResult;
}
#Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
progressDialog = ProgressDialog.show(getActivity(), "Downloading Quiz","Wait....", true);
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
progressDialog.dismiss();
System.out.println("Resulted Value: " + result);
parsedObject = returnParsedJsonObject(result);
if(parsedObject == null){
return;
}
quizCount = parsedObject.size();
firstQuestion = parsedObject.get(0);
quizQuestion.setText(firstQuestion.getQuestion());
String[] possibleAnswers = firstQuestion.getAnswers().split(",");
optionOne.setText(possibleAnswers[0]);
optionTwo.setText(possibleAnswers[1]);
optionThree.setText(possibleAnswers[2]);
optionFour.setText(possibleAnswers[3]);
}
private StringBuilder inputStreamToString(InputStream is) {
String rLine = "";
StringBuilder answer = new StringBuilder();
BufferedReader br = new BufferedReader(new InputStreamReader(is));
try {
while ((rLine = br.readLine()) != null) {
answer.append(rLine);
}
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return answer;
}
}
I dont know what is the problem and im trying to find an answer for a couple of hours. I just needed it to get pass on my project and any help you provide will have a big impact in my study. Hope you guys can help me.
This is my code on putting the JSON into an ArrayList.
private List<QuizWrapper> returnParsedJsonObject(String result){
List<QuizWrapper> jsonObject = new ArrayList<QuizWrapper>();
JSONObject resultObject = null;
JSONArray jsonArray = null;
QuizWrapper newItemObject = null;
try {
resultObject = new JSONObject(result);
System.out.println("Testing the water " + resultObject.toString());
jsonArray = resultObject.optJSONArray("aenglish_questions");
} catch (JSONException e) {
e.printStackTrace();
}
for(int i = 0; i < jsonArray.length(); i++){
JSONObject jsonChildNode = null;
try {
jsonChildNode = jsonArray.getJSONObject(i);
int id = jsonChildNode.getInt("qae_id");
String question = jsonChildNode.getString("question");
String answerOptions = jsonChildNode.getString("choices");
int correctAnswer = jsonChildNode.getInt("answer");
newItemObject = new QuizWrapper(id, question, answerOptions, correctAnswer);
jsonObject.add(newItemObject);
} catch (JSONException e) {
e.printStackTrace();
}
}
return jsonObject;
}
Im having this Error
E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.pre_boardreviewer, PID: 26290
java.lang.IndexOutOfBoundsException: Index: 0, Size: 0
at java.util.ArrayList.get(ArrayList.java:437)
at com.example.recall.EnglishFragments.Question10Fragment$AsyncJsonObject.onPostExecute(Question10Fragment.java:164)
at com.example.recall.EnglishFragments.Question10Fragment$AsyncJsonObject.onPostExecute(Question10Fragment.java:123)
at android.os.AsyncTask.finish(AsyncTask.java:695)
at android.os.AsyncTask.access$600(AsyncTask.java:180)
at android.os.AsyncTask$InternalHandler.handleMessage(AsyncTask.java:712)
at android.os.Handler.dispatchMessage(Handler.java:106)
at android.os.Looper.loop(Looper.java:214)
at android.app.ActivityThread.main(ActivityThread.java:7156)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:494)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:975)

How to parse data from json(url) and send data to url

I am trying to send data to url from where i am parsing json data and i want to know can we edit json data in url if we created random json store from myjson.com or we have to maintain our own server to edit json data.Here i created random json store and i am parsing data from that url and i also wanted to edit the data in url thats the problem i was not able to do .Its not working.please help???
This was structure
[{"name":"pavan","hit":true}]
this was mainactivity code from where fetchdata executes in background
public class MainActivity extends AppCompatActivity {
Button click;
public static TextView data;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
click=(Button)findViewById(R.id.button);
data=(TextView)findViewById(R.id.fetcheddata);
click.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View v) {
fetchdata process=new fetchdata();
process.execute();
}
});
}
}
This is fetchdata class from where fetching data from url and displaying in text view of mainactivity
public class fetchdata extends AsyncTask<Void,Void,Void> {
String data="";
String dataparsed="";
String singleparsed="";
boolean flag=false;
#Override
protected Void doInBackground(Void... params) {
try {
URL url=new URL("https://api.myjson.com/bins/1854yb");
HttpURLConnection httpURLConnection=(HttpURLConnection) url.openConnection();
InputStream inputStream=httpURLConnection.getInputStream();
BufferedReader bufferedReader=new BufferedReader(new InputStreamReader(inputStream));
String line="";
while (line!=null)
{
line=bufferedReader.readLine();
data=data+line;
}
JSONArray JA=new JSONArray(data);
for(int i=0;i<JA.length();i++)
{
JSONObject JO= (JSONObject) JA.get(i);
singleparsed="Name:"+JO.get("name")+"\n"+"Feed key:"+JO.get("hit");
dataparsed=dataparsed+singleparsed;
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void result) {
super.onPostExecute(result);
MainActivity.data.setText(this.dataparsed);
JSONObject postData = new JSONObject();
try {
postData.put("name","sai");
postData.put("hit", false);
new senddata().execute("https://api.myjson.com/bins/1854yb", postData.toString());
} catch (JSONException e) {
e.printStackTrace();
}
}
}
This is senddata to url code from postexecute of fetchdata this was executing and nothing is happening in url please help i am working on this from 3 days
public class senddata extends AsyncTask<String,Void, String> {
String data="";
String dataparsed="";
String singleparsed="";
boolean flag=false;
#Override
protected String doInBackground(String... params) {
String data = "";
HttpURLConnection httpURLConnection = null;
try {
httpURLConnection = (HttpURLConnection) new URL(params[0]).openConnection();
httpURLConnection.setRequestMethod("POST");
httpURLConnection.setDoOutput(true);
DataOutputStream wr = new DataOutputStream(httpURLConnection.getOutputStream());
wr.writeBytes("PostData=" + params[1]);
wr.flush();
wr.close();
InputStream in = httpURLConnection.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader(in);
int inputStreamData = inputStreamReader.read();
while (inputStreamData != -1) {
char current = (char) inputStreamData;
inputStreamData = inputStreamReader.read();
data += current;
}
dataparsed=data;
} catch (Exception e) {
e.printStackTrace();
} finally {
if (httpURLConnection != null) {
httpURLConnection.disconnect();
}
}
return data;
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
Log.e("TAG", result);
}
}

This api doesn't accept any paramter after its url.
It is a get method Api url not post method . Try running it in post method in postman , it will give error.
If u run in get method ,it will produce same output ,even if u add something after url :-"https://api.myjson.com/bins/1854yb"

I think you have some issue with myJson in creating api. If you are a beginner in android your can also try with Link for ready made Api for Android
They have created different kind of Apis for understanding the json concept.
also get some update about PostMan Link for postman

Error while parsing JsonObject

I am trying to get JsonObject from DownloadTask. But I am getting array values that are stored in downloadData along with JsonObjects stored in jsonObjectText. Look at below in logs. Why my code return array with JsonObject, But I only log the content of the jsonObject variable.
Here picture of Logs:
Here is my Code :
package com.example.smarpitsingh.webview;
public class MainActivity extends AppCompatActivity {
String name = "Result";
String result = "",downloadedData,jsonObjectText;
URL url;
HttpURLConnection httpURLConnection;
InputStream inputStream;
InputStreamReader streamReader;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
DownloadTask downloadTask = new DownloadTask();
try {
downloadedData = downloadTask.execute("https://hacker-news.firebaseio.com/v0/topstories.json?print=pretty").get();
JSONArray jsonArray = new JSONArray(downloadedData);
for (int i=1; i<20; i++){
DownloadTask jasonTask = new DownloadTask();
jsonObjectText = jasonTask.execute("https://hacker-news.firebaseio.com/v0/item/"+jsonArray.getString(i)+".json?print=pretty").get();
Log.i(name,jsonObjectText);
}
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
}
public class DownloadTask extends AsyncTask<String,Void,String>{
#Override
protected String doInBackground(String... urls) {
try {
url = new URL(urls[0]);
httpURLConnection = (HttpURLConnection)url.openConnection();
inputStream = httpURLConnection.getInputStream();
streamReader = new InputStreamReader(inputStream);
int data = streamReader.read();
while (data != -1){
char count = (char)data;
result += count;
data = streamReader.read();
}
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return result;
}
}
`}`

Because you have got an array in your json:

Displaying database records in android using JAVA RESTful webservice

I am trying to display database record using java restful web service. I have able to create a login form using it but I cannot display the records on the database. I tried this code but its not working at all. When button is pressed nothing happens. Heres my code.
DriverDetails.java
class Details extends Activity {
TextView name1;
TextView plate1;
Button Btngetdata;
//URL to get JSON Array
private static String url = "http://192.168.254.108:8080/taxisafe/display/taxidetails";
//JSON Node Names
private static final String TAG_USER = "taxi";
private static final String TAG_NAME = "taxi_name";
private static final String TAG_EMAIL = "taxi_plate_no";
JSONArray user = null;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Btngetdata = (Button)findViewById(R.id.getdata);
Btngetdata.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
new JSONParse().execute();
}
});
}
private class JSONParse extends AsyncTask<String, String, JSONObject> {
#Override
protected void onPreExecute() {
super.onPreExecute();
name1 = (TextView)findViewById(R.id.name);
plate1 = (TextView)findViewById(R.id.plate);
}
#Override
protected JSONObject doInBackground(String... args) {
HttpConnection jParser = new HttpConnection();
// Getting JSON from URL
JSONObject json = jParser.getJSONFromUrl(url);
return json;
}
#Override
protected void onPostExecute(JSONObject json) {
try {
// Getting JSON Array
user = json.getJSONArray(TAG_USER);
JSONObject c = user.getJSONObject(0);
// Storing JSON item in a Variable
String name = c.getString(TAG_NAME);
String email = c.getString(TAG_EMAIL);
//Set JSON Data in TextView
name1.setText(name);
plate1.setText(email);
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
HttpConnection.java
public class HttpConnection {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public HttpConnection() {
}
public JSONObject getJSONFromUrl(String url) {
// Making HTTP request
try {
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}

I suggest adding Volley to your project
https://developer.android.com/training/volley/index.html
and following the example here https://developer.android.com/training/volley/request.html#request-json
You will not need to create your own HTTP request. Let Volley handle the network request using JSONObjectRequest

Error when parsing json result from http post on android app

I have a php script that returns this json array.
{"PID":"1","PName":"Guitar","Brand":"Fender","Price":"110","Cat#":"1","Typ#":"1"}
I am making a simple app that places these results into several text views. only one product is returned each time as above.
when I run the app I get this Error: org.json.JSONException: Value
{"Typ#":"1","Brand":"test","Cat#":"1","PName":"Test","PID":"2","Price":"120"}
of type org.json.JSONObject cannot be converted to JSONArray.
Here is my code. Is there something wrong with the json result or the code?
public class MainActivity extends ActionBarActivity {
TextView tvname;
TextView tvbrand;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tvname = (TextView) findViewById(R.id.tvName);
tvbrand = (TextView) findViewById(R.id.tvBrand);
Button btnPost = (Button) findViewById(R.id.btnPost);
btnPost.setOnClickListener(new View.OnClickListener() {
#Override
public void onClick(View view) {
new getPro().execute();
}
});
}//end of on create
private class getPro extends AsyncTask<String,String,Void>{
private ProgressDialog progressDialog = new ProgressDialog(MainActivity.this);
InputStream inputStream = null;
String result = "";
protected void onPreExecute() {
progressDialog.setMessage("Downloading your data...");
progressDialog.show();
progressDialog.setOnCancelListener(new DialogInterface.OnCancelListener() {
public void onCancel(DialogInterface arg0) {
getPro.this.cancel(true);
}
});
}
#Override
protected Void doInBackground(String... strings) {
String url_select = "http://10.0.2.2/OnetoOne/getProduct.php";
ArrayList<NameValuePair> param = new ArrayList<NameValuePair>();
param.add(new BasicNameValuePair("pid", "2"));
try {
// Set up HTTP post
// HttpClient is more then less deprecated. Need to change to URLConnection
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url_select);
httpPost.setEntity(new UrlEncodedFormEntity(param));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
// Read content & Log
inputStream = httpEntity.getContent();
} catch (UnsupportedEncodingException e1) {
Log.e("UnsupportedEncodingException", e1.toString());
e1.printStackTrace();
} catch (ClientProtocolException e2) {
Log.e("ClientProtocolException", e2.toString());
e2.printStackTrace();
} catch (IllegalStateException e3) {
Log.e("IllegalStateException", e3.toString());
e3.printStackTrace();
} catch (IOException e4) {
Log.e("IOException", e4.toString());
e4.printStackTrace();
}
// Convert response to string using String Builder
try {
BufferedReader bReader = new BufferedReader(new InputStreamReader(inputStream, "iso-8859-1"), 8);
StringBuilder sBuilder = new StringBuilder();
String line = null;
while ((line = bReader.readLine()) != null) {
sBuilder.append(line + "\n");
}
inputStream.close();
result = sBuilder.toString();
} catch (Exception e) {
Log.e("StringBuilding & BufferedReader", "Error converting result " + e.toString());
}
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
//parse JSON data
try {
JSONArray jArray = new JSONArray(result);
//JSONObject jObject = jArray.getJSONObject(0);
String anem = jArray.getJSONObject(0).getString("PName");
//String getname = jObject.getString("PName");
//String getbrand = jObject.getString("Brand");
tvname.setText(anem);
//tvbrand.setText(getbrand);
this.progressDialog.dismiss();
} catch (JSONException e) {
Log.e("JSONException", "Error: " + e.toString());
}
}
}//end of async
}//end of class
Any help would be greatly appreciated.

That's not an array it's an object
JSONObject jObject = new JSONObject(result);
String anem = jObject.getString("PName");
tvname.setText(anem);

{"Typ#":"1","Brand":"test","Cat#":"1","PName":"Test","PID":"2","Price":"120"} of type org.json.JSONObject cannot be converted to JSONArray.
You are trying to convert a JSONObject into a JSONArray, this is your error.
Use :
JSONOjbect jso = new JSONObject(result);
A JSONObject Start with { and end with }.
A JSONArray Start with [ and end with ].