We Keep Coding

Parsing JSON Result Android [duplicate]

This question already has answers here:
Sending and Parsing JSON Objects in Android [closed]
(11 answers)
Closed 7 years ago.
I am building an Android application that receives some data in JSON format. At the moment the result is very ugly. I want to display this data neatly in multiple TextViews in my application but I am not to sure how to do it. Source code below.
Main.java
import java.io.IOException;
import java.io.InputStream;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.BasicHttpContext;
import org.apache.http.protocol.HttpContext;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
public class Main extends Activity implements OnClickListener {
TextView txt1;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
findViewById(R.id.my_button).setOnClickListener(this);
}
#Override
public void onClick(View arg0) {
Button b = (Button)findViewById(R.id.my_button);
b.setClickable(false);
new LongRunningGetIO().execute();
}
private class LongRunningGetIO extends AsyncTask <Void, Void, String> {
protected String getASCIIContentFromEntity(HttpEntity entity) throws IllegalStateException, IOException {
InputStream in = entity.getContent();
StringBuffer out = new StringBuffer();
int n = 1;
while (n>0) {
byte[] b = new byte[4096];
n = in.read(b);
if (n>0) out.append(new String(b, 0, n));
}
return out.toString();
}
#Override
protected String doInBackground(Void... params) {
HttpClient httpClient = new DefaultHttpClient();
HttpContext localContext = new BasicHttpContext();
HttpGet httpGet = new HttpGet("https://api.myjson.com/bins/363s3");
String text = null;
try {
HttpResponse response = httpClient.execute(httpGet, localContext);
HttpEntity entity = response.getEntity();
text = getASCIIContentFromEntity(entity);
} catch (Exception e) {
return e.getLocalizedMessage();
}
return text;
}
protected void onPostExecute(String results) {
if (results!=null) {
txt1 = (TextView)findViewById(R.id.textView1);
txt1.setText(results);
}
Button b = (Button)findViewById(R.id.my_button);
b.setClickable(true);
}
}
}

i use retrofit for asynchronous execution use Callback

If what u mean is how to structure the data u receive from the json then you should look into json formatting frameworks (like 'Jackson' or 'Gson' or others).
If what u mean is how to make the textual json appear neatly in a textbox, jackson also appears to have an option to print the json neatly (try this: http://www.mkyong.com/java/how-to-enable-pretty-print-json-output-jackson/ )

What about trying something like,
JSONObject jsonObject = new JSONObject(jsonString);
By the way, Volley is a good library for any kind of requests.

Calling async task class not working

I'm sure I am doing something wrong, new to Android, I already have the URL stored in a string in a for loop, need to grab the image from that URL using AsyncTask. Quite new to Android so I am running into some issues. Any help is appreciated.
SecondClass.java
package edu.colum.iam.JSON;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.StatusLine;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONObject;
import android.app.Activity;
import android.os.Bundle;
import android.widget.TextView;
import android.widget.Toast;
public class SecondClass extends Activity {
private TextView first, second, third;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.second);
first = (TextView)findViewById(R.id.firsttv);
second = (TextView)findViewById(R.id.secondtv);
third = (TextView)findViewById(R.id.thirdtv);
String id = getIntent().getStringExtra("id");
System.out.println(id);
String response = readBuilding(id.trim());
System.out.println(response);
try {
JSONObject jsonObj = new JSONObject(response);
if(jsonObj.length()>0)
{
String CourseName = jsonObj.getString("CourseName");
String CourseNumber = jsonObj.getString("CourseNumber");
String CourseDescription = jsonObj.getString("CourseDescription");
JSONArray arrayOfImages = jsonObj.getJSONArray("Images");
String theImage = arrayOfImages.get(0).toString(); //getting first image in the array and returning the link as a string
int arrSize = arrayOfImages.length();
List<String> urlOfImage = new ArrayList<String>(arrSize);
first.setText("CourseName:- "+CourseName);
second.setText("CourseNumber:- "+CourseNumber);
third.setText("CourseDescription:- "+CourseDescription);
for(int i = 0; i < arrayOfImages.length(); ++i)
{
theImage = arrayOfImages.get(i).toString();
urlOfImage.add(theImage);
ImageDownloadTask(theImage);
}
}
} catch (Exception e){
e.printStackTrace();
}
}
public String readBuilding(String id)
{
return postJSON("http://iam.colum.edu/portfolio/api/course/"+id+"?json=True");
}
private String postJSON(String stringURL) {
StringBuilder builder = new StringBuilder();
// Create a new HttpClient and Post Header
HttpClient httpclient = new DefaultHttpClient();
HttpGet httpget = new HttpGet(stringURL);
try {
httpget.addHeader("Content-Type","application/json; charset=utf-8");
HttpResponse response = httpclient.execute(httpget);
StatusLine statusLine = response.getStatusLine();
int statusCode = statusLine.getStatusCode();
if (statusCode == 200) {
HttpEntity entity = response.getEntity();
InputStream content = entity.getContent();
BufferedReader reader = new BufferedReader(
new InputStreamReader(content));
String line;
while ((line = reader.readLine()) != null) {
builder.append(line);
}
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return builder.toString();
}
}
ImageDownloadTask.java
package edu.colum.iam.JSON;
import java.io.InputStream;
import java.lang.ref.WeakReference;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.os.AsyncTask;
import android.util.Log;
import android.widget.ImageView;
public class ImageDownloadTask extends AsyncTask<String, Void, Bitmap> {
/** The url from where to download the image. */
private String url;
/** Reference to the view which should receive the image */
private final WeakReference<ImageView> imageRef;
/**
* Constructor.
*
* #param imageView
* The ImageView which will receive the image.
*/
public ImageDownloadTask(ImageView imageView) {
imageRef = new WeakReference<ImageView>(imageView);
}
/**
* This function will be executed to download the image in a background
* process.
*
*/
#Override
protected Bitmap doInBackground(String... params) {
try {
InputStream in = new java.net.URL(url).openStream();
Bitmap bitmap = BitmapFactory.decodeStream(in);
return bitmap;
} catch (Exception e) {
Log.e("ImageDownload", e.getMessage());
}
return null;
}
/**
* This function will be called after the image download and attaches
* the bitmap to the ImageView.
*
*/
#Override
protected void onPostExecute(Bitmap bitmap) {
if (isCancelled()) {
bitmap = null;
}
if (imageRef != null) {
ImageView imageView = imageRef.get();
if (imageView != null) {
imageView.setImageBitmap(bitmap);
}
}
}
}

There might be more issues here (such as possibly accessing network on main thread?), but this ImageDownloadTask(theImage); won't actually execute your AsyncTask. It shouldn't even compile. You'd want something like new ImageDownloadTask(theImage).execute();

For downloading images by URL I recommend to use third part libraries. For example Picasso (http://square.github.io/picasso).
To download image you just need to write this:
Picasso.with(SecondClass.this).load(url).into(imageView);

Retrieving xml from webservice - Android

I am trying to get some data from a webservice, in my android app.
The code I am using is this:
#Override
protected String doInBackground(String... params) {
String highScore = null;
int points = 0;
try {
URI uri = new URI("http://vestsoft.somee.com/api/scores");
URL website = new URL(uri.toASCIIString());
InputStream inputStream = website.openStream();
InputSource input = new InputSource(inputStream);
SAXParserFactory saxp = SAXParserFactory.newInstance();
SAXParser sp = saxp.newSAXParser();
XMLReader xmlReader = sp.getXMLReader();
HighScoreHandler handler = new HighScoreHandler();
xmlReader.setContentHandler(handler);
xmlReader.parse(input); // Here is an exception thrown
highScore = handler.highScore.getUserName();
points = handler.highScore.getPoints();
} catch (Exception e) {
e.printStackTrace();
}
return highScore + " " + points;
}
I get an exception saying:
"At line 1, column 0: syntax error"
I don't know what I am doing wrong.
As you can see, the API I get my data from is:
http://vestsoft.somee.com/api/scores

Your XML lacks the correct header:
<?xml version="1.0" encoding="UTF-8"?>
Put that string at the top of your XML file and SAX Parser will stop bothering.

There are some really nice open source XML parsing tools out there to make this a lot easier. For example, to solve this with Simple XML, I would do it like this:
import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import org.simpleframework.xml.Serializer;
import org.simpleframework.xml.core.Persister;
import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import com.squareup.okhttp.OkHttpClient;
public class MainActivity extends Activity {
public static final String TAG = MainActivity.class.getSimpleName();
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button b = (Button) findViewById(R.id.button1);
b.setOnClickListener(new OnClickListener() {
#Override
public void onClick(View v) {
Runnable r = new Runnable() {
#Override
public void run() {
try {
URL website = new URL("http://vestsoft.somee.com/api/scores");
OkHttpClient client = new OkHttpClient();
HttpURLConnection conn = client.open(website);
conn.addRequestProperty("Accept", "application/xml");
InputStream stream = conn.getInputStream();
Serializer serializer = new Persister();
ArrayOfScore scoreArray = serializer.read(ArrayOfScore.class, stream);
// do something with the ArrayScore object here
} catch (Exception err) {
Log.i(TAG, err.toString());
}
}
};
new Thread(r).start();
}
});
}
}
This references two other classes, the XML annotated java classes. They are:
import java.util.List;
import org.simpleframework.xml.ElementList;
import org.simpleframework.xml.Root;
#Root
public class ArrayOfScore {
#ElementList(inline=true,required=false)
private List<Score> scores;
public List<Score> getScores() {
return scores;
}
}
And:
import org.simpleframework.xml.Element;
import org.simpleframework.xml.Root;
#Root(name="Score")
public class Score {
#Element(name="Id",required=false)
Integer Id;
#Element(name="Name",required=false)
String Name;
#Element(name="Points",required=false)
String Points;
#Element(name="dateTime",required=false)
String dateTime;
}
With this simple model you can parse nearly any XML you encounter and get the parsing into first class objects automatically. There are similar classes for JSON such as Gson

Consuming Restful WCF Service in Android

I am not sure what causing the request not to execute. I was trying to call a WCF Restful service in android, and I receive the error message "Request Error". Looking at the example, I don't see any reason why this example should not work. See below:
Here is the .Net Service:
[ServiceContract]
public interface ISampleService
{
[OperationContract]
[WebInvoke(
Method="POST", UriTemplate="/Login", BodyStyle= WebMessageBodyStyle.WrappedRequest, ResponseFormat = WebMessageFormat.Json, RequestFormat = WebMessageFormat.Json)]
string Login(string value);
}
public class SampleService : ISampleService
{
public string Login(string value)
{
string t = "";
try
{
//foreach (string s in value)
//{
// t = s;
//}
return t;
}
catch (Exception e)
{
return e.ToString();
}
}
}
Java:
package com.mitch.wcfwebserviceexample;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.ByteArrayEntity;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicHeader;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.params.HttpConnectionParams;
import org.apache.http.protocol.HTTP;
import org.json.JSONArray;
import org.json.JSONObject;
import org.json.JSONStringer;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.TextView;
import android.app.Activity;
public class MainActivity extends Activity implements OnClickListener {
private String values ="";
Button btn;
TextView tv;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
btn = (Button)this.findViewById(R.id.btnAccess);
tv = (TextView)this.findViewById(R.id.tvAccess);
btn.setOnClickListener(this);
}
#Override
public void onClick(View arg0) {
try
{
AsyncTaskExample task = new AsyncTaskExample(this);
task.execute("");
String test = values;
tv.setText(values);
} catch(Exception e)
{
Log.e("Click Exception ", e.getMessage());
}
}
public class AsyncTaskExample extends AsyncTask<String, Void,String>
{
private String Result="";
//private final static String SERVICE_URI = "http://10.0.2.2:8889";
private final static String SERVICE_URI = "http://10.0.2.2:65031/SampleService.svc";
private MainActivity host;
public AsyncTaskExample(MainActivity host)
{
this.host = host;
}
public String GetSEssion(String URL)
{
boolean isValid = true;
if(isValid)
{
HttpClient client = new DefaultHttpClient();
HttpPost post = new HttpPost("http://10.0.2.2:65031/SampleService.svc/Login");
try
{
List<NameValuePair> value = new ArrayList<NameValuePair>(1);
value.add(new BasicNameValuePair("value", "123456"));
post.setEntity(new UrlEncodedFormEntity(value));
HttpResponse response = client.execute(post) ;
BufferedReader rd = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
String line ="";
while((line = rd.readLine()) != null)
{
System.out.println(line);
}
}catch(Exception e)
{
Log.e("Error", e.getMessage());
}
}
return Result;
}
#Override
protected String doInBackground(String... arg0) {
android.os.Debug.waitForDebugger();
String t = GetSEssion(SERVICE_URI);
return t;
}
#Override
protected void onPostExecute(String result) {
// host.values = Result;
super.onPostExecute(result);
}
#Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
}
#Override
protected void onCancelled() {
// TODO Auto-generated method stub
super.onCancelled();
}
}
}

I finally got it to work they way that I want it to. The issue was that I was building the Array this way (see below section 1) and pass it to the JSONObject or JSONArray. I switched and build the Array using JSONArray and pass it to the JSONObject (see section 2). It works like a charm.
Section1: Wrong way to do it - (It may work this way if you were to look through the array and put them in a JSONArray. It's will be too much work when it can be done directly.)
String[][] Array = {
new String[]{"Example", "Test"},
new String[]{"Example", "Test"},
};
JSONArray jar1 = new JSONArray();
jar1.put(0, Array);
// Did not work
Section 2: The way I did it after long hours of trying and some very helpful tips and hints from #vorrtex.
**JSONArray jar1 = new JSONArray();
jar1.put(0, "ABC");
jar1.put(1, "Son");
jar1.put(2, "Niece");**
**JSONArray jarr = new JSONArray();
jarr.put(0, jar1);**
JSONArray j = new JSONArray();
j.put(0,"session");
JSONObject obj = new JSONObject();
obj.put("value", jarr);
obj.put("test", j);
obj.put("name","myName");
Log.d("Obj.ToString message: ",obj.toString());
StringEntity entity = new StringEntity(obj.toString());
Looking at the web service, and it has exactly what I was looking for.
Thanks for you help!!!!

Using AsyncTask, but experiencing unexpected behaviour

Please refer to the following code which continuously calls a new AsyncTask. The purpose of the AsyncTask is to make an HTTP request, and update the string result.
package room.temperature;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.concurrent.ExecutionException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;
public class RoomTemperatureActivity extends Activity {
String result = null;
StringBuilder sb=null;
TextView TemperatureText, DateText;
ArrayList<NameValuePair> nameValuePairs;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
TemperatureText = (TextView) findViewById(R.id.temperature);
DateText = (TextView) findViewById(R.id.date);
nameValuePairs = new ArrayList<NameValuePair>();
for (int i = 0; i < 10; i++) {
RefreshValuesTask task = new RefreshValuesTask();
task.execute("");
}
}
// The definition of our task class
private class RefreshValuesTask extends AsyncTask<String, Integer, String> {
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected String doInBackground(String... params) {
InputStream is = null;
try {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://mywebsite.com/roomtemp/tempscript.php");
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
}
catch(Exception e) {
Log.e("log_tag", "Error in http connection" + e.toString());
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
sb = new StringBuilder();
sb.append(reader.readLine());
is.close();
result=sb.toString();
}
catch(Exception e) {
Log.e("log_tag", "Error converting result " + e.toString());
}
return result;
}
#Override
protected void onProgressUpdate(Integer... values) {
super.onProgressUpdate(values);
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
//System.out.println(result);
setValues(result);
}
}
public void setValues(String resultValue) {
System.out.println(resultValue);
String[] values = resultValue.split("&");
TemperatureText.setText(values[0]);
DateText.setText(values[1]);
}
}
The problem I am experiencing relates to the AsyncTask in some way or the function setValues(), but I am not sure how. Essentially, I want each call to the AsyncTask to run, eventually in an infinite while loop, and update the TextView fields as I have attempted in setValues. I have tried since yesterday after asking a question which led to this code, for reference.
Oh yes, I did try using the AsyncTask get() method, but that didn't work either as I found out that it is actually a synchronous call, and renders the whole point of AsyncTask useless.

Use publishProgress(), and onProgressUpdate() methods, to publish progress, while executing some task in doInBackground() method.
so change your code to following:
package room.temperature;
import java.io.BufferedReader;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.concurrent.ExecutionException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.HttpClient;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import android.app.Activity;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.widget.TextView;
public class RoomTemperatureActivity extends Activity {
String result = null;
StringBuilder sb=null;
TextView TemperatureText, DateText;
ArrayList<NameValuePair> nameValuePairs;
#Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
TemperatureText = (TextView) findViewById(R.id.temperature);
DateText = (TextView) findViewById(R.id.date);
nameValuePairs = new ArrayList<NameValuePair>();
RefreshValuesTask task = new RefreshValuesTask();
task.execute("");
}
// The definition of our task class
private class RefreshValuesTask extends AsyncTask<String, Integer, String> {
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected String doInBackground(String... params) {
InputStream is = null;
for (int i = 0; i < 10; i++) {
try {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("http://mywebsite.com/roomtemp/tempscript.php");
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
is = entity.getContent();
}
catch(Exception e) {
Log.e("log_tag", "Error in http connection" + e.toString());
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
sb = new StringBuilder();
sb.append(reader.readLine());
is.close();
result=sb.toString();
publishProgress(result);
}
catch(Exception e) {
Log.e("log_tag", "Error converting result " + e.toString());
}
}
return result;
}
#Override
protected void onProgressUpdate(String... values) {
super.onProgressUpdate(values);
setValues(values);
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
//System.out.println(result);
setValues(result);
}
}
public void setValues(String resultValue) {
System.out.println(resultValue);
String[] values = resultValue.split("&");
TemperatureText.setText(values[0]);
DateText.setText(values[1]);
}
}