Develop Reference

Jasper Reports: getting JSON data from a post rest service

I am trying to get JSON data from a rest service. I know this is pretty simple for a GET service where you only have to provide the URI and Jasper studio can pull the data but I want to do this for a post rest service that also consumes some JSON input.
Workflow will be something like:
Send userID in request header and some JSON parameters in request
body.
Get JSON data as output.
Use JSON data to build report.
I am new to Jasper and am using Jasper server 6 with Japser Studio 6 but I can't find any documentation to do something like this.
I would appreciate if anyone can point me in the right direction regarding this.
The closes thing I can find is this link. From there I get that I can create a constructor which will get the data from rest service but how do I serve it to the report? Also please note that the JSON object being retrieved here is a bit complex and will have at least 2 lists with any number of items.
EDIT:
Alright so my custom adapter is like this:
package CustomDataAdapter;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import net.sf.jasperreports.engine.JRDataSource;
import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JRField;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClientBuilder;
import org.json.JSONObject;
public class SearchAdapter implements JRDataSource {
/**
* This will hold the JSON returned by generic search service
*/
private JSONObject json = null;
/**
* Will create the object with data retrieved from service.
*/
public SearchAdapter() {
String url = "[URL is here]";
String request = "{searchType: \"TEST\", searchTxt: \"TEST\"}";
// Setting up post client and request.
HttpClient client = HttpClientBuilder.create().build();
HttpPost post = new HttpPost(url);
HttpResponse response = null;
post.setHeader("userId", "1000");
post.setHeader("Content-Type", "application/json");
// Setting up Request payload
HttpEntity entity = null;
try {
entity = new StringEntity(request);
post.setEntity(entity);
// do post
response = client.execute(post);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// Reading Server Response
try {
int statusCode = response.getStatusLine().getStatusCode();
if (statusCode != 200) {
throw new Exception("Search Failed");
}
BufferedReader in = new BufferedReader(new InputStreamReader(
response.getEntity().getContent()));
String inputLine;
StringBuffer resp = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
resp.append(inputLine);
}
in.close();
this.json = new JSONObject(resp.toString());
} catch (NullPointerException e) {
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/*
* (non-Javadoc)
*
* #see
* net.sf.jasperreports.engine.JRDataSource#getFieldValue(net.sf.jasperreports
* .engine.JRField)
*/
public Object getFieldValue(JRField field) throws JRException {
// TODO Auto-generated method
// stubhttp://community-static.jaspersoft.com/sites/default/files/images/0.png
return this.json;
}
/*
* (non-Javadoc)
*
* #see net.sf.jasperreports.engine.JRDataSource#next()
*/
public boolean next() throws JRException {
return (this.json != null);
}
/**
* Return an instance of the class that implements the custom data adapter.
*/
public static JRDataSource getDataSource() {
return new SearchAdapter();
}
}
I am able to create an adapter and the Test Connection feature in Jasper Studio also returns true but I cant get it to read any of the fields in the JSON and auto-generate the report. I only get a blank document. FYI the JSON is something like:
{
"key": "value",
"key": "value",
"key": [list],
"key": [list]
}

Well, I feel stupid now but the solution was pretty easy. Turns out you cant just return a JSON object. You need to return the fields and manually add the fields in the report.
For record purposes my final code look like this:
package CustomDataAdapter;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import net.sf.jasperreports.engine.JRDataSource;
import net.sf.jasperreports.engine.JRException;
import net.sf.jasperreports.engine.JRField;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.HttpClientBuilder;
import org.json.JSONException;
import org.json.JSONObject;
public class SearchAdapter implements JRDataSource {
/**
* This will hold the JSON returned by generic search service
*/
private JSONObject json = null;
/**
* Ensures that we infinitely calling the service.
*/
private boolean flag = false;
/**
* Will create the object with data retrieved from service.
*/
private void setJson() {
String url = "[URL is here]";
String request = "{\"searchType\": \"Test\", \"searchTxt\": \"Test\"}";
// Setting up post client and request.
HttpClient client = HttpClientBuilder.create().build();
HttpPost post = new HttpPost(url);
HttpResponse response = null;
post.setHeader("userId", "1000");
post.setHeader("Content-Type", "application/json");
// Setting up Request payload
StringEntity entity = null;
try {
entity = new StringEntity(request);
post.setEntity(entity);
// do post
response = client.execute(post);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
// Reading Server Response
try {
int statusCode = response.getStatusLine().getStatusCode();
if (statusCode != 200) {
// Thrown Exception in case things go wrong
BufferedReader in = new BufferedReader(new InputStreamReader(
response.getEntity().getContent()));
String inputLine;
StringBuffer resp = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
resp.append(inputLine);
}
in.close();
String ex = "Search Failed. Status Code: " + statusCode;
ex += "\n Error: " + resp.toString();
throw new Exception(ex);
}
BufferedReader in = new BufferedReader(new InputStreamReader(
response.getEntity().getContent()));
String inputLine;
StringBuffer resp = new StringBuffer();
while ((inputLine = in.readLine()) != null) {
resp.append(inputLine);
}
in.close();
this.json = new JSONObject(resp.toString());
} catch (NullPointerException e) {
e.printStackTrace();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
/*
* (non-Javadoc)
*
* #see
* net.sf.jasperreports.engine.JRDataSource#getFieldValue(net.sf.jasperreports
* .engine.JRField)
*/
#Override
public Object getFieldValue(JRField field) throws JRException {
// TODO Auto-generated method
// stubhttp://community-static.jaspersoft.com/sites/default/files/images/0.png
try {
return this.json.get(field.getName());
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
/*
* (non-Javadoc)
*
* #see net.sf.jasperreports.engine.JRDataSource#next()
*/
#Override
public boolean next() throws JRException {
if (this.json != null && !flag) {
flag = true;
return true;
} else {
return false;
}
}
/**
* Return an instance of the class that implements the custom data adapter.
*/
public static JRDataSource getDataSource() {
SearchAdapter adapter = new SearchAdapter();
adapter.setJson();
return adapter;
}
}

Json parse from URL

I am getting java.lang.NullPointerException when I run this. Does anyone know why this is happening and how I can fix it?
Please take a look at my code and let me know if you have any suggestions.
{"begin":[{"id":1,"name":"Andy","size":1}],"open":[{"id":1,"name":"Tom","size":2}]}
Fragment
public class MainFragment extends Fragment {
public MainFragment() {}
//URL to get JSON Array
private String url = "URL...";
//JSON Node Names
private static final String TAG_BEGIN = "begin";
private static final String TAG_ID = "id";
private static final String TAG_NAME = "name";
private static final String TAG_SIZE = "size";
JSONArray begin = null;
#Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
View rootView = inflater.inflate(R.layout.fragment_main, container, false);
new JSONParse().execute();
return rootView;
}
private class JSONParse extends AsyncTask<String, String, JSONObject> {
private ProgressDialog pDialog;
#Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(HomeActivity.this);
pDialog.setMessage("Getting Data ...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
#Override
protected JSONObject doInBackground(String... args) {
JSONParser jParser = new JSONParser();
// Getting JSON from URL
JSONObject json = jParser.getJSONFromUrl(url);
return json;
}
#Override
protected void onPostExecute(JSONObject json) {
pDialog.dismiss();
try {
// Getting JSON Array
begin = json.getJSONArray(TAG_BEGIN);
JSONObject c = begin.getJSONObject(0);
// Storing JSON item in a Variable
String id = c.getString(TAG_ID);
String name = c.getString(TAG_NAME);
String size = c.getString(TAG_SIZE);
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
JSONParser
import android.util.Log;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
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;
}
}
Error:
E/JSON Parser﹕ Error parsing data org.json.JSONException: Value <!DOCTYPE of type java.lang.String cannot be converted to JSONObject
FATAL EXCEPTION: main
java.lang.NullPointerException
at
...$MainFragment$JSONParse.onPostExecute(MainActivity.java:399)
at
...$MainFragment$JSONParse.onPostExecute(MainActivity.java:373)
Which is...
begin = json.getJSONArray(TAG_BEGIN);
and...
private class JSONParse extends AsyncTask<String, String, JSONObject> {
EDIT (Answer)
JSONParser
Inside of JSONParser I changed my code to this:
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONObject getJSONFromUrl(String url) {
// Making HTTP request
try {
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpUriRequest request = new HttpGet(url);
request.setHeader("Accept", "application/json");
HttpResponse response = httpClient.execute(request);
HttpEntity httpEntity = response.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;
}
}
Inside of onPostExecute
JSONArray begin = json.getJSONArray(TAG_BEGIN);
for (int i = 0; i < begin(); i++) {
try {
JSONObject b = = begin(i);
String id = b.getString(TAG_ID);
String name = b.getString(TAG_NAME);
String size = b.getString(TAG_SIZE);
} catch (JSONException e) {
e.printStackTrace();
}
}

First make sure your JSONObject is not null. Then slowly transverse line by line based off the type.
JSONArray begin = json.getJSONArray(TAG_BEGIN);
Then possibly do something like this?
for(int n = 0; n < begin.length(); n++)
{
JSONObject object = begin.getJSONObject(n);
// query through the array
String id = object.getString(TAG_ID);
String name = object.getString(TAG_NAME);
String size = object.getString(TAG_SIZE);
//Now do something with the strings
}
Of course you'd do the same thing with the TAG_OPEN. Let me know if this works, I'll gladly help as much as possible.

the error shows that the return string of you http request is not only the json data
something like <!DOCTYPE are includeed
please check you are request the right url, and the server handle the request correctly
you can use your browser visit the url you request and check the return result

I am not using a fragment but here is similar solution.
Change your url and key values for retrieving values from json. I didn't have your url so i used some other. Please check it out. Same concept except i am not using fragments but this json parsing code works just fine.
First of all, you have to deal with the network on main thread exception
Add:
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
in your class,
and
ADD this to ManiFestFile:
<uses-permission android:name="android.permission.INTERNET"/>
MainActivity.Java
package com.example.test;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.os.Bundle;
import android.os.StrictMode;
import android.util.Log;
import android.view.Menu;
public class MainActivity extends Activity {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Making HTTP request
String url = "http://api.androidhive.info/contacts/";
JSONParser jParser = new JSONParser();
// Getting JSON from URL
JSONObject json = jParser.getJSONFromUrl(url);
try {
// Getting JSON Array
JSONArray begin = json.getJSONArray("contacts");
JSONObject c = begin.getJSONObject(0);
// Storing JSON item in a Variable
String id = c.getString("id");
String name = c.getString("name");
String size = c.getString("email");
} catch (JSONException e) {
e.printStackTrace();
}
}
#Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.main, menu);
return true;
}
}
JSONParser.Java
package com.example.test;
import android.os.StrictMode;
import android.util.Log;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONObject getJSONFromUrl(String url) {
// Making HTTP request
try {
StrictMode.ThreadPolicy policy = new StrictMode.ThreadPolicy.Builder().permitAll().build();
StrictMode.setThreadPolicy(policy);
// 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;
}
}

async Task : connect to tcp server and send a string ,close connection

I am a beginner in android development,
I have to do the following when a button is clicked using a Async Task.
connect to a specific TCP server using ip and Port and Check if its connected?
on failure show a toast message
on success send a string to the tcp server
close the connection.
I had used the code below for connecting
try
{
s= new Socket("192.168.43.205",20108);
out = new BufferedWriter( new OutputStreamWriter(s.getOutputStream()));
BufferedReader in = new BufferedReader(new InputStreamReader(s.getInputStream()));
}
catch (UnknownHostException e) {
tv.setText(e.toString());
Log.v("Tcp", e.toString());
}
catch (IOException e) {
tv.setText(e.toString());
Log.v("Tcp",e.toString());
}
catch (Exception e) {
tv.setText(e.toString());
}
but this usually hangs when the server isn't available. Is there a fix for this?

Use AsyncTask to make connection and retrieve data
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.List;
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.impl.client.DefaultHttpClient;
import org.apache.http.message.BasicNameValuePair;
import android.content.Context;
import android.os.AsyncTask;
public class SendDataAsync extends AsyncTask<String, Void, String> {
Context mContext;
public SendDataAsync(Context context){
this.mContext = context;
}
#Override
protected String doInBackground(String... params) {
String str = params[0];
.
.
.
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost("YOUR_URL");
httpPost.addHeader("Content-type", "application/x-www-form-urlencoded");
BasicNameValuePair strBasicNameValuePair = new BasicNameValuePair("str", str);
.
.
.
List<NameValuePair> nameValuePairList = new ArrayList<NameValuePair>();
nameValuePairList.add(strBasicNameValuePair);
.
.
.
try {
UrlEncodedFormEntity urlEncodedFormEntity = new UrlEncodedFormEntity(nameValuePairList);
httpPost.setEntity(urlEncodedFormEntity);
try {
HttpResponse httpResponse = httpClient.execute(httpPost);
InputStream inputStream = httpResponse.getEntity().getContent();
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
BufferedReader bufferedReader = new BufferedReader(inputStreamReader);
StringBuilder stringBuilder = new StringBuilder();
String bufferedStrChunk = null;
while((bufferedStrChunk = bufferedReader.readLine()) != null){
stringBuilder.append(bufferedStrChunk);
}
return stringBuilder.toString();
} catch (ClientProtocolException cpe) {
System.out.println("Client Protocol Exception :" + cpe);
cpe.printStackTrace();
} catch (IOException ioe) {
System.out.println("IO Exception :" + ioe);
ioe.printStackTrace();
}
} catch (UnsupportedEncodingException uee) {
System.out.println("An Exception given because of UrlEncodedFormEntity argument :" + uee);
uee.printStackTrace();
}
return null;
}
#Override
protected void onPreExecute() {
super.onPreExecute();
}
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
}
#Override
protected void onCancelled() {
super.onCancelled();
this.cancel(true);
}
}

JSON reads me only objects, no arrays

I'm using Eclipse, for an application where I have to read a JSON file from an URL.
The code I'm using is this one:
http://collegewires.com/android/2012/06/json-parsing-in-android/
Ok, the CLASS which I'm using for reading JSON files is called Parser.java:
package com.cw.json;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;
public class Parser {
static InputStream is = null;
static JSONObject jsonObject = null;
static String json = "";
// class constructor
public Parser() {
}
public JSONObject getJSONFromUrl(String url) {
// Making HTTP request
try {
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException exception) {
exception.printStackTrace();
} catch (ClientProtocolException exception) {
exception.printStackTrace();
} catch (IOException exception) {
exception.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sBuilder = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sBuilder.append(line + "\n");
}
is.close();
json = sBuilder.toString();
} catch (Exception exception) {
exception.printStackTrace();
}
// Parsing the string to a JSON object
try {
jsonObject = new JSONObject(json);
} catch (JSONException exception) {
exception.printStackTrace();
}
// JSON String
return jsonObject;
}
}
I was using this code for reading a JSON file which is directly an ARRAY, but the code gives me an error.
My question is: is it possible to read an Array instead always reading an Object??
maybe using another class?

Try to modify your Parser.java to this, so you gat a Array not a Object. And please buy you a JAVA Book for beginners, so you do learn how to speak JAVA
public JSONArray getJSONFromUrl(String url) {
....
static JSONArray jsonArray = null;
....
// Parsing the string to a JSON Array
try {
jsonArray = new JSONArray(json);
} catch (JSONException exception) {
exception.printStackTrace();
}
return jsonArray;
}

Android, Web Services, AsyncTask please help a noob/make sure im starting right

Ive made edits since the orignal post Im making an android app that connects to an JSON API. Everything so far works ok except if there is a delay from the server. The UI of course can stop responding if it takes too long. Ive read that asynctask can solve my problem. Ive had a really ard time with the examples though.
Here is the restclient class making the http calls... parsing the json and storing custom objects to a public list that my other class can access.
package com.bde.dgcr;
import android.app.Activity;
import android.content.Context;
import android.os.AsyncTask;
import android.util.Log;
import android.view.View;
import android.widget.ListView;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
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.JSONException;
import org.json.JSONObject;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.util.ArrayList;
import java.util.List;
public class RestClient {
static List<ResponseHolder> list = new ArrayList<ResponseHolder>();
protected Context context = this.context;
private static String convertStreamToString(InputStream is) {
/*
* To convert the InputStream to String we use the BufferedReader.readLine()
* method. We iterate until the BufferedReader return null which means
* there's no more data to read. Each line will appended to a StringBuilder
* and returned as String.
*/
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;
try {
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return sb.toString();
}
/* This is a test function which will connects to a given
* rest service and prints it's response to Android Log with
* labels "Praeda".
*/
public void connect(String url) {
AsyncTask<String, Void, Void> connection = new AsyncTask<String, Void, Void>() {
protected Context context;
#Override
protected Void doInBackground(String... params) {
// Prepare a request object
HttpGet httpget = new HttpGet(params[0]);
// Execute the request
HttpResponse response;
HttpClient httpclient = new DefaultHttpClient();
try {
list.clear();
response = httpclient.execute(httpget);
// Examine the response status
Log.i("Praeda", response.getStatusLine().toString());
// Get hold of the response entity
HttpEntity entity = response.getEntity();
// If the response does not enclose an entity, there is no need
// to worry about connection release
if (entity != null) {
// A Simple JSON Response Read
InputStream instream = entity.getContent();
String result = convertStreamToString(instream);
// A Simple JSONObject Creation
//JSONObject json= new JSONObject(result);
JSONArray jsonArray = new JSONArray(result);
// A Simple JSONObject Parsing
for (int i = 0; i < (jsonArray.length()); i++) {
JSONObject json_obj = jsonArray.getJSONObject(i);
ResponseHolder rh = new ResponseHolder(json_obj);
list.add(rh);
}
instream.close();
}
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
#Override
protected void onPostExecute(Void aVoid) {
ListView listView1;
super.onPostExecute(aVoid); //To change body of overridden methods use File | Settings | File Templates.
ResponseHolderAdapter adapter = new ResponseHolderAdapter(context, R.layout.listview_item_row, RestClient.list);
listView1 = (ListView) findViewById(R.id.listView1);
View header = (View) getLayoutInflater().inflate(R.layout.listview_header_row, null);
listView1.addHeaderView(header);
listView1.setAdapter(adapter);
}
};
connection.execute(url);
}
}
Here is the class calling the static connect method and using the list for an adapter to go in a list view.
public class JsonGrabber extends Activity {
private final String API_KEY = "key";
private final String SECRET = "secret";
private String state;
private String city;
private String country;
private static String mode;
private String md5;
private String url;
CourseSearch cs;
private ListView listView1;
/**
* Called when the activity is first created.
*/
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.results);
Bundle extras = getIntent().getExtras();
state = extras.getString("state");
city = URLEncoder.encode(extras.getString("city"));
country = extras.getString("country");
mode = extras.getString("mode");
md5 = MD5.getMD5(API_KEY + SECRET + mode);
System.out.println(md5);
url = "http://www.api.com/?key=" + API_KEY + "&mode=" + mode + "&id=1&sig=" + md5;
String findByLocUrl = "http://www.api.com/?key=" + API_KEY + "&mode=" + mode + "&city=" + city + "&state=" + state + "&country=" + country + "&sig=" + md5;
System.out.println(findByLocUrl);
RestClient rc = new RestClient();
rc.connect(findByLocUrl);
//RestClient.connect(findByLocUrl);
/* if (RestClient.list.isEmpty())
{
setContentView(R.layout.noresults);
} else
{
ResponseHolderAdapter adapter = new ResponseHolderAdapter(this, R.layout.listview_item_row, RestClient.list);
listView1 = (ListView) findViewById(R.id.listView1);
View header = (View) getLayoutInflater().inflate(R.layout.listview_header_row, null);
listView1.addHeaderView(header);
listView1.setAdapter(adapter);
}
*/
}
}
Somehow Im supposed to mesh all this up into using an innerclass extending asyctask to do the API calls in the background parse the json add to my list and set up the adapter. I know i may have some object orientation problems and was hoping before i continue on with my app that you guys can make sure im going in the right direction. I have a few other classes I didnt include. Let me know if it will make more sense if I added the other classes. Thanks In Advance for any help you guys/girls may be able to offer.

You can rewrite your connect method using an AsyncTask like this:
public static void connect(String url) {
HttpClient httpclient = new DefaultHttpClient();
AsyncTask<String, Void, Void> connection = new AsyncTask<String, Void, Void>() {
#Override
protected Void doInBackground(String... params) {
// Prepare a request object
HttpGet httpget = new HttpGet(params[0]);
// Execute the request
HttpResponse response;
try {
list.clear();
response = httpclient.execute(httpget);
// Examine the response status
Log.i("Praeda", response.getStatusLine().toString());
// Get hold of the response entity
HttpEntity entity = response.getEntity();
// If the response does not enclose an entity, there is no need
// to worry about connection release
if (entity != null) {
// A Simple JSON Response Read
InputStream instream = entity.getContent();
String result= convertStreamToString(instream);
// A Simple JSONObject Creation
//JSONObject json= new JSONObject(result);
JSONArray jsonArray = new JSONArray(result);
// A Simple JSONObject Parsing
for (int i = 0; i < (jsonArray.length()); i++) {
JSONObject json_obj = jsonArray.getJSONObject(i);
ResponseHolder rh = new ResponseHolder(json_obj);
list.add(rh);
}
instream.close();
}
}
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
connection.execute(url);
}

If you want to do it right, you should use a contentprovider, service, and a database, here's a good tutorial:
http://mobile.tutsplus.com/tutorials/android/android-fundamentals-downloading-data-with-services/