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Android Get json response of website call

there are some some web site that call end point and recive a json response.
I would like to know how in myAndroid app i can call the web site and retrive the json data that he show.
Example: this is a drivenow site map
drivenow map link
if i open debug mode of browser i see this ajax call that give a josn response.
I would like to know i can call this website and take (grap) this response in my android app so i can use the json
Any idea? Help?
Thanks

You can perform GET/POST request using two ways.
Some 3rd party network request libraries
I would suggest using robospice. Using robospice you perform a network request and give it a POJO. For more info on POJO refer to the link below
https://github.com/stephanenicolas/robospice/wiki/Starter-Guide
What is RoboSpice Library in android
Using native Android/Java code
Use this function to get JSON from URL.
public static JSONObject getJSONObjectFromURL(String urlString) throws IOException, JSONException {
HttpURLConnection urlConnection = null;
URL url = new URL(urlString);
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.setReadTimeout(10000 /* milliseconds */);
urlConnection.setConnectTimeout(15000 /* milliseconds */);
urlConnection.setDoOutput(true);
urlConnection.connect();
BufferedReader br=new BufferedReader(new InputStreamReader(url.openStream()));
char[] buffer = new char[1024];
String jsonString = new String();
StringBuilder sb = new StringBuilder();
String line;
while ((line = br.readLine()) != null) {
sb.append(line+"\n");
}
br.close();
jsonString = sb.toString();
System.out.println("JSON: " + jsonString);
return new JSONObject(jsonString);}
Then use it like this:
try{
JSONObject jsonObject = getJSONObjectFromURL(String urlString);
// Parse your json here
} catch (IOException e) {
e.printStackTrace();
} catch (JSONException e) {
e.printStackTrace();
}
Do not forget to add Internet permission in your manifest
<uses-permission android:name="android.permission.INTERNET" />
For more info on parsing JSON visit
How to parse JSON in Android
Note
You don't have to manually parse your json if you use a 3rd party library.

Not able to POST to REST API

Today I'm making my first attempt of sending a POST request with a JSON to save some data, and I'm not being able to do so.
My app works by signing in, and then save, modify and delete data. It's already done in iOS, but since I'm new to Android, I'm not sure how to do it.
Here's my POST function:
public String POST(String targetURL, String urlParameters, String user, String pwd) {
URL url;
String u = targetURL;
HttpURLConnection connection = null;
try {
// Create connection
// u=URLEncoder.encode(u, "UTF-8");
url = new URL(u);
connection = (HttpURLConnection) url.openConnection();
// cambiarlo luego al usuario q esta logeado
String login = user + ":" + pwd;
String encoding = new String(org.apache.commons.codec.binary.Base64.encodeBase64(org.apache.commons.codec.binary.StringUtils.getBytesUtf8(login)));
connection.setRequestMethod("POST");
connection.setRequestProperty("Authorization", "Basic " + encoding);
connection.setRequestProperty("Content-Type", "plain/text");// hace q sirva con el string de json
connection.setRequestProperty("Content-Length", "" + Integer.toString(urlParameters.getBytes().length));
connection.setRequestProperty("Content-Language", "en-US");
connection.setUseCaches(false);
connection.setDoInput(true);
connection.setDoOutput(true);
connection.setReadTimeout(120000);
// Send request
DataOutputStream wr = new DataOutputStream(connection.getOutputStream());
wr.writeBytes(urlParameters);
wr.flush();
wr.close();
// Get Response
InputStream is = connection.getInputStream();
BufferedReader rd = new BufferedReader(new InputStreamReader(is));
String line;
StringBuffer response = new StringBuffer();
this.setResponseCode(connection.getResponseCode());
while ((line = rd.readLine()) != null) {
response.append(line);
response.append('\r');
}
rd.close();
return response.toString();
} catch (Exception e) {
e.printStackTrace();
return null;
} finally {
if (connection != null) {
connection.disconnect();
}
}
}
The method above is executed with Asynctask, and even if I use it to Login using Spring security, it works, and even I can save for internal usage the username, password, and secret token.
I dunno if I need to put the token in a header or something, because I already did that, with no positive results.
I'm supposing that the only permission I need to execute this is the internet one, so in my manifest file I specified that permission.
I'm going crazy with this issue, please help!
Thanks in advance.
EDIT:
Sorry guys, I'm kinda new to this way of asking, and also, not an English native speaker :P
The output I receive after sending the request, is the HTML of the page that handles logging in into the web app... I need like a json response or something like that to make sure the request was saved correctly

Try handling your cookies
CookieManager cookieManager = new CookieManager();
CookieHandler.setDefault(cookieManager);
This should be a singleton.

Android - How can I open a persistent HTTP connection that receives chunked responses?

I'm trying to establish a persistent HTTP connection to an API endpoint that publishes chunked JSON responses as new events occur. I would like to provide a callback that is called each time the server sends a new chunk of data, and keep the connection open indefinitely. As far as I can tell, neither HttpClient nor HttpUrlConnection provide this functionality.
Is there a way to accomplish this without using a TCP socket?

One solution would be to use a delimeter such as \n\n to separate each json event. You could remove blank lines from original json before sending. Calling setChunkedStreamingMode(0) allows you to read content as it comes in (rather than after the entire request has been buffered). Then you can simply go through each line, storing them, until a blank line is reached, then parse the stored lines as JSON.
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setChunkedStreamingMode(0);
conn.connect();
InputStream is = conn.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(is, "UTF-8"));
StringBuffer sBuffer = new StringBuffer();
String line;
while ((line = reader.readLine()) != null) {
if (line.length() == 0) {
processJsonEvent(sBuffer.toString());
sBuffer.delete(0, sBuffer.length());
} else {
sBuffer.append(line);
sBuffer.append("\n");
}
}

As far as I can tell, Android's HttpURLConnection doesn't support receiving chunks of data across a persistent HTTP connection; it instead waits for the response to fully complete.
Using HttpClient, however, works:
HttpClient httpClient = new DefaultHttpClient();
try {
HttpUriRequest request = new HttpGet(new URI("https://www.yourStreamingUrlHere.com"));
} catch (URISyntaxException e) {
e.printStackTrace();
}
try {
HttpResponse response = httpClient.execute(request);
InputStream responseStream = response.getEntity().getContent();
BufferedReader rd = new BufferedReader(new InputStreamReader(responseStream));
String line;
do {
line = rd.readLine();
// handle new line of data here
} while (!line.isEmpty());
// reaching here means the server closed the connection
} catch (Exception e) {
// connection attempt failed or connection timed out
}

How do I use the command: HttpEntity?

I wish to settle my long term problem by this question and hope you guys would help, but firstly; I have been having issues to connect to a HTTPS self-signed certificate server for almost 3 weeks. Despite the multiple solutions here, I cannot seem to resolve my problem. Probably I did not know how to use it properly or did not have some files or imported the correct libraries.
I came across some websites that requires me to download a certificate from the https site that I am trying to connect into, and when I did that. I have to do the some steps before I can use the certificate or keystore that I created. I got this solution from this website:
Android: Trusting SSL certificates
// Instantiate the custom HttpClient
DefaultHttpClient client = new MyHttpClient(getApplicationContext());
HttpGet get = new HttpGet("https://www.mydomain.ch/rest/contacts/23");
// Execute the GET call and obtain the response
HttpResponse getResponse = client.execute(get);
HttpEntity responseEntity = getResponse.getEntity();
I have a problem, after the last line, as stated above. What do I do with the responseEntity? How do I use it if I wish to display the https website on a WebView? Some help and explanation would be nice :)

If you want the content from the HttpEntity the correct way does not include calling HttpEntity#getContent() to retrieve a stream and doing tons of pointless stuff already available in the Android SDK.
Try this instead.
// Execute the GET call and obtain the response
HttpResponse getResponse = client.execute(get);
HttpEntity responseEntity = getResponse.getEntity();
// Retrieve a String from the response entity
String content = EntityUtils.toString(responseEntity);
// Now content will contain whatever the server responded with and you
// can pass it to your WebView using #loadDataWithBaseURL
Consider using WebView#loadDataWithBaseURL when displaying content - it behaves a lot nicer.

You need to call responseEntity.getContent() to get response in InputStream against your requested URL. Use that stream in your way to present data as you want. For example, if the expected data is String, so you may simply convert this stream into string with the following method:
/**
* Converts InputStream to String and closes the stream afterwards
* #param is Stream which needs to be converted to string
* #return String value out form stream or NULL if stream is null or invalid.
* Finally the stream is closed too.
*/
public static String streamToString(InputStream is) {
try {
StringBuilder sb = new StringBuilder();
BufferedReader tmp = new BufferedReader(new InputStreamReader(is),65728);
String line = null;
while ((line = tmp.readLine()) != null) {
sb.append(line);
}
//close stream
is.close();
return sb.toString();
}
catch (IOException e) { e.printStackTrace(); }
catch (Exception e) { e.printStackTrace(); }
return null;
}

InputStream is = responseEntity.getContent();
try{
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
StringBuilder sb = new StringBuilder();
sb.append(reader.readLine() + "\n");
String line="0";
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
String result=sb.toString();
is.close();
}catch(Exception e){
Log.e("log_tag", "Error converting result "+e.toString());
}
you will have all the content in the String "result"

How do I send a request to different page on the logged site

First, I want to connect to the site.
After, I want to get a data from different page with this connection
sample:
1- connect to http://site.com/Login with user pass
2- get a secret data from http://site.com/Secret
How do I do this, pleas help me...
OutputStreamWriter request = null;
url = new URL("http://site.com/Login");
String response = null;
EditText user = (EditText)this.findViewById(R.id.user);
EditText pass = (EditText)this.findViewById(R.id.pass);
String parameters ;
try {
System.setProperty("http.keepAlive", "true");
url = new URL("http://site.com/Home/Login");
httppost = (HttpURLConnection) url.openConnection();
httppost.setDoInput(true);
httppost.setDoOutput(true);
httppost.setRequestMethod("POST");
httppost.setRequestProperty("User-Agent", "Mozilla/5.0 Linux U Android 2.3.3 tr-tr HTC_DesireHD_A9191 Build/GRI40 AppleWebKit/533.1 KHTML, like Gecko Version/4.0 Mobile Safari/533.1");
httppost.setRequestProperty("Accept_Language", "en-US");
httppost.setRequestProperty("Connection", "Keep-Alive");
httppost.setRequestProperty("Content-Type", "application/x-www-form-urlencoded");
request = new OutputStreamWriter(httppost.getOutputStream());
parameters = "username="+user.getText()+"&password="+pass.getText();
request.write(parameters);
request.flush();
request.close();
String line = "";
InputStreamReader isr = new InputStreamReader(httppost.getInputStream());
BufferedReader reader = new BufferedReader(isr);
StringBuilder sb = new StringBuilder();
while ((line = reader.readLine()) != null)
{
sb.append(line + "\n");
}
response = sb.toString();
Toast.makeText(this,response, Toast.LENGTH_LONG).show();
isr.close();
reader.close();
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(getApplicationContext(), e.toString(), Toast.LENGTH_LONG).show();
}

You should use WebView and sorry but you can not get the webview content.
If you own the server-side code and you want to access from java then you should use an access token for more secure connection and get data by using JSON or XML. Or there is a much more secure connection type which is OAuth2.
If you don't own server, you should show the http://site.com/Login url in webview. When the user logins than you have cookie in your webview. You can use CookieManager http://developer.android.com/reference/android/webkit/CookieManager.html and send the data by using this cookie and get the result. This method is not easy and can differentiate according to server-side implementation.