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Basic Android App Direction

I've created basic android apps in various programming classes that I have taken before using Eclipse and the Java Android SDK.
The app that I'd like to create would require users to enter information that would later be analyzed. I want people to be able to compare this data with other people's data so I'd like every entry that users make to be submitted to a database to later be queried when a person attempts to compare their data.
I'd like direction for how to accomplish this. Should I find a free hosting site and set up a Sql server or is there a better way to accomplish this?
Edit: Just for fun.

I am a very beginner android developer, and I have found that using cloud-stored online database like mongolab.com is very friendly for user submitted data. The communication between database and server will have to be done through JSON parsing and URI requests.
Here is example of code you can bind to a button that will send object stored in field tempData:
public void send(View view) {
String apiURI = "https://api.mongolab.com/api/1/databases/MYDATABASE/collections/USERSUBMITTEDDATA?apiKey="
+ apiKey;
try {
// make web service connection
final HttpPost request = new HttpPost(apiURI);
request.setHeader("Accept", "application/json");
request.setHeader("Content-type", "application/json");
// Build JSON string with GSON library
Gson gson = new Gson();
JsonElement jsonElement = gson.toJsonTree(tempData);
String json = gson.toJson(jsonElement);
StringEntity entity = new StringEntity(json);
Log.d("****Parameter Input****", "Testing:" + json);
request.setEntity(entity);
// Send request to WCF service
final DefaultHttpClient httpClient = new DefaultHttpClient();
new AsyncTask<Void, Void, Void>() {
#Override
public Void doInBackground(Void... arg) {
try {
HttpResponse response = httpClient.execute(request);
Log.d("WebInvoke", "Saving: "
+ response.getStatusLine().toString());
// Get the status of web service
BufferedReader rd = new BufferedReader(
new InputStreamReader(response.getEntity()
.getContent()));
// print status in log
String line = "";
while ((line = rd.readLine()) != null) {
Log.d("****Status Line***", "Webservice: " + line);
}
} catch (Exception e) {
Log.e("SendMail", e.getMessage(), e);
}
return null;
}
}.execute();
} catch (Exception e) {
e.printStackTrace();
}
}
And here is an example of code used to retrieve elements in the database:
public void load() {
String apiURI = "https://api.mongolab.com/api/1/databases/MYDATABASE/collections/USERSUBMITTEDDATA"
+ "?apiKey=" + apiKey;
Log.d("****Status Line***", "" + apiURI);
try {
// make web service connection
final StringBuilder builder = new StringBuilder();
final HttpGet request = new HttpGet(apiURI);
request.setHeader("Accept", "application/json");
request.setHeader("Content-type", "application/json");
final DefaultHttpClient httpClient = new DefaultHttpClient();
new AsyncTask<Void, Void, String>() {
#Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
doSomethingWithReceivedData(result); //THIS METHOD IS DEFINED IN BODY OF YOUR ACTIVITY
}
#Override
public String doInBackground(Void... arg) {
try {
HttpResponse response = httpClient.execute(request);
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);
}
Log.d("****Status Line***", "Success");
return builder.toString();
} else {
Log.d("****Status Line***",
"Failed to download file");
}
} catch (Exception e) {
Log.e("SendMail", e.getMessage(), e);
}
return null;
}
}.execute();
} catch (Exception e) {
e.printStackTrace();
}
}

You should have a data base to store the data. Like mentioned above, the data base is good to be in MySQL (SQL). Your application should have a method that can POST the results to the server, where the server will read the string send and retrieve and store the data.
A good start is to read about JSON
and read also about Asynctask
Also you need to know how to build your sever part. A good idea is to start with PHP, but I am not an expert on that field.
I hope this helps you start your project.

Simple, no DB required.
Usergrid by Apigee is exactly what you are looking for!
You can store each user's details
Retrieve stored data
Send events and receive event callbacks across devices
Best of all - no server side code. Only APIs
FYI This is the direction you should be heading even if you know how to code a server.
PS: I don't work for apigee or usergrid.

Android: send post that has no response

In my app, I need to send all sorts of POST requests to a server. some of those requests have responses and others don't.
this is the code I'm using to send the requests:
private static final String TAG = "Server";
private static final String PATH = "http://10.0.0.2:8001/data_connection";
private static HttpResponse response = null;
private static StringEntity se = null;
private static HttpClient client;
private static HttpPost post = null;
public static String actionKey = null;
public static JSONObject sendRequest(JSONObject req) {
try {
client = new DefaultHttpClient();
actionKey = req.getString("actionKey");
se = new StringEntity(req.toString());
se.setContentEncoding(new BasicHeader(HTTP.CONTENT_ENCODING, "application/json"));
se.setContentType(new BasicHeader(HTTP.CONTENT_TYPE, "application/json"));
post = new HttpPost(PATH);
post.setEntity(se);
Log.d(TAG, "http request is being sent");
response = client.execute(post);
Log.d(TAG, "http request was sent");
if (response != null) {
InputStream in = response.getEntity().getContent();
String a = convertFromInputStream(in);
in.close();
return new JSONObject(a);
}
} catch (UnsupportedEncodingException e) {
Log.d(TAG, "encoding request to String entity faild!");
e.printStackTrace();
} catch (ClientProtocolException e) {
Log.d(TAG, "executing the http POST didn't work");
e.printStackTrace();
} catch (IOException e) {
Log.d(TAG, "executing the http POST didn't work");
e.printStackTrace();
} catch (JSONException e) {
Log.d(TAG, "no ActionKey");
e.printStackTrace();
}
return null;
}
private static String convertFromInputStream(InputStream in)
throws IOException {
BufferedReader br = new BufferedReader(new InputStreamReader(in));
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = br.readLine()) != null) {
sb.append(line);
}
return (sb.toString());
}
This is the code for the AsyncTask class that sends the request:
class ServerRequest extends AsyncTask<JSONObject, Void, JSONObject> {
#Override
protected JSONObject doInBackground(JSONObject... params) {
JSONObject req = params[0];
JSONObject response = Server.sendRequest(req);
return response;
}
#Override
protected void onPostExecute(JSONObject result) {
// HANDLE RESULT
super.onPostExecute(result);
}
}
my problem starts when the server doesn't return a response. the AsyncTask thread stays open even after the work is done because the HTTPClient never closes the connection.
Is there a way to not wait for a response? this is something that will definitely add a lot of overhead to the server since all the Android apps trying to connect to it will keep the connection alive, and will probably cause many problems on the app itself.
Basically, what I'm looking for is a method that will allow me to send to POST message and kill the connection right after the sending of the request since there is no response coming my way.

Just, Set ConnectionTimeOut with HttpClient Object, (Code is for your understanding in your case it may be different)
int TIMEOUT_MILLISEC = 30000;
HttpParams httpParams = new BasicHttpParams();
HttpConnectionParams.setConnectionTimeout(httpParams, TIMEOUT_MILLISEC);
HttpConnectionParams.setSoTimeout(httpParams, TIMEOUT_MILLISEC);
HttpClient httpclient = new DefaultHttpClient(httpParams);
HttpPost httppost = new HttpPost(url);
httppost.addHeader("Content-Type", "application/json");
Now, It will terminate the Connection after TimeoOut you defined. But be sure this will throw TimeOutException so You have to handle this exception in your HttpRequest.. (Use Try -catch)
EDIT: Or you can use HttpRequestExecutor class.
From class HttpRequestExecutor of package org.apache.http.protocol
protected boolean canResponseHaveBody (HttpRequest request, HttpResponse response)
Decide whether a response comes with an entity. The implementation in this class is based on RFC 2616. Unknown methods and response codes are supposed to indicate responses with an entity.
Derived executors can override this method to handle methods and response codes not specified in RFC 2616.

Creating a thread in android not working

I have a method that I'm calling but, for newer versions of Android it fails. Apparently, this is due to the lack of threading. My method is to send a message to my server. This is the code (sans threading)
public String sendMessage(String username, Editable message){
BufferedReader in = null;
String data = null;
try{
DefaultHttpClient client = new DefaultHttpClient();
URI website = new URI("http://abc.com/user_send.php?username="+username+"&message="+message);
HttpPost post_request = new HttpPost();
post_request.setURI(website);
HttpGet request = new HttpGet();
request.setURI(website);
//executing actual request
HttpResponse response = client.execute(request);
in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
StringBuffer sb = new StringBuffer("");
String l = "";
String nl = System.getProperty("line.separator");
while ((l = in.readLine()) != null) {
sb.append(l);
}
in.close();
data = sb.toString();
return data;
}catch (Exception e){
return "ERROR";
}
}
Now, just trying to put a thread around it:
public String sendMessage(String username, Editable message){
BufferedReader in = null;
String data = null;
Thread sendThread = new Thread(){
try{
DefaultHttpClient client = new DefaultHttpClient();
URI website = new URI("http://thenjtechguy.com/njit/gds/user_send.php?username="+username+"&message="+message);
HttpPost post_request = new HttpPost();
post_request.setURI(website);
HttpGet request = new HttpGet();
request.setURI(website);
//executing actual request
HttpResponse response = client.execute(request);
in = new BufferedReader(new InputStreamReader(response.getEntity().getContent()));
StringBuffer sb = new StringBuffer("");
String l = "";
String nl = System.getProperty("line.separator");
while ((l = in.readLine()) != null) {
sb.append(l);
}
in.close();
data = sb.toString();
return data;
}catch (Exception e){
return "ERROR";
}
} sendThread.start();
}
But that doesn't work. What am I doing wrong? Also, if you notice I'm breaking any fundamental rules in android regarding the HttpClient, please let me know.

Your implementation is not correct - you did not override run() method
class SendThread extends Thread {
public void run(){
//add your implementation here
}
}
Tow start the thread
SendThread sendThread = new SendThread();
sendThread.start();

Better to a head and use AsyncTask concept.
AsyncTask enables proper and easy use of the UI thread. This class allows to perform background operations and publish results on the UI thread without having to manipulate threads and/or handlers.
Refer this LINK for sample implementation

Reading line from website

I am making a little program thath will read data from website. String in the html file is already managed every info is divided with ; . Now i should read complete line here is example of this line:
14:47;24.02.12;18.7°C;18.7°C;285;0.5m/s; 6:48;17:37; Warm ;36;1.8;0.0;
So first how should i read them with HTTP Get or is there anything other? And then i would like to save each info, they are seperated with ; into a variable. And how should i cut each info from this line.

You definitely need to do some homework, but this methods will help you:
public static String getContentFromUrl(String url) throws ClientProtocolException, IOException {
HttpClient httpClient = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(url);
HttpResponse response;
response = httpClient.execute(httpGet);
HttpEntity entity = response.getEntity();
if (entity != null) {
InputStream inStream = entity.getContent();
String result = HttpService.convertStreamToString(inStream);
inStream.close();
return result;
}
return null;
}
private static String convertStreamToString(InputStream is) {
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 allows you to get data from a URL. Then lookup String.split to chop your string into usable entities.
Hope this helps!

Use GET request to fetch the data from the website
Separate the string-data from the HTML-markup
Parse the string into multiple strings or a list of strings, using ';' as the delimiter.
Android Java SDK String reference

Set cookie from HTTP Request

I have get a correct login using HttpRequest to work. It prints the correct html form of the logn page in my toast (just for testing). Now I want to set a cookie from that request. How is this possible?
If it necessary I can provide some code.
I already know about the CookieManager class, but how can I successfully do it?
Thanks in advance!
My code:
public String getPostRequest(String url, String user, String pass) {
HttpClient postClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse response;
try {
List<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(2);
nameValuePairs.add(new BasicNameValuePair("login", user));
nameValuePairs.add(new BasicNameValuePair("pass", pass));
httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs, HTTP.UTF_8));
response = postClient.execute(httpPost);
if(response.getStatusLine().getStatusCode() == 200) {
HttpEntity entity = response.getEntity();
if (entity != null) {
InputStream instream = entity.getContent();
String result = convertStreamToString(instream);
instream.close();
return result;
}
}
} catch (Exception e) {}
Toast.makeText(getApplicationContext(),
"Connection failed",
Toast.LENGTH_SHORT).show();
return null;
}
private String convertStreamToString(InputStream is) {
BufferedReader reader = new BufferedReader(new InputStreamReader(is));
StringBuilder sb = new StringBuilder();
String line = null;
try {
while ((line = reader.readLine()) != null) {
sb.append(line);
}
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
is.close();
} catch (IOException e) {
e.printStackTrace();
}
}
return sb.toString();
}
Well, this is pretty much it. convertStreamToString() function converts the InputStream into a String (plain HTML code), which I "toast" out to just test it (so it work), so the code is working though. Now to set the cookie. :-)
This is what I've reached for now:
// inside my if (entity != null) statement
List<Cookie> cookies = postClient.getCookieStore().getCookies();
String result = cookies.get(1).toString();
return result;
When I have logged in, the CookieList id 1 contains a value, otherwise the value is standard. So for now I know the difference in value, but how can I continue?

I think Android ships with Apache HttpClient 4.0.
You can check Chapter 3. HTTP state management topic from HttpClient Tutorial.
You can also refer similar questions on SO:
Android project using httpclient --> http.client (apache), post/get method
How do I manage cookies with HttpClient in Android and/or Java?
Also Check this example for usage: http://svn.apache.org/repos/asf/httpcomponents/httpclient/branches/4.0.x/httpclient/src/examples/org/apache/http/examples/client/ClientFormLogin.java