Develop Reference

Android - How to download a URL’s http contents which appear on scrolling down?

I have written an Android application to download HTTP contents of following URL: https://www.forbes.com/celebrities/list/
I want to use RegEx to extract image and name of the celebrities from HTML. But unfortunately, HTML content of celebrities list (<tr></tr> tags) only appears when user is “scrolling down”. In fact, my program doesn’t download any <tr></tr> tags inside <tbody> tag.
<tbody id="list-table-body">
</tbody>
How can I fix this problem?
DownloadWebContent Class:
public class DownloadWebContent extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... urls) {
StringBuilder output = new StringBuilder();
try {
URL url = new URL(urls[0]);
HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
InputStream inputStream = httpURLConnection.getInputStream();
InputStreamReader inputStreamReader = new InputStreamReader(inputStream);
int read = inputStreamReader.read();
while (read != -1) {
char character = (char) read;
output.append(character);
read = inputStreamReader.read();
}
return output.toString();
} catch (Exception e) {
Log.i("HTML_Error", e.getMessage());
return "Failed!";
}
}
}
onCreate Method:
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
TextView textView = findViewById(R.id.textView);
DownloadWebContent downloadWebContent = new DownloadWebContent();
try {
String htmlContent = downloadWebContent.execute("https://www.forbes.com/celebrities/list/").get();
String htmlContentReplaced= htmlContent.replace("\"", "");
textView.setText(htmlContentReplaced);
} catch (Exception e) {
e.printStackTrace();
}
}

Android : take Data in ListView

Actually in my project, I'm blocked. So, for the first time I ask the community of Stackoverflow. I'm new in development.
So, I have a MySql with my datas and I wan't to see in my application the items of users.
For that, I've this :
public class SuccessActivity extends AppCompatActivity {
public static final int CONNECTION_TIMEOUT = 10000;
public static final int READ_TIMEOUT = 15000;
private ListView listView;
protected String meubles[] = new String[100];
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_success);
Intent intent = getIntent();
String id = intent.getStringExtra("id");
this.listView = (ListView) findViewById(R.id.liste);
new SuccessActivity.Recup().execute(id);
}
//PRIVATE CLASSE POUR AFFICHER LES MEUBLES
private class Recup extends AsyncTask<String, String, String> {
HttpURLConnection conn;
URL url = null;
#Override
protected String doInBackground(String... params) {
try {
//url d'ou reside mon fichier php
url = new URL("http://opix-dev.fr/mytinyhomme/personne/afficher.meuble.php");
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return "exception";
}
try {
// parametrage du HttpURLConnection pour recevoir et envoyer des donner à mysql
conn = (HttpURLConnection) url.openConnection();
conn.setReadTimeout(READ_TIMEOUT);
conn.setConnectTimeout(CONNECTION_TIMEOUT);
conn.setRequestMethod("POST");
// setDoInput and setDoOutput method depict handling of both send and receive
conn.setDoInput(true);
conn.setDoOutput(true);
// Append parameters to URL
Uri.Builder builder = new Uri.Builder()
.appendQueryParameter("id", params[0]);
String query = builder.build().getEncodedQuery();
// Open connection for sending data
OutputStream os = conn.getOutputStream();
BufferedWriter writer = new BufferedWriter(
new OutputStreamWriter(os, "UTF-8"));
writer.write(query);
writer.flush();
writer.close();
os.close();
conn.connect();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
return "exception";
}
try {
int response_code = conn.getResponseCode();
// Check if successful connection made
if (response_code == HttpURLConnection.HTTP_OK) {
// Read data sent from server
InputStream input = conn.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(input));
StringBuilder result = new StringBuilder();
String line;
while ((line = reader.readLine()) != null) {
result.append(line);
}
// Pass data to onPostExecute method
return (result.toString());
} else {
return ("unsuccessful");
}
} catch (IOException e) {
e.printStackTrace();
return "exception";
} finally {
conn.disconnect();
}
}
#Override
protected void onPostExecute(String resulta) {
//this method will be running on UI thread
if (resulta.equalsIgnoreCase("false")) {
} else if (resulta.equalsIgnoreCase("exception") || resulta.equalsIgnoreCase("unsuccessful")) {
} else {
try {
JSONArray nom = new JSONArray(resulta);
System.out.println(nom);
String meubles[] = new String[100];
for (int i = 0; i < nom.length(); i++){
JSONObject jsonobject = nom.getJSONObject(i);
meubles[i]= jsonobject.getString("nom");
System.out.println(jsonobject);
System.out.println(meubles);
item.setText( meubles[i]);
}
System.out.println(meubles);
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
}
The file.php is correct because the JSONArray in System.print is ok But I've try with some TextView for display the board at the end, but I did not succeed.
How I can use the meuble[0] , meuble[1], meuble[2](it's board of String name of items) in a ListView ?

Here is what you need to do to show your data in a listview,
Modified onPostExecute() method:
#Override
protected void onPostExecute(String resulta) {
//this method will be running on UI thread
if (resulta.equalsIgnoreCase("false")) {
} else if (resulta.equalsIgnoreCase("exception") || resulta.equalsIgnoreCase("unsuccessful")) {
} else {
try {
JSONArray nom = new JSONArray(resulta);
System.out.println(nom);
String meubles[] = new String[100];
for (int i = 0; i < nom.length(); i++){
JSONObject jsonobject = nom.getJSONObject(i);
meubles[i]= jsonobject.getString("nom");
System.out.println(jsonobject);
System.out.println(meubles);
}
ArrayAdapter<String> listAdapter=new ArrayAdapter<>(this,android.R.layout.simple_list_item_1,meubles);
listView.setAdapter(listAdapter);
System.out.println(meubles);
} catch (JSONException e) {
e.printStackTrace();
}
}
}
What's added?
You need an adapter to show items in a listview. You can create your custom adapter class by extending an arrayadapter or you can use an arrayadapter without customizing it as shown.
Added code:
Create a new adapter,
ArrayAdapter listAdapter=new ArrayAdapter<>(this,android.R.layout.simple_list_item_1,list);
Set adapter for your listview,
listView.setAdapter(listAdapter);

HttpURLConnection crashes application

I want to receive and send data with a web server but the code does not work
What do I do for this code to work?
Note this code inside onCreate
try {
URL url = new URL("http://myweb.com/");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
InputStream Stream = connection.getInputStream();
InputStreamReader reader = new InputStreamReader(Stream);
BufferedReader b = new BufferedReader(reader);
StringBuilder s = new StringBuilder();
String str ="";
while ((str = b.readLine())!=null) {
s.append(str);
}
String data = s.toString();
TextView myText = (TextView) findViewById(R.id.Text);
myText.setText(data);
} catch (MalformedURLException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}

Make sure that you do network-related tasks on a separate thread in Android. Also, check that you have the INTERNET permission set.
If you want to then update the UI from another thread, you have to use
runOnUiThread (new Runnable () {
public void run() {
//update ui in here
}
}

All your code runs in Main thread which should be always used for setting up the UI and to listen for UI events such as on click listeners.
Network calls are not allowed on this thread as they might take long time. Use AsyncTask API of android which is designed for running code in separate thread.
Create a class like one below for all GET request tasks.
public class DownloadTask extends AsyncTask<String, Void, Integer> {
private String TAG = "InDownloadTask";
private DownloadCallback callback;
private String data;
public DownloadTask(DownloadCallback cb){
callback = cb;
}
#Override
protected Integer doInBackground(String... params) {
Integer result = 0;
HttpURLConnection urlConnection;
try {
URL url = new URL(params[0]);
urlConnection = (HttpURLConnection) url.openConnection();
int statusCode = urlConnection.getResponseCode();
if (statusCode == 200) {
BufferedReader r = new BufferedReader(new InputStreamReader(urlConnection.getInputStream()));
StringBuilder response = new StringBuilder();
String line;
while ((line = r.readLine()) != null) {
response.append(line);
}
data = response.toString();
result = 1;
} else {
result = 0;
}
} catch (Exception e) {
Log.d(TAG, e.getLocalizedMessage());
}
return result;
}
#Override
protected void onPostExecute(Integer integer) {
super.onPostExecute(integer);
callback.onFinishDownload(data, integer);
}
}
Create a callback interface that we use for the above class.
public interface DownloadCallback {
public void onFinishDownload(String data, Integer result);
}
Now from your activity onCreate
String url = "http://myweb.com/";
new DownloadTask(new DownloadCallback() {
public void onFinishDownload(String data, Integer result) {
if(result == 1)
myText.setText(data);
else
myText.setText("Error");
}
}).execute(url);
If you have many network related operations, use a Network library such as Volley which will take care of this.

Get unique item id from item list in Android

I was creating android project in that i am using itemlist view and pagination . while clicking on that particular item i want to get that item id.but i am not getting the unique id.
When i use position then each and every page it is getting form 0-9.
i have the field 'audit_id'. i want to assign this values as item id and i want to get . whether it is possible?
My Code is :
private class AsyncLogin extends AsyncTask<String, String, StringBuilder> {
ProgressDialog pdLoading = new ProgressDialog(Tblview.this);
HttpURLConnection conn;
URL url = null;
#Override
protected void onPreExecute() {
super.onPreExecute();
//this method will be running on UI thread
pdLoading.setMessage("\tLoading...");
pdLoading.setCancelable(false);
pdLoading.show();
}
#Override
protected StringBuilder doInBackground(String... params) {
try {
// Enter URL address where your php file resides
url = new URL("http://192.168.1.99/ashwad/ims/webservices/alldata.php");
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
Toast.makeText(getApplicationContext(), "URL Exception", Toast.LENGTH_LONG).show();
e.printStackTrace();
return null;
}
try {
// Setup HttpURLConnection class to send and receive data from php and mysql
conn = (HttpURLConnection) url.openConnection();
conn.setReadTimeout(READ_TIMEOUT);
conn.setConnectTimeout(CONNECTION_TIMEOUT);
conn.setRequestMethod("POST");
// setDoInput and setDoOutput method depict handling of both send and receive
conn.setDoInput(true);
conn.setDoOutput(true);
// Append parameters to URL
Uri.Builder builder = new Uri.Builder()
.appendQueryParameter("user_id", "sdfa")
.appendQueryParameter("password", "asffs");
String query = builder.build().getEncodedQuery();
// Open connection for sending data
OutputStream os = conn.getOutputStream();
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));
writer.write(query);
writer.flush();
writer.close();
os.close();
conn.connect();
} catch (IOException e1) {
// TODO Auto-generated catch block
e1.printStackTrace();
return null;
}
try {
int response_code = conn.getResponseCode();
// Check if successful connection made
if (response_code == HttpURLConnection.HTTP_OK) {
// Read data sent from server
InputStream input = conn.getInputStream();
BufferedReader reader = new BufferedReader(new InputStreamReader(input));
BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(conn.getInputStream()));
result = new StringBuilder();
String next1;
while ((next1 = bufferedReader.readLine()) != null) {
result.append(next1 + "\n");
}
Log.e("dfasf",result.toString());
}
} catch (IOException e) {
e.printStackTrace();
} finally {
conn.disconnect();
}
return result;
}
#Override
protected void onPostExecute(StringBuilder s) {
super.onPostExecute(s);
try {
JSONArray login;
JSONObject obj = new JSONObject(s.toString());
if(s.toString().contains("Result")) {
data = new ArrayList<String>();
login = obj.getJSONArray("Result");
for(int i=0;i<login.length();i++) {
JSONObject c = login.getJSONObject(i);
productsArray = c.getJSONArray(Latest_Products);
TOTAL_LIST_ITEMS=productsArray.length();
int val = TOTAL_LIST_ITEMS%NUM_ITEMS_PAGE;
val = val==0?0:1;
pageCount = (TOTAL_LIST_ITEMS/NUM_ITEMS_PAGE)+val;
for (int j = 0; j < productsArray.length(); j++) {
JSONObject cc = productsArray.getJSONObject(j);
//------------------------------------------------------------------------
Log.e("audit",cc.getString("phone_name"));
String audit_id_str = cc.getString("audit_id");
int audit_id =Integer.parseInt(audit_id_str);
listview.setSelection(audit_id);
data.add(cc.getString("phone_name") +"\n\n"+cc.getString("audit_status") );
loadList(0);
btn_next.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
increment++;
loadList(increment);
CheckEnable();
}
});
btn_prev.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
increment--;
loadList(increment);
CheckEnable();
}
});
//------------------------------------------------------------------------
}
}
pdLoading.dismiss();
//CheckEnable();
}
} catch (JSONException e) {
e.printStackTrace();
}
}
private void loadList(int number)
{
ArrayList<String> sort = new ArrayList<String>();
title.setText("Page "+(number+1)+" of "+pageCount);
int start = number * NUM_ITEMS_PAGE;
for(int i=start;i<(start)+NUM_ITEMS_PAGE;i++)
{
if(i<data.size())
{
sort.add(data.get(i));
}
else
{
break;
}
}
sd = new ArrayAdapter<String>(Tblview.this,android.R.layout.simple_list_item_1,sort);
listview.setAdapter(sd);
}
private void CheckEnable()
{
if(increment+1 == pageCount)
{
btn_next.setEnabled(false);
btn_prev.setEnabled(true);
}
else if(increment == 0)
{
btn_prev.setEnabled(false);
btn_next.setEnabled(true);
}
else
{
btn_prev.setEnabled(true);
btn_next.setEnabled(true);
}
}
}
listview.setOnItemClickListener(new AdapterView.OnItemClickListener() {
#Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
int positon1 =position;
String a1 = Integer.toString(positon1);
Toast.makeText(getApplicationContext(),a1,Toast.LENGTH_SHORT).show();
}
});

If you are keeping count of page then you can add page number to item position.
That will give you unique number for each item.

Android HttpUrlConnection Url doesn't work on emulator

I am trying to get json object as string from this url http://digitalcollections.tcd.ie/home/getMeta.php?pid=MS4418_021. It doesn't work I get an error after downloadUrl function.
java.io.IOException: unexpected end of stream on Connection{digitalcollections.tcd.ie:80, proxy=DIRECT# hostAddress=134.226.115.12 cipherSuite=none protocol=http/1.1} (recycle count=0)
Although it does work for this androidhive url http://api.androidhive.info/volley/person_object.json.
I am new to httpconnection below is my download url function. Error seems to show in this line HttpURLConnection conn = (HttpURLConnection) url.openConnection(); In the debugger after that line conn.getInputStream() shows the IO exception and the cause java.io.EOFException: \n not found: size=0 content=...
// Given a string representation of a URL, sets up a connection and gets
// an input stream.
private InputStream downloadUrl(String urlString) throws IOException {
URL url = new URL(urlString);
HttpURLConnection conn = (HttpURLConnection) url.openConnection();
conn.setReadTimeout(20000 /* milliseconds */);
conn.setConnectTimeout(30000 /* milliseconds */);
conn.setRequestMethod("GET");
//conn.setDoInput(true);
// Starts the query
conn.connect();
InputStream stream = conn.getInputStream();
return stream;
}
Other functions.
// Uses AsyncTask to create a task away from the main UI thread. This task takes a
// URL string and uses it to create an HttpUrlConnection. Once the connection
// has been established, the AsyncTask downloads the contents of the webpage as
// an InputStream. Finally, the InputStream is converted into a string, which is
// displayed in the UI by the AsyncTask's onPostExecute method.
private class DownloadXMLTask extends AsyncTask<String, Void, List<Entry>> {
private String urlFront = "";
#Override
protected List<Entry> doInBackground(String... urls) {
// params comes from the execute() call: params[0] is the url.
try {
return loadJsonFromNetwork(urls[0]);
} catch (IOException e) {
Log.d(TAG, "Unable to retrieve web page. URL may be invalid.");
return null;
} catch (JSONException e) {
Log.d(TAG, "XMLPULLPARSER ERROR IN download json task function");
return null;
}
}
}
// onPostExecute displays the results of the AsyncTask.
#Override
protected void onPostExecute(List<Entry> result) {
//post execution stuff
}
}
Loading json and parser, the parser might not work haven't tested it yet.
private List<Entry> loadJsonFromNetwork(String urlString) throws IOException, JSONException {
InputStream stream = null;
int len = 20000; //max amount of characters to display in string
List<Entry> entries = new ArrayList<Entry>();
try {
stream = downloadUrl(urlString); //IOException
String jsonStr = readit(stream,len);
if(jsonStr.equals(null)){
Log.d(TAG, "ERROR json string returned null");
return entries;
}
JSONObject jsonObj = new JSONObject(jsonStr);
//Not sure if the json parser works yet haven't got that far
// Getting JSON Array node
identifier = jsonObj.getJSONArray("identifier");
// looping through All Contacts
for (int i = 0; i < identifier.length(); i++) {
JSONObject c = identifier.getJSONObject(i);
String id = c.getString("type");
if(id.equals("DRIS_FOLDER")) {
String folder = c.getString("$");
entries.add(new Entry(null,null,null,folder));
}
}
// Makes sure that the InputStream is closed after the app is
// finished using it.
//This is where IOexception is called and stream is null
} catch (IOException e) {
Log.d(TAG, "Unable to retrieve json web page. URL may be invalid."+ e.toString());
return entries;
}
finally {
if (stream != null) {
stream.close();
}
}
return entries;
}
I am running this on a Nexus_5_API_23 emulator.
Thanks in advance.
UPDATE:
Doesn't work on Nexus_5_API_23 emulator?? Although it works on a Samsung GT-ST7500 external phone. Want it to work for the emulator.

The problem was my antivirus/firewall on my computer. It was blocking my connection and that's why it was working on a external phone and not emulator. I disabled my antivirus/firewall and it worked. There is a list of network limitations here http://developer.android.com/tools/devices/emulator.html#networkinglimitations

I just tried that URL on my device and didn't get any errors. Here is the code I used.
An Interface to get back onto the UI Thread
public interface AsyncResponse<T> {
void onResponse(T response);
}
A generic AsyncTask that returns a String - Feel free to modify this to parse your JSON and return a List.
public class WebDownloadTask extends AsyncTask<String, Void, String> {
private AsyncResponse<String> callback;
public void setCallback(AsyncResponse<String> callback) {
this.callback = callback;
}
#Override
protected String doInBackground(String... params) {
String url = params[0];
return readFromUrl(url);
}
#Override
protected void onPostExecute(String s) {
super.onPostExecute(s);
if (callback != null) {
callback.onResponse(s);
} else {
Log.w(WebDownloadTask.class.getSimpleName(), "The response was ignored");
}
}
private String streamToString(InputStream is) throws IOException {
StringBuilder sb = new StringBuilder();
BufferedReader rd = new BufferedReader(new InputStreamReader(is));
String line;
while ((line = rd.readLine()) != null) {
sb.append(line);
}
return sb.toString();
}
private String readFromUrl(String myWebpage) {
String response = null;
HttpURLConnection urlConnection = null;
try {
URL url = new URL(myWebpage);
urlConnection = (HttpURLConnection) url.openConnection();
InputStream inputStream = urlConnection.getInputStream();
if (inputStream != null) {
response = streamToString(inputStream);
inputStream.close();
}
} catch (IOException e) {
e.printStackTrace();
} finally {
if (urlConnection != null) {
urlConnection.disconnect();
}
}
return response;
}
}
Section of my Activity to call the AsyncTask.
String url = "http://digitalcollections.tcd.ie/home/getMeta.php?pid=MS4418_021";
WebDownloadTask task = new WebDownloadTask();
task.setCallback(new AsyncResponse<String>() {
#Override
public void onResponse(String response) {
Toast.makeText(getApplicationContext(), response, Toast.LENGTH_SHORT).show();
}
});
task.execute(url);

Make sure to use https instead of http to avoid these kind of errors on your Android Emulators.
private static final String BASE_URL = "https://content.guardianapis.com/search?";