Develop Reference

Call Async Webservice From For Loop

When I call a webservice from a for loop to insert/update data into MySQL using PHP only the last item gets inserted/updated because (i think) the for loop completes quicker than the webservice, how can I delay my for loop or achieve a webservice call for each item returned in the for loop one after another.
For Loop Code:
for (int i = 0; i < lv.getCount(); i++) {
view = lv.getAdapter().getView(i, lv.getChildAt(i), lv);
if (view != null) {
// Getting my views
tvItem = (TextView) view.findViewById(R.id.tvItem);
strItem = tvItem.getText().toString();
//Call AsyncTask
accessWebService();
}
}
Webservice:
private class Webservice extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... params) {
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost(params[0]);
try {
HttpResponse response = httpclient.execute(httppost);
jsonResult = inputStreamToString(response.getEntity().getContent()).toString();
}
catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
private StringBuilder inputStreamToString(InputStream is) {
String rLine = "";
StringBuilder answer = new StringBuilder();
BufferedReader rd = new BufferedReader(new InputStreamReader(is));
try {
while ((rLine = rd.readLine()) != null) {
answer.append(rLine);
}
}
catch (IOException e) {
}
return answer;
}
#Override
protected void onPostExecute(String result) {
try{
ld();
}catch (Exception e){
}
}
}// end async task
public void accessWebService() {
Webservice task = new Webservice();
//Update MySQL Using PHP
}

When you want to insert/update all data from for loop you must use callback like interfaces. Once you implement this it will wait for completing the process. Once completed it will call success or error method. Based on this you insert/update another record.
interface DataCallback {
fun onSuccess(result: Any)
fun onError(error: Any)
}
public void getCountries(new DataCallback(){
#Override
public void onSuccess(Object result){
// insert/update next record
}
#Override
public void onError(Object error){
// show error message
}
});
This is just example. You should convert it based on your need. Thanks.

d How can I use progress bar while fetching data from database?

I'm really bad at googling things I want so I decided to ask here. My question is is it possible to show a progress bar while fetching the data from the database? I'm using the typical code when fetching data(Pass value to php and the php will do the query and pass it again to android)
Edit(I have tried adding proggressdialog but the problem now is the loaded data will appear first before the progress dialog here's my AsyncTask code)
public class getClass extends AsyncTask<String, Void, String> {
public getClass()
{
pDialog = new ProgressDialog(getActivity());
}
URLConnection connection = null;
String command;
Context context;
String ip = new returnIP().getIpAddresss();
String link = "http://" + ip + "/android/getClass.php";//ip address/localhost
public URLConnection getConnection(String link) {
URL url = null;
try//retrieves link from string
{
url = new URL(link);
} catch (MalformedURLException e) {
e.printStackTrace();
}
URLConnection connection = null;
try//opens the url link provided from the "link" variable
{
connection = url.openConnection();
} catch (IOException e) {
e.printStackTrace();
}
connection.setDoOutput(true);
return connection;
}
public String getResult(URLConnection connection, String logs) {
//this is the functions that retrieves what the php file echoes
//everything that php throws, the phone receives
String result = "";
OutputStreamWriter wr = null;
try {
wr = new OutputStreamWriter(connection.getOutputStream());//compiles data to be sent to the receiver
} catch (IOException e) {
e.printStackTrace();
}
try {
wr.write(logs);
} catch (IOException e) {
e.printStackTrace();
}
try {
wr.flush();//clears the cache-esque thingy of the writer
} catch (IOException e) {
e.printStackTrace();
}
BufferedReader reader = null;
try {
reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
} catch (IOException e) {
e.printStackTrace();
}
StringBuilder sb = new StringBuilder();
String line = null;
//Read server response
try {
while ((line = reader.readLine()) != null) {
sb.append(line);
}
} catch (IOException e) {
e.printStackTrace();
}
result = sb.toString();
return result;
}
#Override
protected void onPreExecute() {
pDialog.setMessage("Loading...");
pDialog.show();
}
#Override
protected String doInBackground(String... arg0) {
// TODO Auto-generated method stub
String result = "";
//Toast.makeText(View_Classes.this, "ako n una", Toast.LENGTH_LONG).show();
try {
//first data sent is sent in command
command = (String) arg0[0];//it's in array, because everything you input here is placed in arrays
//Toast.makeText(View_Classes.this, "andtio n me", Toast.LENGTH_LONG).show();
if (command == "getCourses") {
connection = getConnection(link);
String logs = "";
logs = "&command=" + URLEncoder.encode(command, "UTF-8");
logs += "&username=" + URLEncoder.encode(username, "UTF-8");
result = getResult(connection, logs);
} else if (command == "getSections") {
connection = getConnection(link);
String logs = "";
logs = "&command=" + URLEncoder.encode(command, "UTF-8");
logs += "&username=" + URLEncoder.encode(username, "UTF-8");
logs += "&course=" + URLEncoder.encode(course, "UTF-8");
result = getResult(connection, logs);
}
return result;
} catch (Exception e) {
return result;
}
}
#Override
protected void onPostExecute(String result) {//this is going to be the next function to be done after the doInBackground function
// TODO Auto-generated method stub
if (pDialog.isShowing()) {
pDialog.dismiss();
}
if (result.equalsIgnoreCase(""))//if there's nothing to return, the text "No records" are going to be thrown
{
} else //Array adapter is needed, to be a place holder of values before passing to spinner
{
}
}
}

Have you tried using an AsyncTask?
You can show your progress bar on the preExecute method and then hide it on postExecute. You can do your querying inside the doInBackground method.

In addition to what #torque203 pointed, I would suggest you to check
http://developer.android.com/reference/android/os/AsyncTask.html#onProgressUpdate(Progress...)
this method was created for that purpose, showing progress to the user.

From developers docs:
private class DownloadFilesTask extends AsyncTask<URL, Integer, Long> {
#Override
protected void onPreExecute() {
//show progress bar here
}
protected Long doInBackground(URL... urls) {
//Pass value to PHP here
//get values from your PHP
}
protected void onPostExecute(Long result) {
//Here you are ready with your PHP value. Dismiss progress bar here.
}
}

public void onPreExecute() {
Progress Dialog pDialog = new ProgressDialog(this);
pDialog.setMessage("Loading...");
pDialog.show();
}
public void doInBackground() {
//do your JSON Coding
}
public void onPostExecute() {
Progress Dialog pDialog = new ProgressDialog(this);
pDialog.setMessage("Loading...");
pDialog.show();
}

public URLConnection getConnection(String link) {
URL url = null;
try//retrieves link from string
{
url = new URL(link);
} catch (MalformedURLException e) {
e.printStackTrace();
}
URLConnection connection = null;
try//opens the url link provided from the "link" variable
{
connection = url.openConnection();
} catch (IOException e) {
e.printStackTrace();
}
connection.setDoOutput(true);
return connection;
}
public String getResult(URLConnection connection, String logs) {
//this is the functions that retrieves what the php file echoes
//everything that php throws, the phone receives
String result = "";
OutputStreamWriter wr = null;
try {
wr = new OutputStreamWriter(connection.getOutputStream());//compiles data to be sent to the receiver
} catch (IOException e) {
e.printStackTrace();
}
try {
wr.write(logs);
} catch (IOException e) {
e.printStackTrace();
}
try {
wr.flush();//clears the cache-esque thingy of the writer
} catch (IOException e) {
e.printStackTrace();
}
BufferedReader reader = null;
try {
reader = new BufferedReader(new InputStreamReader(connection.getInputStream()));
} catch (IOException e) {
e.printStackTrace();
}
StringBuilder sb = new StringBuilder();
String line = null;
//Read server response
try {
while ((line = reader.readLine()) != null) {
sb.append(line);
}
} catch (IOException e) {
e.printStackTrace();
}
result = sb.toString();
return result;
}
public class getClass extends AsyncTask<String, Void, String> {
#Override
protected void onPreExecute() {
pDialog.setMessage("Loading...");
pDialog.show();
URLConnection connection = null;
String command;
Context context;
String ip = new returnIP().getIpAddresss();
String link = "http://" + ip + "/android/getClass.php";//ip address/localhost
}
#Override
protected String doInBackground(String... arg0) {
// TODO Auto-generated method stub
String result = "";
//Toast.makeText(View_Classes.this, "ako n una", Toast.LENGTH_LONG).show();
try {
//first data sent is sent in command
command = (String) arg0[0];//it's in array, because everything you input here is placed in arrays
//Toast.makeText(View_Classes.this, "andtio n me", Toast.LENGTH_LONG).show();
if (command == "getCourses") {
connection = getConnection(link);
String logs = "";
logs = "&command=" + URLEncoder.encode(command, "UTF-8");
logs += "&username=" + URLEncoder.encode(username, "UTF-8");
result = getResult(connection, logs);
} else if (command == "getSections") {
connection = getConnection(link);
String logs = "";
logs = "&command=" + URLEncoder.encode(command, "UTF-8");
logs += "&username=" + URLEncoder.encode(username, "UTF-8");
logs += "&course=" + URLEncoder.encode(course, "UTF-8");
result = getResult(connection, logs);
}
return result;
} catch (Exception e) {
return result;
}
}
#Override
protected void onPostExecute(String result) {//this is going to be the next function to be done after the doInBackground function
// TODO Auto-generated method stub
if (pDialog.isShowing()) {
pDialog.dismiss();
}
if (result.equalsIgnoreCase(""))//if there's nothing to return, the text "No records" are going to be thrown
{
} else //Array adapter is needed, to be a place holder of values before passing to spinner
{
}
}
}

Android- Not getting full response from HttpResponse

I am trying to get an HttpResponse in xml but Im not getting the whole response, what is courious is that if I loop the request the response ends in different parts but is never full.
I use the same code to request things from different Urls but I only get problems with one.
Here is the code of the AsyncTask:
public class NetworkTask extends AsyncTask<String, Void, HttpResponse> {
private AsyncTaskListener listener;
#Override
protected HttpResponse doInBackground(String... params) {
String link = params[0];
HttpGet request = new HttpGet(link);
AndroidHttpClient client = AndroidHttpClient.newInstance("Android");
try {
HttpResponse httpResponse = client.execute(request).;
return httpResponse;
} catch (IOException e) {
e.printStackTrace();
return null;
} finally {
client.close();
}
}
#Override
protected void onPostExecute(HttpResponse result) {
if (result != null){
try {
String sRes = EntityUtils.toString(result.getEntity());
listener.onNTCompleted(sRes);
} catch (IllegalStateException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
public NetworkTask(AsyncTaskListener listener){
this.listener=listener;
}
}

I am not sure if this helps you but you have a problem because EntityUtils.toString() reads data from the network stream, which should not be done on UI thread (onPostExecute). Try moving EntityUtils.toString() to doInBackground() first. This may not help solve your problem, but it is the right thing to do.

Retrieving a returned string from AsyncTask in Android

I want to retrieve the contents of this file and save that to a string.
I've tried using AsyncTask (based on this answer) and here is my class.
class RetreiveURLTask extends AsyncTask<Void, Void, String> {
private Exception exception = null;
public String ResultString = null;
protected String doInBackground(Void ... something) {
URL url;
try {
url = new URL("http://stream.lobant.net/ccfm.info");
HttpURLConnection urlConnection;
urlConnection = (HttpURLConnection) url.openConnection();
InputStream in = new BufferedInputStream(urlConnection.getInputStream());
String stream_url = IOUtils.toString(in, "UTF-8");
urlConnection.disconnect();
return stream_url;
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
} catch (Exception e) {
this.exception = e;
return null;
}
}
protected void onPostExecute(String stream_url) {
// TODO: check this.exception
// TODO: do something with the feed
if (this.exception != null)
this.exception.printStackTrace();
this.ResultString = stream_url;
}
}
I've tried using my AsyncTask class like this:
AsyncTask<Void, Void, String> stream_task = new RetreiveURLTask().execute();
String stream_url = stream_task.ResultString;
but ResultString isn't recognised.
I'm confused about how this all works. Since the AsyncTask runs in the background, even if I could assign my string to one of the public variables, there is no guarentee that it will be valid when I make the assignment. Even if I were to use some kind of getResult() function, I would need to know when to call it so that the code has completed executing.
So, how is this usually done?
(Also, is my http read code ok?)
My ability: I can code, but am new to android.

Use an interface
new RetreiveURLTask(ActivityName.this).execute();
In your asyctask
TheInterface listener;
In the constructor
public RetreiveURLTask (Context context)
{
listener = (TheInterface) context;
}
The interface
public interface TheInterface {
public void theMethod(String result);
}
In onPostExecute
if (listener != null)
{
listener.theMethod(stream_url);
}
In your activity class implement the interface
implements RetreiveURLTask.TheInterface
Implement the method
#Override
public void theMethod(String result) {
// update ui using result
}

// try this way
RetreiveURLTask task = new RetreiveURLTask();
task.execute();
private void response(String responseData){
// here you write your code which use responseData
}
class RetreiveURLTask extends AsyncTask<Void, Void, String> {
private Exception exception = null;
public String ResultString = null;
protected String doInBackground(Void ... something) {
URL url;
try {
url = new URL("http://stream.lobant.net/ccfm.info");
HttpURLConnection urlConnection;
urlConnection = (HttpURLConnection) url.openConnection();
InputStream in = new BufferedInputStream(urlConnection.getInputStream());
String stream_url = IOUtils.toString(in, "UTF-8");
urlConnection.disconnect();
return stream_url;
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
return null;
} catch (Exception e) {
this.exception = e;
return null;
}
}
protected void onPostExecute(String stream_url) {
// TODO: check this.exception
// TODO: check this.exception
// TODO: do something with the feed
super.onPostExecute(stream_url);
response(stream_url)
}
}

Make this
public String ResultString = "";
Global
Asynctask is not the main class here , that's the reason you get ResultString cannot be resolved or is not a field
make it a global variable then you'll be able to access it

The execution of the AsyncTask is started in the background, while the assignment is carried out immediately after the execution began. Therefore, the assignment is carried out before the execution of the AsyncTask is complete.
Your best bet is to conduct the assignment in the OnPostExecute() method.

Android Programming: HTTP GET REQUEST NOT WORKING

I require a GET reequest from my own server to be extracted from the web and then displayed on screen with a TextView.
I have set up a GET Request.
public class GetMethodEx {
public String getInternetData() throws Exception{
BufferedReader in = null;
String data = null;
try
{
HttpClient client = new DefaultHttpClient();
URI website = new URI("http://www.mybringback.com");
HttpGet request = new HttpGet();
request.setURI(website);
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 + nl);
}
in.close();
data = sb.toString();
return data;
} finally{
if (in != null){
try{
in.close();
return data;
}catch (Exception e){
e.printStackTrace();
}
}
}
}
}
And I have set up on my main thread to extract the information and display it in a text view.
public class Home extends Activity {
TextView httpStuff;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.httpexample);
httpStuff = (TextView) findViewById(R.id.tvhttp);
GetMethodEx test = new GetMethodEx();
String returned;
try {
returned = test.getInternetData();
httpStuff.setText(returned);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
}
However, the Textview doesnt seem to change?
Can someone help me please.

Change your code using AsyncTask if you want to make any network operation from Ui Thread as:
public class Home extends Activity {
TextView httpStuff;
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.httpexample);
httpStuff = (TextView) findViewById(R.id.tvhttp);
new LongOperation().execute("");
}
private class LongOperation extends AsyncTask<String, Void, String> {
#Override
protected String doInBackground(String... params) {
GetMethodEx test = new GetMethodEx();
String returned;
try {
returned = test.getInternetData();
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return returned;
}
#Override
protected void onPostExecute(String result) {
// Update Ui here
httpStuff.setText(result);
}
}
}

Android OS > = 3.0
does not allow NetworkRequest on main UI thread.
Use AsyncTask to call webrequest.