Develop Reference

Complete AsyncTask only when Firebase Task completes

How can I make an AsyncTask's doInBackground() only return when another async method completes?
On a high level, the Activity's purpose is to allow the user to upload a review. The review may also have images. Now in my code, I have two AsyncTasks: ImageCompressionTask and ImageUploadTask. Basically, once the user selects images to upload, ImageCompressionTask is executed for each image. In the onPostExecute() method of that task, ImageUploadTask is executed. The purpose of ImageUploadTask is to upload the compressed image and update the Firestore (database) with the download URL of the aforementioned uploaded image. Following is its code:
public class ImageUploadTask extends AsyncTask<byte[], Integer, Void> {
#Override
protected Void doInBackground(byte[]... bytes) {
StorageReference ref = App.getFireStorage().getReference();
ref = ref.child("review_images/" +
mDestinationId + "/" +
mExistingReview.getReviewId() + "/" +
mUploadProgressCount);
ref.putBytes(bytes[0]).addOnSuccessListener(taskSnapshot -> {
String url = taskSnapshot.getDownloadUrl().toString();
mExistingReview.getImages().add(url);
App.getFirestore().collection("reviews").document(mExistingReview.getReviewId()).set(mExistingReview);
mUploadProgressCount++;
});
return null;
}
}
However, the issue is that the doInBackground() returns prematurely. I understand WHY it happens (because the ref.putBytes() method runs asynchronously) but I want it to wait until ref.putBytes() finishes. How can I do that?

Can you please check it this way :
#Override
protected synchronized Void doInBackground(byte[]... bytes) {
StorageReference ref = App.getFireStorage().getReference();
ref = ref.child("review_images/" +
mDestinationId + "/" +
mExistingReview.getReviewId() + "/" +
mUploadProgressCount);
ref.putBytes(bytes[0]).addOnSuccessListener(taskSnapshot -> {
String url = taskSnapshot.getDownloadUrl().toString();
mExistingReview.getImages().add(url);
App.getFirestore().collection("reviews").document(mExistingReview.getReviewId()).set(mExistingReview);
mUploadProgressCount++;
});
return null;
}

i have solved this problem with ObservableInteger
is a listener that listen for values
private ObservableInteger mObsInt;
//Listener
mObsInt = new ObservableInteger();
mObsInt.set(0);
mObsInt.setOnIntegerChangeListener(new OnIntegerChangeListener()
{
#Override
public void onIntegerChanged(int newValue)
{
if (mObsInt.get()==1)
Log.e("Downloads"," mObsInt 1");
Log.e("Download1"," Finished first process ");
if (mObsInt.get()==2){
Log.e("Downloads"," mObsInt 2");
Log.e("Download2"," Finished second process ");
mProgressDialog.dismiss();
Intent mainIntent = new Intent().setClass(LoginActivity.this, Principal.class);
startActivity(mainIntent);
finish();
}
}
});
and then just do this (after a process has finished or an asynctask)
mObsInt.set(mObsInt.get()+1);
so it will count, if the first thing finish obsInt will be 1 , and when the second one finish, obsInt will be 2, so after obsInt == 2 , you can move on to the other activity or process you need
happy coding !

This can be accomplished with CountDownLatch:
public class ImageUploadTask extends AsyncTask<byte[], Integer, Void> {
#Override
protected Void doInBackground(byte[]... bytes) {
// Initialize CountDownLatch
final CountDownLatch signal = new CountDownLatch(1);
StorageReference ref = App.getFireStorage().getReference();
ref = ref.child("review_images/" +
mDestinationId + "/" +
mExistingReview.getReviewId() + "/" +
mUploadProgressCount);
ref.putBytes(bytes[0]).addOnSuccessListener(taskSnapshot -> {
String url = taskSnapshot.getDownloadUrl().toString();
mExistingReview.getImages().add(url);
App.getFirestore().collection("reviews").document(mExistingReview.getReviewId()).set(mExistingReview);
mUploadProgressCount++;
// Start count down
signal.countDown();
});
// Wait for putBytes to return and handle case if
// threads get interrupted.
// You can also specify a maximum time to wait before
// displaying error to user (ie Try Again)
try {
signal.await(30, TimeUnit.SECONDS);
} catch (InterruptedException e) {
e.printStackTrace();
}
return null;
}
}

how to synchronise 2 async threads / tasks

For my app I have to run two operations, both being asynchronous:
read from a file ( I use this file to simulate reading from a data bus ) - async operation because I don't know "when" arrive a new
message/character on the bus. I search for a specific sequence
character, eg frame start_bytes = "xx" and the 4 following bytes are
"the data" I wait for.
read / update data to Firebase, depending on the "data" read from file - async operation due to addValueEventListener use.
I'm thinking a semaphore/mutex mechanism or a simple boolean flag that one task signal to the other one that a new data must be saved/updated to Firebase.
How can I synchronize these two operations ( by embedding them in a Task / AsyncTask / Thread)?
I ran a search for these topics but I found examples related to UI, ProgressBars and so on .. not really suited/useful to my situation.
read / update data in Firebase
myRefDevices.addValueEventListener(new ValueEventListener() {
// addValueEventListener
// This method is called once with the initial value and again
// whenever data at this location is updated.
#Override
public void onDataChange(DataSnapshot dataSnapshot) {
boolean bChildFound = false;
DatabaseReference dbrefChildFound;
final CDeviceStatus obj_new = new CDeviceStatus();
for( DataSnapshot val : dataSnapshot.getChildren() )
{
if( val.getKey().contentEquals(MAC_ADDRESS[ iIterator ]) )
{
bChildFound = true;
dbrefChildFound = val.getRef();
obj_new.setiAvailable_A( val.getValue( CDeviceStatus.class ).getiAvailable_A() + 1 );
obj_new.setsID(val.getValue( CDeviceStatus.class).getsID() );
dbrefChildFound.setValue(obj_new);
}
}
if(!bChildFound)
{
Log.d("child=" + MAC_ADDRESS[ iIterator ], "not found");
}
if(++iIterator == 16)
{
iIterator = 0;
}
}
#Override
public void onCancelled(DatabaseError databaseError) {
}
});
read from file :
try {
// open input stream text file for reading
Resources res = getResources();
InputStream instream = res.openRawResource( R.raw.simulated_bus );
// we convert it to bufferred input stream
BufferedInputStream bistreamSimulatedBus = new BufferedInputStream(instream);
try{
// if we want to stop reading from the file / simulated bus for whatever reason..
boolean bStayInLoop = true;
while ((bistreamSimulatedBus.available() > 0) && bStayInLoop)
{
try {
// throw new InterruptedException();
char c = (char) bistreamSimulatedBus.read();
if( COUNT_CHARACTERS_NEWLINE )
{
if ( '\n' == c ){
// we can count how much NewLine character we have
//iNL_Counter++;
}
}
...
}
catch ( InterruptedException e ) {
throw new RuntimeException( e );
}
}
} catch (IOException e) {
throw new RuntimeException( e );
}
finally {
// release any resource associated with streams
if ( null != instream ) {
instream.close();
}
if ( null != bistreamSimulatedBus ) {
bistreamSimulatedBus.close();
}
}
}
catch (Exception e) {
throw new RuntimeException( e );
}
Thank you.

Let us break the solution like this:
The basics
You have two operations : o1 and o2. You want the second operation to execute as soon as the first one has completed.
It clearly appears to me that you need an event-driven solution here.
Approach
Using the concept of Publisher/Subscriber design pattern, you can make the Initiator of o1 be the Publisher of an event. Then, when this particular operation o1 is completed, let the class (activity, fragment, service) notify the other class which we will call Subscriber.
Code
Add the following line to your build.gradle (app-level):
compile 'org.greenrobot:eventbus:3.0.0'
Then, simply create a simple Plain Old Java Object (POJO) that represents your event.
public class RequestCompletedEvent{ // add constructor and anything you want}
Next, to Publish the event, you simply call the post(POJO instance) like this:
EventBus.getDefault().post(new RequestCompletedEvent(true));
Then, finally, in the Subscriber class, simply listen for notifications by adding the following lines of code:
#Override
public void onStart() {
super.onStart();
EventBus.getDefault().register(this);
}
#Override
public void onStop() {
super.onStop();
EventBus.getDefault().unregister(this);
}
Then still within the same class, use the Subscribe annotation to catch any signals:
#Subscribe
public void onEvent(RequestCompletedEvent event) {
/* Do something */
//trigger the second operation here;
startOperationTwo();
}
Summary
It would help to note here that the easiest way to pull this off is to use an async task (AsyncTask sub class) to read your files, then when successfully done, inside onPostExecute(), you can notify the Subscriber to initiate the next operation.
I hope this helps; and good luck! Let me know if you need further assistance!

Return multiple values from AsyncTask/doInBackground and use it in other method

This is the method which I use to get values.
#Override
protected Void doInBackground(String... params) {
try {
Intent intent = getIntent();
String dvlaNumFin = intent.getStringExtra("dvlaNumber");
final TextView outputView = (TextView) findViewById(R.id.showOutput);
final URL url = new URL("https://dvlasearch.appspot.com/DvlaSearch?licencePlate="+dvlaNumFin+"&apikey=");
HttpURLConnection connection = (HttpURLConnection) url.openConnection();
connection.setRequestMethod("GET");
connection.setRequestProperty("USER-AGENT", "Mozilla/5.0");
connection.setRequestProperty("ACCEPT-LANGUAGE", "en-US,en;0.5");
final StringBuilder output = new StringBuilder(String.valueOf(url));
BufferedReader br = new BufferedReader(new InputStreamReader(connection.getInputStream()));
String line = "";
StringBuilder responseOutput = new StringBuilder();
System.out.println("output===============" + br);
while ((line = br.readLine()) != null) {
responseOutput.append(line);
}
br.close();
HandleJSON obj = new HandleJSON("");
obj.readAndParseJSON(responseOutput.toString());
output.append(System.getProperty("line.separator") + "\n" + System.getProperty("line.separator") + "Make : " + obj.getMake() + "\nModel : " + obj.getModel());
output.append("\nSix Month Rate : " + obj.getSixMonthRate() + "\nTwelve Month Rate : " + obj.getTwelveMonthRate() + "\nDate of First Registration : " + obj.getDateofFirstRegistrationegistration());
output.append("\nYear of Manufacture : " + obj.getYearOfManufacture() + "\nCylinder Capacity : " + obj.getCylinderCapacity() + "\nCO2 Emmissions : " + obj.getCo2Emissions());
output.append("\nVIN number : " + obj.getVin() + "\nTransmission type : " + obj.getTransmission());
DVLAresult.this.runOnUiThread(new Runnable() {
#Override
public void run() {
outputView.setText(output);
progress.dismiss();
}
});
} catch (MalformedURLException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return null;
}
I would like to use obj.getMake() and so on, the values from JSON. But do not understand how to do it, or return it. I know should be return value, or by using final.

Nice and simple. Make your AsyncTask return a value:
public class TestClass extends AsyncTask<Void, Void, String>{
#Override
protected String doInBackground(String... params) {
//rest of code
return output.toString();
}
}
Now all you have to do is call .get() method after calling .execute()
TestClass tc = new TestClass();
tc.execute();
String output = tc.get();
Very Very Important Note
By calling .get() right after .execute() your UI thread will be blocked until the AsyncTask is done. This is counter intuitive to the purpose of AsyncTask. One of the solutions to this problem is adding a callback interface to the AsyncTask which will be called upon finishing and call the .get() method in the implementation of that interface. For an example on how to design a callback interface see here.

FOG
Simply implement onPostExecute inside your AsyncTask class :)
for example :
#Override
protected void onPostExecute(String makeValue) {
// remember this method gets called on main thread
letsCallFogsMethod(makeValue); //call your method and pass the make value here :)
}
Thats it buddy :)
Now how come this onPostExecute is getting any value???
You have to return it from doInBackground method dude :)
like
#Override
protected String doInBackground(String... params) {
//after all bra bla simply say
return obj.getMake();
}
Do you notice any change in your doInBackground signature buddy?? Yeah I changed from Void to String :)
By writing String you are informing that when you are done executing doInBackground you will return a string to onPostExecute :)
So if I write as it is in the answer will it work ?? Nope.
Given that you have specified Void in your doInBackground your Async task signature might look something like
private class FogsAsyncTask extends AsyncTask<bla,blah,Void> {
Can you see the last Void??? :) But now you have chnaged doInBackground isn't it so update the AsyncTask signature as well :)
private class FogsAsyncTask extends AsyncTask<bla,blah,String> {
Now it should work fine :) Happy coding buddy :) Hope my answer helped you :)

You can get the output on onPostExecute method just override the method and get the output on it

AsyncTask has three (main) methods, onPreExecute, doInBackground and onPostExecute. Only doInBackGround runs on a background thread, the other two run on the UI thread. (there is also onProgressUpdate but I will skip it here)
In your case, return anything you want in doInBackground method. That return value will be the input param for onPostExecute. There you can call any other (reachable) method you want. Mind that you'd be running inside the UI thread at that time.

is it safe to use ThreadPoolExecutor inside AsyncTask doInBackground

I have to download a Json with a list of files, and then parallel download the files in the list. I would like to update periodically the ProgressDialog, so I implemented in this way
I create and show the dialog
I start an AsyncTask
onProgressUpdate receives 2 Integers, current progress and max progress, and updates the progress bar
doInBackground
downloads the json file and obtains the list of files to download
creates a ThreadPoolExecutor (tpe), with a LinkedBlockingQueue<Runnable>
submit a runnable for each file, that download the file to disk using Apache commons-io FileUtils.copyURLToFile
exec shutdown
in a while cycle. tpe.awaitTermination(1, TimeUnit.SECONDS) invokes periodically publishProgress( (int) tpe.getCompletedTaskCount(), tot), to update the progress bar
onPostExecute hides and dismisses the progres bar, and manages the files downloades
is there any problem in using ThreadPoolExecutor inside an AsynTask?
I am discussing with a colleague who claims that there could be problems in the threads management, that could deadlock, and that might give us problems on future versions
that's the code
public static void syncFiles(...)
{
PowerManager pm = (PowerManager) context.getSystemService(Context.POWER_SERVICE);
sWakelock = pm.newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, TAG);
sWakelock.acquire();
sProgress = new ProgressDialog(context);
sProgress.setCancelable(false);
sProgress.setTitle("MyTitle");
sProgress.setMessage("Sincronizzazione in corso");
sProgress.setProgressStyle(ProgressDialog.STYLE_HORIZONTAL);
sProgress.setIndeterminate(false);
sProgress.show();
sCurrentTask = new AsyncTask<Void, Integer, Manifest>()
{
#Override
protected void onCancelled()
{
if ((sProgress != null) && sProgress.isShowing())
sProgress.dismiss();
if ((sWakelock != null) && sWakelock.isHeld())
sWakelock.release();
};
#Override
protected Manifest doInBackground(Void... params)
{
ArrayList files = getFiles(....)// download the jsonfile, and return the list of files
final String baseurl = ... // get the remote base url
final String baselocal = ... //get the local base path ;
int tot = m.size();
publishProgress(0, tot);
final int MAX_THREADS = Runtime.getRuntime().availableProcessors(); * 4;
ThreadPoolExecutor tpe = new ThreadPoolExecutor(
MAX_THREADS,
MAX_THREADS,
1,
TimeUnit.MINUTES,
new LinkedBlockingQueue<Runnable>()
);
for (final String s: files)
{
tpe.submit(new Runnable()
{
#Override
public void run()
{
try
{
URL remoteUrl = new URL(baseurl + s);
File localUrl = new File(baselocal, s);
FileUtils.copyURLToFile(remoteUrl, localUrl, 60000, 60000);
Log.w(TAG, "Downloaded " + localUrl.getAbsolutePath() + " in " + remoteUrl);
} catch (Exception e)
{
e.printStackTrace();
Log.e(TAG, "download error " + e);
// error management logic
}
}
});
}
tpe.shutdown();
int num = 0;
publishProgress(num, tot);
try
{
while (!tpe.awaitTermination(1, TimeUnit.SECONDS))
{
int n = (int) tpe.getCompletedTaskCount();
Log.w(TAG, "COUTN: " + n + "/" + tot);
if (n != num)
{
num = n;
publishProgress(num, tot);
}
}
} catch (InterruptedException e)
{
// TODO Auto-generated catch block
e.printStackTrace();
}
return m;
}
protected void onProgressUpdate(Integer... prog)
{
if (sProgress.getMax() != prog[1]) {
sProgress.setMax(prog[1]);
}
sProgress.setProgress(prog[0]);
}
#Override
protected void onPostExecute(Manifest result)
{
sWakelock.release();
sProgress.hide();
sProgress.dismiss();
// manage results
}
}.execute();
}

If you'll checkout the implementation of AsyncTask then youi can find that AsyncTask itself has ThreadPool so it will start the task on separate thread. Acutually when we can the .execute() to start the background task this method is typically used with THREAD_POOL_EXECUTOR to allow multiple tasks to run in parallel on a pool of threads managed by AsyncTask. So why you need to implement another.
Update
Read about executeOnExecutor in this may be this can help you... It clearly says that if you are allowing multiple tasks to run in parallel from a thread pool is generally not what one wants, because the order of their operation is not defined....but here you want to download the files so I don't think the order is important so in my view you can use it and it'll not create any issue.

Return data from AsyncTask Android

I tried to refer similar question on SO, but didn't got any help.
In my android app, I'm planning to implement Recent Quote the user has visited i.e. similar to recently visited pages on web.
Following are the steps I'm following:
1.) Whenever user opens any company view, fetch the company symbols from database
2.) Then store the current symbol along with dateTime in database.
3.) For all symbols fetched from database, Fetch their current value and %Change and display Company name, current value and %Change in a list.
The problem arises in the ASyncTask class as postExecute method doesn't allow it's return type to be any other than void.
Am I doing anything wrong?
Any help will be life saver !!!
String[] rsym,rcmp,rchg;
rdbM = new RecentDBManager(CompanyView.this);
try {
Calendar date1 = Calendar.getInstance();
SimpleDateFormat dateformatter = new SimpleDateFormat(
"dd/MM/yyyy HH:mm:ss");
String currentdate = dateformatter.format(date1.getTime());
rdbM.openDB();
//STEP 1
rsym = rdbM.getRecent_sym();
//STEP 2
rdbM.setData(currentsymbol, currentdate);
rdbM.closeDB();
} catch (Exception e) {
throw new Error(" *** ERROR in DB Access *** "+ e.toString());
}
//STEP 3
for(int i=0;i<rsym.length;i++)
{
DownloadRecentQuote quotetask = new DownloadRecentQuote();
recentquotetask
.execute(new String[] { "http://abc.com/stockquote.aspx?id="
+ rsym[i] });
//CURRENT VALUE and %CHANGE which should be returned from ASyncTask class
rcmp[i]=valuearr[0];
rchg[i]=valuearr[1];
}
list1 = new ArrayList<HashMap<String, String>>();
HashMap<String, String> addList1;
for (int i = 0; i < limit; i++)
{
addList1 = new HashMap<String, String>();
addList1.put(RecentSym_COLUMN, rsym[i]);
addList1.put(RecentCMP_COLUMN, rcmp[i]);
addList1.put(RecentChg_COLUMN, rchg[i]);
list1.add(addList1);
RecentAdapter adapter1 = new RecentAdapter(
CompanyView.this, CompanyView.this, list1);
listrecent.setAdapter(adapter1);
}
private class DownloadRecentQuote extends AsyncTask<String, Void, String> {
/* Fetching data for RecentQuote information */
#Override
protected String doInBackground(String... urls) {
String response = "";
for (String url : urls) {
DefaultHttpClient client = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(url);
try {
HttpResponse execute = client.execute(httpGet);
InputStream content = execute.getEntity().getContent();
BufferedReader buffer = new BufferedReader(
new InputStreamReader(content));
String s = "";
while ((s = buffer.readLine()) != null) {
response += s;
}
} catch (Exception e) {
e.printStackTrace();
}
}
return response;
}
#Override
protected void onPostExecute(String result) {
arr1 = result.split("#");
if (arr1[0].length() != 0) {
if (arr1[0].equals("1")) {
arr = arr1[1].split(";");
//RETURN 2 STRINGS
String valuearr[];
valuearr[0] = arr[3];
valuearr[1] = arr[6].concat("%");
//return valuearr;
}
}
}

postExecute() can't return a value because who or what would it return to? Your original method that invoked the AsyncTask is gone because your AsyncTask is running in the background. It's asynchronous meaning when AsyncTask.execute() returns it's still running in the background, and hence postExecute() can't return a value because there's nothing to return it to.
Instead your AsyncTask needs a reference back to your Activity or some other object so it can post your values back to it. In your code the lines after you call execute() can't be there because your task hasn't finished. Instead you should create a method called updateSymbol( currentPrice, percentChange), move all that code below execute() in there, and in your AsyncTask you should pass a reference to the Activity. Then call updateSymbol( currentPrice, percentChange ) from the onPostExecute() method.
But, be careful if you have a reference back to an Activity it can be destroyed while your doInBackground() is running, and when postExecute() runs it should just drop the results or not attempt to update the UI. For example, the user rotates their phone causing the Activity to be destroyed. I find it best to hold a reference to the AsyncTask in the activity so it can cancel() it if the Activity is destroyed. You can call AsyncTask.cancel() then check if your task was canceled like:
public void postExecute( String result ) {
if( !isCanceled() ) {
// do your updating here
activity.setSymbol( result );
}
}
It's really easy to create a base class for all Activities so you can easily keep track of AsyncTasks running:
public class BaseActivity extends Activity {
List<AsyncTask> runningTasks;
public void onStop() {
for( AsyncTask task : runningTasks ) {
task.cancel(true);
}
}
public AsyncTask start( AsyncTask task ) {
runningTasks.add( task );
return task;
}
public void done( AsyncTask task ) {
runningTasks.remove( task );
}
}
Some quick pointers. You don't need execute( new String[] { "blah" + blah } ). Varargs in Java allow you to do this. execute( "blah" + blah ). You also are catching exceptions and continuing without really handling them. It will be hard when something really happens because your app catches them, and just continues as if nothing happened. If you get an error you might want to provide some feedback to the user and stop trying to execute that process. Stop, show an error to the user, and let them do the next thing. Move the catch blocks to the bottom of the methods.

Essentially, AsyncTask.onPostExecute() is where you do whatever you want to do after AsyncTask's doInBackground() is executed and the execution result gets returned. This should be considered the best practice.
When AsyncTask().execute() is called from the UI thread (note that this method must be called from the UI thread), the Android framework creates a worker thread and starts running whatever you wrote in AsyncTask.doInBackground() on this worker thread. At this point (after calling new AsyncTask().execute()), the UI thread continues to execute code after new AsyncTask().execute(). So now during run time, you have two threads (UI and worker thread) both running simultaneously.
But where and when does the AsyncTask execution result get returned from the worker thread back to the UI thread?
The point where your worker thread (doInBackground()) finishes and returns to the UI thread is AysncTask.onPostExecute(). This method is guaranteed to be called by the framework on the UI thread as soon as AsyncTask finishes. In other words, we don't care where and when AsyncTask.onPostExecute() gets called at run time, we just need to guarantee it will be called ultimately at some stage in the future. This is the reason why this method does not return an execution result - instead, it requires that the execution result gets passed in as the only method parameter from doInBackground().
In addition, the Android API provides a way to return an AsyncTask execution result at coding time, AsyncTask.get():
MyAsyncTask myAsyncTask = new MyAsyncTask();
// This must be called from the UI thread:
myAsyncTask.execute();
// Calling this will block UI thread execution:
ExecutionResult result = myAsyncTask.get();
Bear in mind that AsyncTask.get() will block the calling thread's execution, and you will probably get an ANR exception if you call it on the UI thread. This is the payload of using AsyncTask.get(), by calling it on the UI thread, you are actually making your AsyncTask (worker thread) run synchronously with UI thread (by making UI thread wait). To sum up, this is doable but not recommended.

Just for future reference, because this post is a little old:
I have created an Activity class which has an onStart() method and a separate class for the AsyncTask. Based on my test, after the doInbackground() method the result will be sent to the activity first and after that onPostExecute() will run. This is because based off of logcat, I have my first response data (sent by server) first, then this response will show again from the activity and the last the message in onPostExecute() will show.
Code for the activity:
#Override
protected void onStart() {
super.onStart();
String str = "***";
if(isConnectedToInternet()){
myAsyncTask.execute();
try {
if(myAsyncTask.get())
str = myAsyncTask.getResponseMsg();
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
} catch (CancellationException e) {
e.printStackTrace();
}
}
Log.i("Data returned by server2:", str);
}
AsyncTask code:
public class MyAsyncTask extends AsyncTask<Void, Void, Boolean> {
private URL url;
private HttpURLConnection conn;
private String strResponseMsg;
public MyAsyncTask(String url) throws MalformedURLException{
this.url = new URL(url);
}
#Override
protected void onPreExecute() {
Log.i("Inside AsyncTask", "myAsyncTask is abut to start...");
}
#Override
protected Boolean doInBackground(Void... params) {
boolean status = false;
try {
conn = (HttpURLConnection) url.openConnection();
conn.setConnectTimeout(Manager.ConnTimeout);
conn.setReadTimeout(Manager.ReadTimeout);
int responseCode = conn.getResponseCode();
Log.i("Connection oppened", "Response code is:" + responseCode);
if (responseCode == HttpURLConnection.HTTP_OK) {
BufferedReader in = new BufferedReader(new InputStreamReader(conn.getInputStream()));
if (in != null) {
StringBuilder strBuilder = new StringBuilder();
// Read character by character
int ch = 0;
while ((ch = in.read()) != -1)
strBuilder.append((char) ch);
// Showing returned message
strResponseMsg = strBuilder.toString();
Log.i("Data returned by server:", strResponseMsg);
status = true;
}
in.close();
}
} catch (IOException e) {
e.printStackTrace();
}
return status;
}
#Override
protected void onPostExecute(Boolean result) {
Log.i("Inside AsyncTask", "myAsyncTask finished its task. Returning data to caller...");
}
public String getResponseMsg(){
return strResponseMsg;
}
}