I just have a concern about AsycnTask. If i have one activity which starts a async task. Now that activity goes in background and new activity gets opened & visible to us.
So the async task opened by previous activity stops or it still keeps going in background or it pauses or stops ?
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What is the difference between Service, Async Task & Thread. If i am not wrong all of them are used to do some stuff in background. So, how to decide which to use and when?
View 2 Replies View RelatedI read somewhere (and have observed) that starting threads is slow. I always assumed that AsyncTask created and reused a single thread because it required being started inside the UI thread.The following (anonymized) code is called from a ListAdapter's getView method to load images asynchronously. It works well until the user moves the list quickly, and then it becomes "janky".final File imageFile = new File(getCacheDir().getPath() + "/img/" + p.image);image.setVisibility(View.GONE);view.findViewById(R.id.imageLoading).setVisibility(View.VISIBLE);
(new AsyncTask<Void, Void, Bitmap>() {
@Override
protected Bitmap doInBackground(Void... params) {
try {Bitmap image;
if (!imageFile.exists() || imageFile.length() == 0) {
image = BitmapFactory.decodeStream(new URL(
"http://example.com/images/"
+ p.image).openStream());
image.compress(Bitmap.CompressFormat.JPEG, 85,
new FileOutputStream(imageFile));
image.recycle();
}image = BitmapFactory.decodeFile(imageFile.getPath(),
bitmapOptions);
return image;
} catch (MalformedURLException ex) {
// TODO Auto-generated catch block
ex.printStackTrace();
return null;
} catch (IOException ex) {
// TODO Auto-generated catch block
ex.printStackTrace();
return null;
@Override
protected void onPostExecute(Bitmap image) {
if (view.getTag() != p) // The view was recycled.
return;
view.findViewById(R.id.imageLoading).setVisibility(
View.GONE);
view.findViewById(R.id.image)
.setVisibility(View.VISIBLE);
((ImageView) view.findViewById(R.id.image))
.setImageBitmap(image);
}}).execute();I'm thinking that a queue-based method would work better, but I'm wondering if there is one or if I should attempt to create my own implementation.
I have been searching for an answer for this for some time now. I have an async task that downloads the database needed for my app, while this is downloading my app cant do anything as all the data it references is in this file, i have the app waiting for the file to be downloaded but i am attempting to show a progress dialog so the user knows something is happening while they wait for this to happen.however nothing shows up i have also tried directly calling ProgressDialog.show in the pre execute and moving this to the calling activity with no luck.
View 2 Replies View RelatedI have a simple app and I'm using the AsyncTask to test out a background process, for clearness purposes I've opted to put my AsyncTask in a separate class rather than in an inner class, which where my problems begin, this is my AsyncTask. Code...
View 8 Replies View RelatedI've got an Android activity which grabs an RSS feed from a URL, and uses the SAX parser to stick each item from the XML into an array. This all works fine but, as expected, takes a bit of time, so I want to use AsyncActivity to do it in the background. The line items = parser.getItems() works fine - items being the arraylist containing each item from the XML. The problem I'm facing is that on starting the activity, the ProgressDialog which i create in onPreExecute() isn't displayed until after the doInBackground() method has finished. i.e. I get a black screen, a long pause, then a completely populated list with the items in. Why is this happening? Why isn't the UI drawing, the ProgressDialog showing, the parser getting the items and incrementally adding them to the list, then the ProgressDialog dismissing?
View 3 Replies View RelatedIm using a web service, so I want to use an async thread for the HTTP authentication request and another thread later to make additional service requests while my main thread runs.Would like to see a good example of how to do this and how to show busy messages somehow in main app. How does the main app know when the thread finished? And what if my thread encounters exceptions, how do I deal with that?HTTP requests are sent later, use the same cookies setup up by the first auth request, so will the later requests pick up the same cookies and just work?
View 2 Replies View RelatedIn the documentation, I read that it is not possible for executing 2 Async Tasks. If execute is called again, it should throw an exception.
The following is given under the heading of "Threading Rules", and i quote:
"The task can be executed only once (an exception will be thrown if a second execution is attempted.)"
I wish to understand the meaning of this statement.
Does this mean, that if i try and execute the same task twice (concurrently) when the first execution of the task was still going on...an exception will be thrown ? Will i need to wait for the completion of the first task, before i spawn a second task ?
A possible use case:
The user wishes to download a set of files. He clicks on the download button by providing the URL. When the first download is still going on, he wishes to download another file and provides another URL. Both these user actions are serviced by a DownloadTask, that extends the AysncTask.
If i wish to change this default behavior, is there a configuration option?
How do you create unit tests for an Android activity that starts async tasks in onCreate? I would like to test the result of these tasks.
View 1 Replies View RelatedI am developing a program that needs async socket. I am new to Android and Java. As I can see in the document, to write network program, I got Socket and SocketChannel, but it seems they are all sync socket, it means, I need an extra thread to call blocking read, write... and etc. Here comes the problem, my program is a chat room, the communicate is not linear, I have no idea when the server will send a message to me, if I read in that thread to wait message from server, but the user want to send message to server, the reading function blocked forever, if there is no incoming data, then the pending outgoing message will not be sent. That's why I need async socket. So my question is: How to write async socket under Android environment?
View 8 Replies View RelatedI've got the URL of a .png image, that needs to be downloaded and set as a source of an ImageView. I'm a beginner so far, so there are a few things I don't understand:
1) Where do I store the file?
2) How do I set it to the ImageView in java code?
3) How to correctly override the AsyncTask methods?
I have the following code...
CODE:.................
My mClient get method is a simple HttpClient execute with an output buffer to read the input stream, so it's very trivial. Everytime I execute this task UnknownHostException will be triggered which will in turn call onTaskError on my currect Activity, but I still get a RuntimeException, but I don't see why. Maybe it's because it's late and i've done about 12 hours of writing code so it's something simple I just can't see?
In my android application i am using a loading screen,processed by Async task.In do in background of this task i would like to display a alert whenever an upgraded version exist in the server.
Could you please let me know if there is any way that i can do it in android.
The code is.
CODE:.................
I'm writing an android program for adding task and deleting task in listview. I've add an onClickListener to the delete button so it can delete the task. However I was told I should not have the listener in the adapter violating mvc. how I can remove a task in my TaskListItem class. I got the method removeTask() in the adapter, but don't how I can use it in the TaskListItem class.
Code:
public TaskListItem(Context context, AttributeSet attrs) {
super(context, attrs);
mContext = context;
[code]...
I have read quite a good books & blogs about the Background work process in Android and updating the UI.
I have learned few way like using a Service with Intent, Using AsynTask, Using a Bind Service with a Intent and so..
What is the rule of thumb using this, i mean when to use what?
I am just learning to code in JAVA & Android.
Is there an app for choosing which apps you want to use that are already open or whatever. Or is there a button you can press to bring up a task list like you do with you blackberry when u hold the blackberry key and the list of open apps comes out.
View 5 Replies View RelatedAutomatic task killer, advanced task killer, or something else?
View 18 Replies View RelatedI've been using Task Panel X and Advanced Task manager to kill unneeded tasks and keep memory at a maximum.
Recently, every time I open Task Panel X and then revert back to Home screen I get the HTC logo and then a loading screen while the device sets itself. This happens even if I kill NO tasks.
So my solution was to uninstall Task Panel X and then use just Advanced Task Manager. All the sudden, same result.
Everytime I open either of these apps and then go back to home screen I get a BLACK SCREEN WITH HTC LOGO, THEN A BRIEF (10 SECONDS) LOADING SCREEN. THEN ALL IS NORMAL.
I know this was talked about before at different times but I still have 3 questions.
1. what is the difference between a task killer and a task manager?
2. should we be using one of these apps or not?
3. when you look at the awake time if it is like 70% or 80% and you aren't using the phone a bunch I take it that means something is running,how can you find what is running.and is the awake time that big of deal?
Looking for a guide on how to use task killer. I had task killer on and deleted it. I think I was killing tasks that were needed to keep certain functions running that I use frequently. If someone would take the time to help me understand how to use one, I think I would be much more successful with it.
example - text messaging just stopped ( werrent receiving them ) . Once I took task killer off, everything started working again.
Anyway, I just wanted for everyone to post their favorite Task Manager/Killer, and why, and if there are any flaws. I personally use Advanced Task Killer Free. It has a simple UI, and the when you select or unselect apps it remebers it so next time you launch the app you can only remove the apps that you usually do, and keep ones that always run. It doesn't slow down or break the system.
View 40 Replies View RelatedHas anyone used both. Ive heard that that Advanced Task Killer, still drains the battery. What about the Automatic Task Killer, which puts everything to sleep when not in use.
View 8 Replies View RelatedAdvanced Task Manager (ATMGR)
A tool to kill tasks,free memory,speed up phone.
Features
*Simpe,quick easy to use
*Ignore list to exclude apps
*Auto kill apps after screen off
*One click kill widget
*Quick uninstaller
*Send feedback in Settings
Want to install it ?
Google Market Search Keyword: ATMGR
APK Download:
http://www.infolife.mobi/install/mobi.infolife.taskmanager.apk
What is the best, in your opinion, task killer app?
View 10 Replies View RelatedShould i use a Task Manager or not. I was using one, however I read a forum that said "Do Not Use" the task manager, it drains the phone and the phone will take care of its self. I am confused. An I possibly corrupting files? My home screen is really slow, should I uninstall the task manager...
View 2 Replies View RelatedDoes anyone know whats up with a task manager for the g1? if its in the process of being made, if there is one to download somehow, is it possible to make? im sure this is part of the problem to the short battery life and it would help to be able to close apps so the phone wont freeze or blow up one...
View 6 Replies View RelatedIm looking a a task manager, im using task killer but every time i terminate everything i get an error, is there a program out there that autokill programs? like if not used for 2 minutes it terminates that program?
View 6 Replies View RelatedThere is the option to remind when the task is due and when it is over due. is there anyway to remind me "x" hours before the task is due?
View 3 Replies View RelatedI have a few questions about Task managers. At the moment I'm using ES Task manager. It works well and has a nice interface. My questions are.
A) Does the Android OS even need a task manager?Some say their not needed. The ones I've used do clear out tasks, frees up memory, and saves on the systems load.
B) What tasks should I clear?Lets say for example I killed voice mail at startup. Does this mean If someone called I would not receive voice mail until I reloaded the voice mail app, or would the phone see a voice mail is incoming and reload the program?
It's on the task bar right next to the sync icon, it's the shape of a cell phone. It wasn't there the past couple of days until this morning, weird.
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