Android :: Modifying Adapter Content From Background Thread

Sep 14, 2010

I've read up quite a bit on the exception thrown while using BaseAdapter, but i can't seem to find an alternative solution: Make sure the content of your adapter is not modified from a background thread. What i want to achieve is to keep a copy of a message queue in memory, and use this message queue to populate the BaseAdapter for my ListView. The reason im doing this is that the message queue will keep getting messages from a socket even when the ListView is not currently present (for example a chat window).

The problem comes when i have the Activity with the ListView in foreground, BaseAdapter binded to the message queue's data, and a message comes in the socket. Adding the new message into the queue will throw the exception mentioned above. Unless i pre-populate my BaseAdapter with the message queue (as in the BaseAdapter having its own message queue) and updating both of them when a new message come in, i can't really find a way around this issue. I don't really want to double up the effort on keeping those 2 queues up-to-date like this, surely there is a better way of doing this? Send broadcasts around doesn't work either because of the potential delay in the adapter serving a scroll and the notifyDataSetChanged call is made.

Android :: Modifying adapter content from background thread


Android :: Moving Cursor Adapter Cursor Creation To Background Thread

Mar 29, 2010

The structure of some of my activities is a simple ListView with a custom CursorAdapter. The cursor is created in onCreate() on the activity from a SQLite database. The problem is that querying the SQLite database can be quite slow at times with lots of data (and let's assume I've already optimized the sql query as much as possible). Because it occurs in onCreate() on the UI thread, I get ugly black screens when opening the activity, which sometimes turn into ANRs, on a slow phone like the G1. I want to load the cursor in a background and show "Loading.." on screen while doing so. I saw AsyncQueryHandler used extensively in the framework, but this seems a solution geared more towards Content Providers and not application-local SQLite databases. I then thought of trying to load the cursor in a background thread, but realize that this might be problematic, as the CursorAdapter should be instantiated in onCreate() and should take a cursor as a parameter. The latest thought I had was to instantiate an empty MatrixCursor in onCreate() and pass that to the cursor adapter, while kicking off a thread/TimerTask to query the database. Then, on database cursor load, call cursorAdapter.change Cursor to the properly filled cursor. This doesn't seem very elegant and seems quite wasteful, however.

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Android :: ListActivity Design / Changing Content Of List Adapter

May 31, 2010

I would like to write a rather simple content application which displays a list of textual items (along with a small pic).I have a standard menu in which each menu item represents a different category of textual items (news, sports, leisure etc.).Pressing a menu item will display a list of textual items of this category.Now, having a separate ListActivity for each category seems like an overkill (or does it?)
Naturally, it makes much more sense to use one ListActivity and replace the data of its adapter when each category is loaded.My concern is when "back" is pressed. The adapter is loaded with items of the current category and now I need to display list of the previous category (and enable clicking on list items too)
Since I have only one activity - I thought of backup and load mechanism in onPause() and onResume() functions as well as making some distinction whether these function are invoked as a result of a "new" event (menu item selected) or by a "back" press.This seems very cumbersome for such a trivial usage.Am I missing something here?

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Delay Showing Content In Fragment Pager Adapter

Jul 3, 2013

I'm using FragmentPagerAdapter has 5 tabs. In tab number 3 I'm showing data in listview from web service and it showing successfully. When I swipe to tab 2, 4 and return to tab 3, the data is still showing in listview. If I swipe to tab 1, 5 and return to tab 3, the data delay to appearing some seconds.

* In TabFragment class I'm calling AsyncTask class called "GetTopNotifications". like this coding:

[HIGH]
public static class TabFragment extends Fragment
{
public static final String ARG_OBJECT = "object";
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)

[Code]...

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Android :: Run Background Thread In Application?

May 21, 2010

I need to run a background thread in my application. Could you please share the best practices where to initiate the thread so that keeps running irrespective of the Activity is being shown and things to consider. The purpose of this background thread is to fire transactions from the Simulator to the server and get the response back from the host.

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Android :: CursorAdapter Run In Background Thread?

Sep 24, 2010

Does the CursorAdapter run on a background thread and posts updates via the UI looper thread? If not what is the best pattern to load data asynchronously from a ContentProvider?

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Android :: Avoid Background Thread Been Killed?

Mar 1, 2009

As is mentioned above,What i'm trying is to protect a sub- thread,and keep it going on as long as the App that starts it is still alive.In other words,If the system need more resources,Let it kill both the App main thread and the sub-thread started from it,Instead of just kill the sub-thread.Is there any way i can do this ?? And another question here,The android system seems to be "rude",As it killed my thread without telling me,even in the logs,Is this the case?

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Android :: Leave Running Thread In Background?

Feb 17, 2010

is there any way to leave a thread in background when i close the app in android? I read about a Service but implementing it is too much than i need.

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Android :: PopUp Dialog From Background Thread

Jun 22, 2009

I need to popup dialog to be showed when i get a message from differnt thread but the dialog should be not dependent on Activity i.e, it should display the dialog wherever the screen focus is .can it be done ..because the dialog is handled per Activity ,i thought of using service but again it would be one more thread added so want to avoid that.

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Android :: Raise AlertDialog From Background Thread?

Nov 25, 2009

In my activity there's some stuff going on in a background thread, which gets started in Activity_1. The processing of the background thread takes a while and I want to notify the user when it's completed via an AlertDialog. However, the user might have changed to Activity_2 or Activity_3 in the meantime and I would like to pop up the AlertDialog always in the current Activity.

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Android :: Create View With Background That Wraps Up All Content?

Mar 5, 2009

I'm trying to create a listview containing conversations in chat bubbles, and each chat bubbles are rows in the list view. So what I have is an avatar on the left, and a chat bubble on the right. Then in the chat bubble, I have a textview for name, a textview for content, and a textview for time. The problem is, I cannot adjust the height of the chat bubble such that the bottom edge is just below the textview for time. In the chatBubble, I have this line that does not work android:layout_alignBottom="@+id/timeLabel" because timeLabel is a textview created after chatBubble. If I place chatBubble tags right below timeLabel, the height of chatBubble will be just right because lf the layout_alignBottom, but chatBubble covers all the text created before it.

Is there a way I can create the chatBubble last, and bring the view to the background? Or is there a better way to do this?....................

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Android :: Create Thread In Background For Playing Sound?

Nov 4, 2010

how create thread in background for playing sound?

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Android :: How To Stop A Background Thread On Keyboard Flip?

Oct 24, 2009

How can I stop a background thread on keyboard flip in android?

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Android :: How To Update View Object On Main Thread By Background?

Mar 3, 2009

My purpose is very simple : each 1second, I want to redraw an object on different place on background. I do not know where my error on this code below. Here is my code:
public class My_View extends View{ private Bitmap mBackground_img;
private Drawable mMoveObject; private int mObjectw,mObjecth; private int Dx,Dy;
private Handler myHandler = new Handler(); private long lasttime;
public My_View(Context context,AttributeSet ats,int ds) {
super(context,ats,ds); init(context);
} public My_View(Context context,AttributeSet ats) { super(context,ats);
init(context); } public My_View(Context context) { super(context);
init(context); } public void change() { invalidate();
} private void init(Context context) {
Resources res = context.getResources();
mMoveObject = res.getDrawable (R.drawable.lander_firing);
mBackground_img = BitmapFactory.decodeResource(res, R.drawable.my_pic);
mObjectw = mMoveObject.getIntrinsicWidth();
mObjecth = mMoveObject.getIntrinsicHeight();
Dx = Dy = 0; lasttime = System.currentTimeMillis() + 1000;
Thread mthread = new Thread(null,doBackground,"Background");
mthread.start(); } private Runnable doBackground = new Runnable() {
public void run() { long now = System.currentTimeMillis();
if(lasttime < now ) { Dx = Dx + 10; Dy = Dy + 10;
lasttime = now + 1000; myHandler.post(change_view);
} } }; private Runnable change_view = new Runnable() {
public void run() { change();
} };
@Override public void onDraw(Canvas canvas) {
canvas.drawBitmap(mBackground_img,0 ,0 , null);
mMoveObject.setBounds(Dx, Dy, Dx+mObjectw, Dy+mObjecth);
mMoveObject.draw(canvas);
} }

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Android :: Game Doesn't Work Due To Thread Background Processes

Mar 8, 2010

I have written a very simple game with some simple animations, but I've noticed that when the phone checks email, or several other apps are running, the animations that update in my thread start behaving slowly or choppy. This is a problem as the game mechanic requires some careful timing of your screen touches based on the animations. So if it starts behaving erratically, the game doesn't really work well - and isn't much fun.
Is there a way to prevent this? Can my threads have a higher priority when they need to run?

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Android :: Run Query On Background Thread On Cursoradapter Doesn't Get Called?

Jul 25, 2010

I have a listactivity as a startup screen in my application. Which is displaying database records using custom cursor adapter. On create I set the filterable flag - getListView().setTextFilterEnabled(true)

My cursoradapter overrides runQueryOnBackgroundThread which runs corresponding query. The problem is that after typing some text and hitting enter, runQueryOnBackgroundThread never gets called. However, when the item click in the same view launches another activity(detail view of the record) and I come back to the original list activity, hitting back button, then text filtering works just fine. I don't call setTextFilterEnabled anywhere except during the initialization process and I can't really find any other API affecting this behavior, so any guesses why text filtering doesn't work initially, but all of the sudden starts working when I come back to the list activity from child activity?

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Android :: Using Selector To Change ImageButton's Background While Keeping Content Image

Apr 18, 2010

I am currently trying to customize ImageButton to show different draweables as background of the Button while keeping the image set via the src attribute.

That's my custom_button.xml:

CODE:..............

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Android :: Background Thread - Application To Sync Contacts Largest Number

Oct 18, 2010

I am working on an application to sync contacts which are large in number. The syncing takes place in a background thread with user being able to browse through the rest of the application. I am displaying the sync status in the notification bar suing the progress bar. The problem I am facing is that there are instances when the activity is killed and hence the background thread used for syncing the contacts is purged.

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Android :: ASync Task Progress Dialog Not Showing Until Background Thread Finishes

Apr 24, 2010

I'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?

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Android :: How To Handle Screen Orientation Change / When Progress Dialog And Background Thread Active?

Jul 10, 2009

My program does some network activity in a background thread. Before starting, it pops up a progress dialog. The dialog is dismissed on the handler.This all works fine, except when screen orientation changes while the dialog is up (and the background thread is going). At this point the app either crashes, or deadlocks, or gets into a weird stage where the app does not work at all until all the threads have been killed.How can I handle the screen orientation change gracefully?

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Android : Java - Implement A Run Method Of Thread If Create A Thread Global

Sep 7, 2010

How can I implement a run() method of thread if I create a Thread Global?

I mean If I create a Thread Globally then can I implement its run() method {" public void run()"} anywhere in my Application?

In the run() method I have to write the code to perform some action.

IF I can do it then please can anyone show me briefly how to do it particularly.

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Android : Handle Messages Between The Main Thread(the Deafult UI Related Thread) And The User Created Gamethread

May 21, 2009

I am writing an application in which i need to handle messages between the main thread(the deafult UI related thread) and the user created Gamethread.

The requirement is like this.

An activity(say "Activity_X") is setting the view by "setContentView(some "View_Y")". In "Activity_X" i have implemeted "onCreateOptionsMenu()" and "onOptionsItemSelected()" fucntions for creating menus & a switch case for action to be taken on selecting those menus.Menu has items like "resume/pause/zoom/" .

All action to be take on selecting these menus are implemented in "View_Y" in a separate Gamethread by extending "Thread" class.

So whenever a menu is selected in "Activity_X" i need to send a message to "View_Y". And on receiving this ,a particular action/method should be called in View_Y(GameThread).

How can i achieve this using Handlers?Is there any other way of doing this? Please do share with me some code snippets for these.

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Android :: Update ListView In Main Thread From Another Thread

May 27, 2010

I have a separate thread running to get data from the internet. After that, I would like to update the ListView in the main thread by calling adapter.notifyDataSetChanged(). But it does not work. Any workaround for that?

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Android :: Use Thread With SurfaceView - Ie Draw In Separate Thread?

Jul 22, 2009

I want to do the drawing in another thread to speed up the game(it is way to slow right now). I was told to do this but don't quite understand why that would speed things up. Is it GameView that should implement Runnable? Should I make the thread sleep when not drawing? where should I start the thread? package com.android.WWS;

import android.app.Activity; import android.content.Context; import android.graphics.*; import android.os.Bundle; import android.view.SurfaceView; import android.view.KeyEvent; import android.view.View; import android.view.View.OnKeyListener; import java.lang.Runnable; import java.lang.Thread;...................

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Android :: Switching Content Providers For Same Content URI

Aug 12, 2009

This may seem like a stupid question but I need to be sure. I was wondering if it was possible to pro-grammatically change the Content Provider used when making a query given a Content URI. The reason being I need to know if it's possible to force the Calendar/Contacts applications to read from a different database via a different Content Provider temporarily while my application is running, so that I can reuse those applications to display my own data. Since the Content URI s are hard coded in each of these applications the only way it might be possible is if we could somehow temporarily change the Content Provider used for a given URI. I know this probably isn't possible, I just need to show it isn't. Could someone confirm this can't be done?

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Android :: Suspend / Resume Thread From Another Thread In Same App

Feb 20, 2009

I need to suspend/resume a thread from another thread in the same process. I tried to look into thread apis,but I couldn't figured out a way to achieve this.Can anyone pls point me some references to look or give a tip to do this.

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HTC Droid Eris :: Remove Certain Texts From Thread In Easily Instead Of Whole Thread?

Dec 28, 2009

Does anyone know how to delete certain texts from a thread in an easy manner instead of having to delete a whole thread??

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Android :: Modifying The UI Within Java - Not XML

Jul 11, 2009

So I have the basics down... I can create a UI with the XML, I can show it and change the screen to another UI (another XML file) but how do I add to the UI?

Hard to explain...

Say I have a header (just 2 textviews) that will remain at the top and below that is a search box and button (main.xml). The user searches and I have it display the search UI (search.xml). This UI will have the same header (2 textviews) and below it will have several textviews each one containing a search result... Kinda like if you search for an app in the market. There's no way of telling how many results would be returned so I figured I would have to create each textview on the fly within the .java file. I'm not sure how to do this. Most likely would require a loop of some sort, but whats the syntax to create a new textview and display it right below the one above it? I'm working with linear here so I would assume just creating a new textview it will by default go to the next one down which is what I want.

Also, say I have 30 results... How do I get those to scroll but leave the 2 textview header in place? Would I create a ScrollView and put the new TextViews in that?

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Android : Content Provider - No Link Between Content Provider And Its CONTENT_URI Declared In Another Class

Mar 1, 2010

I am having a hard time understanding content providers. In the notepad example and others, the content provider never even declares its CONTENT_URI anywhere inside itself, yet the docs say to publicly declare this. It's declared in a different class. So when an activity queries a content provider with a CONTENT_URI, how does Android know which one I want. I see no link between a content provider and its CONTENT_URI declared in another class.

I also don't how to think about intents and content providers. I know that you don't call an intent on a content provider. But an activity queries a content provider without an intent, and an activity has a mimetype attribute in the manifest that would seem to tie it to a content provider.

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Android :: Main Thread The Same As UI Thread?

Jul 16, 2010

The Android doc says "Like activities and the other components, services run in the main thread of the application process." Is the main thread here the same thing as UI thread?

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