Hi, Peter,
Actually, if you look my code, I have a global array of overlay item.
And I override following code:
public int size()
{
return mFriendList.size();
}
public LptOverlayItem createItem(int i)
{
return mFriendList.get(i);
}
--elephantbug
On Sep 24, 10:56 pm, Peter Stevenson <[EMAIL PROTECTED]> wrote:
> Hi
>
> this can be trigger by not create OverlayItem
>
> //customizedItemizedOverlay
> protected class FriendOverLay extendsItemizedOverlay<OverlayItem>
>
> private List<OverlayItem> mItemList = new ArrayList<OverlayItem>();
>
> {
> public FriendOverLay(Drawable marker) {
> super(marker);
>
> *mItemList.add(new OverlayItem(whatAroundMe.currentPoint , "Title",
> "Snippet"));*
>
> populateFriends();
>
> }
>
> public synchronized void populateFriends()
> {
> mFriendList = DataManager.getInstance().getFriendLocations();
> super.populate();
>
> }
>
> @Override
> public void draw(Canvas canvas, MapView view, boolean shadow ) {
>
> super.draw(canvas, view, shadow);
> boundCenterBottom(marker);
>
> //draw other stuffs...
>
> }
> }
> }
>
> [EMAIL PROTECTED]
> protected OverlayItem createItem(int i) {
>
> return mItemList.get(i);
> }
>
> @Override
> public int size() {
>
> return mItemList.size();
> }*
>
> hope it helps
> Peter
>
> elephantbug wrote:
> > Hi, Mark,
>
> > Here is the code snip:
> > ----------------------------------------------
> > Main Map Screen
> > -----------------------------------------------
> > public class MyMapActivity extends MapActivity implements Observer{
>
> > //global array of overlay items
> > List<OverlayItem> mFriendList = Collections.synchronizedList(new
> > ArrayList<OverlayItem>());
>
> > public void onCreate(){
> > //init...(omit)
> > ...
> > //add itemized overlay
> > myOverLay = new FriendOverLay(marker);
> > mMapView.getOverlays().add(myOverLay);
>
> > //...}
>
> > //observer
> > public void update(Observable o, Object args) {
> > if(args instanceof Byte)
> > {
> > Byte event = (Byte)args;
> > if(event == EVENT_UPDATES)
> > {
> > // try to refresh the screen
> > runOnUiThread( new Runnable()
> > {
> > public void run()
> > {
> > if(myOverLay != null)
> > {
> >
> > myOverLay.populateFriends();
> > }
> > if(mMapView != null)
> >
> > mMapView.postInvalidateDelayed(5000);
> > }
>
> > });
>
> > }
> > }
> > }
>
> > //customizedItemizedOverlay
> > protected class FriendOverLay extendsItemizedOverlay<OverlayItem>
> > {
> > public FriendOverLay(Drawable marker) {
> > super(marker);
>
> > populateFriends();
> > }
>
> > public synchronized void populateFriends()
> > {
> > mFriendList =
> > DataManager.getInstance().getFriendLocations();
> > super.populate();
> > }
>
> > [EMAIL PROTECTED]
> > public void draw(Canvas canvas, MapView view, boolean shadow ) {
>
> > super.draw(canvas, view, shadow);
> > boundCenterBottom(marker);
>
> > //draw other stuffs...
> > }
> > }
> > }
>
> > -----------------------------
> > The data manager
> > -----------------------------
> > public class DataManager extends Observable{
>
> > private List<OverlayItem> friendStatus =
> > Collections.synchronizedList(new ArrayList<OverlayItem>());
>
> > public List<OverlayItem> getFriendLocations()
> > {
> > synchronized (friendAccessMutex) {
> > return friendStatus;
> > }
> > }
>
> > //will spawn a new thread to update the friendStaus array
> > periodically.and call setChange and notify the Map Screen (trigger
> > update())...
>
> > }
>
> > -----------------------------------------------------------------------
>
> > Most of time, it works fine. But sometimes ( I have not found the
> > pattern yet), it will trigger ArrayOutOfIndexException
> > on theItemizedOverlay.draw() method.
>
> > So basically, my question is how to achieve one screen display the
> > dynamic data onItemizedOverlay?
>
> > Any input is appreciated.
>
> > Thanks.
>
> > --elephantbug
>
> > On Sep 24, 6:34 pm, Mark Murphy <[EMAIL PROTECTED]> wrote:
>
> >> elephantbug wrote:
>
> >>> I extend the MapActivity and have anItemizedOverlaywhich will
> >>> display array of items(For example, people) on top of MapView. These
> >>> items' location are moving and some new items might be added in or
> >>> some might be removed. There is another thread managing these items.
>
> >>> MapActivity is the observer of these items and update the UI whenever
> >>> items changes. It works fine most of time. However, periodically, it
> >>> will cause trouble and makesItemizedOverlaythrow ArrayOutofIndex
> >>> exceptionrom getIndexToDraw() method.
>
> >>> Anyone can help me why it might happen and what is the best practice
> >>> to support dynamic data bind forItemizedOverlay?
>
> >> Without seeing your implementation of yourItemizedOverlaysubclass, it
> >> is difficult to make many suggestions.
>
> >> Bear in mind that if you change the data in a background thread, the
> >> foreground (UI) thread might still be working off of old information.
> >> For example, suppose you have six items, and the foreground thread is
> >> busy drawing those six items on the map. While that is happening, your
> >> background thread removes one item. The foreground thread has no way to
> >> know that occurred, so it will try requesting the sixth item...and will
> >> fail.
>
> >> Since I don't know how you are telling the MapView that there is changed
> >> data in theItemizedOverlay, I cannot make any particular suggestions of
> >> how to get around this problem. What *may* work is to change the
> >> contents of yourItemizedOverlayonly on the foreground (UI) thread --
> >> just have the background thread use a Handler or use runOnUiThread() or
> >> something to arrange for the work to get done on the foreground thread.
>
> >> --
> >> Mark Murphy (a Commons Guy)http://commonsware.com
> >> _The Busy Coder's Guide to Android Development_ Version 1.2 Published!
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