On 6/29/2010 3:12 PM, Steve Howard wrote:
I think some of the confusion might be coming from the fact that
you're expecting too much high-level logic from ItemizedOverlay.
ItemizedOverlay is a pretty basic class. You override size() and
createItem() to do whatever you want, and then you call populate()
anytime you want to update the items in the overlay. populate() will
call size() to figure out how many items are present, then call
createItem() once for each index 0 - [size() - 1].
How size() and createItem() work, and when populate() gets called, are
up to you. From your description, one possibility might be something
like this:
* Detect map movements by adding an empty Overlay and overriding the
draw() method. Use a delay timer to trigger an update after the map
stops moving for some threshold of time.
* Upon update, get the lat/long span of the MapView, as described, and
use it to query your database/server/whatever.
* When the results arrive, use them to fill in a member List on your
ItemizedOverlay subclass. Then call populate(). Your size() method
returns the length of the List; your createItem generates OverlayItems
from the data in that List.
It's a bit convoluted, no doubt -- some sample code would probably be
well-received here. Nonetheless, such an implementation should be
possible today.
<http://groups.google.com/group/android-developers?hl=en>
Thanks Steve! Ultimately, I ended up doing something very similar to
this, primarily based around onTouchEvent() in my ItemizedOverlay class.
Raymond
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