Question

So I have an application that draws line, polyline, circles, etc over an Open Streen Map. I keep a list of drawings, when the map is invalidated I iterate though the list redrawing each item within the onDraw method of an Overlay. This works fine until my drawing count gets around 300+. Then some serious UI delay kicks in.

我期待有效率地做到这一点?

I ve done bitmap cache drawing on a "board" drawing application. Although that will not work for this situation as the projection in the background can change, thus the drawing must move.

Answer 1

当时,我节省了Geo Points,然后在每批重水中将“MapView Point”改为“MapView Point”。 “中间点”可以储存起来,很容易预测到“MapView Point”。因此,重算部分只做了一次。

步骤

Motion Event(x,y) to GeoPoint using (fromPixels)
GeoPoint to Intermediate value using (toMapPixelsProjected)
Cache the intermediate values for drawing display
OnDraw -> intermediate values to screen coordinates using (toMapPixelsTranslated)

友情链接