Android MapView -setting zoom automatically until all ItemizedOverlay's are visible

问题

hard-coding the setZoom() within onCreate() feels very antiquated and I\'d like to enhance the user experience by initially having the MapView set the zoom until all GeoPoints / OverlayItems are visible on the map.

How can this be done auto-magically?

回答1:

Kinda like this

int minLat = Integer.MAX_VALUE;
int maxLat = Integer.MIN_VALUE;
int minLon = Integer.MAX_VALUE;
int maxLon = Integer.MIN_VALUE;

for (GeoPoint item : items) 
{ 

      int lat = item.getLatitudeE6();
      int lon = item.getLongitudeE6();

      maxLat = Math.max(lat, maxLat);
      minLat = Math.min(lat, minLat);
      maxLon = Math.max(lon, maxLon);
      minLon = Math.min(lon, minLon);
 }

mapController.zoomToSpan(Math.abs(maxLat - minLat), Math.abs(maxLon - minLon));
mapController.animateTo(new GeoPoint( (maxLat + minLat)/2, 
(maxLon + minLon)/2 )); 

---

edit: Ryan gave a nice suggestion : to put a padding so that some of the point don't lie on the edges (thanks Ryan!)

double fitFactor = 1.5;
mapController.zoomToSpan((int) (Math.abs(maxLat - minLat) * fitFactor), (int)(Math.abs(maxLon - minLon) * fitFactor));

回答2:

There's no magical way to achieve this. I suggest to iterate through all your overlayitems to obtain the center and span of all these items. Then set the center and span accordingly for the map

来源：https://stackoverflow.com/questions/5241487/android-mapview-setting-zoom-automatically-until-all-itemizedoverlays-are-visi