Android MapView设置自动缩放,直到所有ItemizedOverlay都可见

Question

硬编码onCreate()中的setZoom()感觉非常陈旧,我想通过最初使MapView设置缩放直到所有GeoPoints/OverlayItems在地图上可见来增强用户体验.

怎么能自动神奇地完成？

Answer 1

有点像这样

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提出了一个很好的建议:放一个填充物使得一些点不会落在边缘上(谢谢Ryan!)

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