Android: Setting Zoom Level in Google Maps to include all Marker points

问题

I am trying to set zoom level for Maps in android such that it includes all the points in my list. I am using following code.

int minLatitude = Integer.MAX_VALUE;
int maxLatitude = Integer.MIN_VALUE;
int minLongitude = Integer.MAX_VALUE;
int maxLongitude = Integer.MIN_VALUE;

// Find the boundaries of the item set
// item contains a list of GeoPoints
for (GeoPoint item : items) { 
    int lat = item.getLatitudeE6();
    int lon = item.getLongitudeE6();

    maxLatitude = Math.max(lat, maxLatitude);
    minLatitude = Math.min(lat, minLatitude);
    maxLongitude = Math.max(lon, maxLongitude);
    minLongitude = Math.min(lon, minLongitude);
}
objMapController.zoomToSpan(
    Math.abs(maxLatitude - minLatitude), 
    Math.abs(maxLongitude - minLongitude));

this works sometimes. However sometimes some points are not shown and I need to then Zoom Out to view those points. Is there any way to solve this problem?

回答1:

Yet another approach with Android Map API v2:

private void fixZoom() {
    List<LatLng> points = route.getPoints(); // route is instance of PolylineOptions 

    LatLngBounds.Builder bc = new LatLngBounds.Builder();

    for (LatLng item : points) {
        bc.include(item);
    }

    map.moveCamera(CameraUpdateFactory.newLatLngBounds(bc.build(), 50));
}

回答2:

I found out the answer myself, the Zoom level was correct. I need to add following code to display all points on screen.

objMapController.animateTo(new GeoPoint( 
    (maxLatitude + minLatitude)/2, 
    (maxLongitude + minLongitude)/2 ));

The center point was not propery aligned creating problem for me. This works.

回答3:

Part of the problem could be that MIN_VALUE is still a positive number, but latitudes and longitudes can be negative numbers. Try using NEGATIVE_INFINITY instead of MIN_VALUE.

来源：https://stackoverflow.com/questions/5114710/android-setting-zoom-level-in-google-maps-to-include-all-marker-points

标签

android

google-maps

android-maps