Android: How do I set the zoom level of map view to 1 km radius around my current location?

Solution 1:

although this answer is logical and i find it working but the results are not accurate i dont know why but i tired this approach and this technique is far more accurate.

1) Make a circle on object with desired radius

Circle circle = mGoogleMap.addCircle(new CircleOptions().center(new LatLng(latitude, longitude)).radius(getRadiusInMeters()).strokeColor(Color.RED));           
        circle.setVisible(true);
        getZoomLevel(circle);

2) Pass that object to this function and set the zoom level Here's a link

public int getZoomLevel(Circle circle) {
if (circle != null){
    double radius = circle.getRadius();
    double scale = radius / 500;
    zoomLevel =(int) (16 - Math.log(scale) / Math.log(2));
}
return zoomLevel;
}

Solution 2:

The following code is what ended up using. Given the screen width and the fact that at zoom level 1 the equator of Earth is 256 pixels long and every subsequent zoom level doubles the number of pixels needed to represent earths equator, the following function returns the zoom level where the screen will show an area of 2Km width.

private int calculateZoomLevel(int screenWidth) {
    double equatorLength = 40075004; // in meters
    double widthInPixels = screenWidth;
    double metersPerPixel = equatorLength / 256;
    int zoomLevel = 1;
    while ((metersPerPixel * widthInPixels) > 2000) {
        metersPerPixel /= 2;
        ++zoomLevel;
    }
    Log.i("ADNAN", "zoom level = "+zoomLevel);
    return zoomLevel;
}