Distance between two location in Android map

Question

How to calculate distance between 2 location in android map & output must display in textview or any ?

Answer 1

/**
 * Calculate the distance between 2 points based on their GeoPoint coordinates. 

 * Return the value in Km or miles based on the unit input
 * @param gp1 (GeoPoint): First point.
 * @param gp2 (GeoPoint): Second point.
 * @param unit (char): Unit of measurement: 'm' for miles and 'k' for Km.
 * @return (double): The distance in miles or Km.
 */
public static double getDistance(GeoPoint gp1, GeoPoint gp2, char unit)
{
    //Convert from degrees to radians
    final double d2r = Math.PI / 180.0;

    //Change lat and lon from GeoPoint E6 format
    final double lat1 = gp1.getLatitudeE6() / 1E6;
    final double lat2 = gp2.getLatitudeE6() / 1E6;
    final double lon1 = gp1.getLongitudeE6() / 1E6;
    final double lon2 = gp2.getLongitudeE6() / 1E6;

    //The difference between latitudes and longitudes
    double dLat = Math.abs(lat1 - lat2) * d2r;
    double dLon = Math.abs(lon1 - lon2) * d2r;

    double a = Math.pow(Math.sin(dLat / 2.0), 2) 
            + Math.cos(lat1 * d2r) * Math.cos(lat2 * d2r)
            * Math.pow(Math.sin(dLon / 2.0), 2);

    double c = 2 * Math.atan2(Math.sqrt(a), Math.sqrt(1 - a));

    //Return the distance
    return (unit == 'm' ? 3956 : 6367) * c;
} //End getDistance()


TextView textView.setText("" + getDistance(gp1, gp2, 'k'));