变量已经在范围内定义？

Question

您好，我在实施我使用半正弦公式计算 Java 中的距离的方法时遇到了问题。

我尝试实现它的部分是：

            if(gps.canGetLocation()){

                double latitude1 = gps.getLatitude();
                double longitude1 = gps.getLongitude();

                double atrium_longitude = -122.6078622;
                double atrium_latitude = 49.170241;

                //double latitude = 49.1702665;
                //double longitude = -122.6078454;
                String atriumString = "Atrium";
                double distanceMeters = (latitude1, longitude1, atrium_latitude, atrium_longitude, atriumString);

                TextView distanceToText;
                distanceToText = (TextView) findViewById(R.id.distanceTo);

                distanceToText.setText("" + distanceMeters);
                // \n is for new line
                Toast.makeText(getApplicationContext(), "Your Location is - \nLat: " + latitude1 + "\nLong: " + longitude1 + "\n", Toast.LENGTH_LONG).show();
            }else{
                // can't get location
                // GPS or Network is not enabled
                // Ask user to enable GPS/network in settings
                gps.showSettingsAlert();
            }

Haversine 方法是：

public static double calculateDistance(double latitude1, double longitude1, double latitude2, double longitude2, String buildingName) {
    double toRad = (Math.PI/180);
//double latitude = gps.getLatitude();
//double longitude = gps.getLongitude();

//double latitude = 49.1702665;
//double longitude = -122.6078454;

double radius = 6371000;
double lat1 = latitude1 * toRad;
double lon1 = longitude1 * toRad;

double lat2 = latitude2 * toRad;
double lon2 = longitude2 * toRad;

double deltaLat = (latitude2 - latitude1) * toRad;
double deltaLon = (longitude2 - longitude1) * toRad;

double aHaversine = Math.sin(deltaLat/2) * Math.sin(deltaLat/2) +
        Math.cos(lat1) * Math.cos(lat2) *
                Math.sin(deltaLon/2) * Math.sin(deltaLon/2);

double cHaversine = 2 * Math.atan2(Math.sqrt(aHaversine), Math.sqrt(1-aHaversine));

double distanceHaversine = radius * cHaversine;

return distanceHaversine;

}

我相信我的方法是正确的，但我可能是错的，因为我只是大学一年级的业余编程。另外，如果有更有效的方法来实现这个公式，请务必告诉我。

Answer 1

看起来您实际上并没有调用您编写的 calculateDistance() 方法。

我认为这一行：

double distanceMeters = (latitude1, longitude1, atrium_latitude, atrium_longitude, atriumString);

应该是：

double distanceMeters = calculateDistance(latitude1, longitude1, atrium_latitude, atrium_longitude, atriumString);

这可能只是复制和粘贴错误。如果是这样，请使用您遇到的任何编译/运行时间错误更新您的问题。

变量已经在范围内定义？

Variable already define in scope?

android

gps

haversine