Java 需要帮助计算android中用户和位置之间的距离吗

我想将用户在handleNewLocation方法中的位置存储在一个变量中，并计算到变量x的距离。我一直在搜索全局变量，但似乎都不起作用

/*
 * Define a request code to send to Google Play services
 * This code is returned in Activity.onActivityResult
 */
private final static int CONNECTION_FAILURE_RESOLUTION_REQUEST = 9000;

private GoogleMap mMap; // Might be null if Google Play services APK is not available

private GoogleApiClient mGoogleApiClient;
private LocationRequest mLocationRequest;

public double currentLatitude;
public double currentLongitude;
private LatLng userLocation = new LatLng(currentLatitude,currentLongitude);
public LatLng Besabella= new LatLng(10.351763, 123.953683);
private LatLng StPeter= new LatLng(10.351910, 123.952619);
private double x = CalculationByDistance(userLocation,Besabella);
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);
    setUpMapIfNeeded();

    mGoogleApiClient = new GoogleApiClient.Builder(this)
            .addConnectionCallbacks(this)
            .addOnConnectionFailedListener(this)
            .addApi(LocationServices.API)
            .build();

    // Create a LocationRequest object
    mLocationRequest = LocationRequest.create()
            .setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY)
            .setInterval(10 * 1000)        // 10 seconds, in milliseconds
            .setFastestInterval(1 * 1000); // 1 second, in milliseconds
}

@Override
protected void onResume() {
    super.onResume();
    setUpMapIfNeeded();
    mGoogleApiClient.connect();
}

@Override
protected void onPause() {
    super.onPause();

    if (mGoogleApiClient.isConnected()) {
        LocationServices.FusedLocationApi.removeLocationUpdates(mGoogleApiClient, this);
        mGoogleApiClient.disconnect();
    }
}
public double CalculationByDistance(LatLng StartP, LatLng EndP) {
    int Radius = 6371;// radius of earth in Kilometers
    double lat1 = StartP.latitude;
    double lat2 = EndP.latitude;
    double lon1 = StartP.longitude;
    double lon2 = EndP.longitude;
    double dLat = Math.toRadians(lat2 - lat1);
    double dLon = Math.toRadians(lon2 - lon1);
    double a = Math.sin(dLat / 2) * Math.sin(dLat / 2)
            + Math.cos(Math.toRadians(lat1))
            * Math.cos(Math.toRadians(lat2)) * Math.sin(dLon / 2)
            * Math.sin(dLon / 2);
    double c = 2 * Math.asin(Math.sqrt(a));
    double valueResult = Radius * c;
    double km = valueResult / 1;
    DecimalFormat newFormat = new DecimalFormat("####");
    int kmInDec = Integer.valueOf(newFormat.format(km));
    double meter = valueResult % 1000;
    int meterInDec = Integer.valueOf(newFormat.format(meter));
    Log.i("Radius Value", "" + valueResult + "   KM  " + kmInDec
            + " Meter   " + meterInDec);

    return Radius * c;
}
private void setUpMapIfNeeded() {
    // Do a null check to confirm that we have not already instantiated the map.
    if (mMap == null) {
        // Try to obtain the map from the SupportMapFragment.
        mMap = ((SupportMapFragment) getSupportFragmentManager().findFragmentById(R.id.map))
                .getMap();
        // Check if we were successful in obtaining the map.
        if (mMap != null) {
            setUpMap();
        }
    }
}


private void setUpMap() {


    mMap.addMarker(new MarkerOptions()
            .position(new LatLng(10.351763, 123.953683))
            .title("Besabella Parking Lot")
            .snippet("Distance : " + x + " KM ")
            .icon(BitmapDescriptorFactory.fromBitmap(resizeMapIcons("p_icon", 100, 100))));

    mMap.addMarker(new MarkerOptions()
            .position(new LatLng(10.351910, 123.952619))
            .title("St. Peter Agrivet Pay Parking")
            .icon(BitmapDescriptorFactory.fromBitmap(resizeMapIcons("p_icon",100,100))));

    mMap.addMarker(new MarkerOptions()
            .position(new LatLng(10.352203, 123.957021))
            .title("Norbads Parking Lot")
            .icon(BitmapDescriptorFactory.fromBitmap(resizeMapIcons("p_icon",100,100))));

    mMap.addMarker(new MarkerOptions()
            .position(new LatLng(10.329674, 123.943967))
            .title("Accu-Carwash and Pay Parking")
            .icon(BitmapDescriptorFactory.fromBitmap(resizeMapIcons("p_icon", 100, 100))));

    mMap.addMarker(new MarkerOptions()
            .position(new LatLng(10.340262, 123.941552))
            .title("Entica pay parking")
            .icon(BitmapDescriptorFactory.fromBitmap(resizeMapIcons("p_icon", 100, 100))));

    mMap.addMarker(new MarkerOptions()
            .position(new LatLng(10.345590, 123.959633))
            .title("Bongo's pay parking")
            .icon(BitmapDescriptorFactory.fromBitmap(resizeMapIcons("p_icon", 100, 100))));

    mMap.addMarker(new MarkerOptions()
            .position(new LatLng(10.341577, 123.913261))
            .title("EDSHAI HOMEOWNERS")
            .icon(BitmapDescriptorFactory.fromBitmap(resizeMapIcons("p_icon", 100, 100))));

}

private void handleNewLocation(Location location) {
    Log.d(TAG, location.toString());

    currentLatitude = location.getLatitude();
    currentLongitude = location.getLongitude();
    LatLng userLocation= new LatLng(currentLatitude, currentLongitude);


    //mMap.addMarker(new MarkerOptions().position(new LatLng(currentLatitude, currentLongitude)).title("Current Location"));
    MarkerOptions options = new MarkerOptions()
            .position(userLocation)
            .title("YOU ARE HERE")
            .icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_AZURE));
    mMap.addMarker(options);
    // Move the camera instantly to location with a zoom of 15.
    mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(userLocation, 15));

    // Zoom in, animating the camera.
    mMap.animateCamera(CameraUpdateFactory.zoomTo(14), 2000, null);

    addCircleToMap(currentLatitude, currentLongitude);

}

@Override
public void onConnected(Bundle bundle) {
    Location location = LocationServices.FusedLocationApi.getLastLocation(mGoogleApiClient);
    if (location == null) {
        LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
    }
    else {
        handleNewLocation(location);
    }
}

@Override
public void onConnectionSuspended(int i) {

}

@Override
public void onConnectionFailed(ConnectionResult connectionResult) {
    /*
     * Google Play services can resolve some errors it detects.
     * If the error has a resolution, try sending an Intent to
     * start a Google Play services activity that can resolve
     * error.
     */
    if (connectionResult.hasResolution()) {
        try {
            // Start an Activity that tries to resolve the error
            connectionResult.startResolutionForResult(this, CONNECTION_FAILURE_RESOLUTION_REQUEST);
            /*
             * Thrown if Google Play services canceled the original
             * PendingIntent
             */
        } catch (IntentSender.SendIntentException e) {
            // Log the error
            e.printStackTrace();
        }
    } else {
        /*
         * If no resolution is available, display a dialog to the
         * user with the error.
         */
        Log.i(TAG, "Location services connection failed with code " + connectionResult.getErrorCode());
    }
}

@Override
public void onLocationChanged(Location location) {
    handleNewLocation(location);
}

public void addCircleToMap(double lat, double longi) {

    // circle settings
    int radiusM = 1000; // your radius in meters
    double latitude2 = lat; // your center latitude
    double longitude2 =  longi; // your center longitude

            LatLng latLng = new LatLng(latitude2,longitude2);

    // draw circle
    int d = 500; // diameter
    Bitmap bm = Bitmap.createBitmap(d, d, Bitmap.Config.ARGB_8888);
    Canvas c = new Canvas(bm);
    Paint p = new Paint();
    p.setColor(getResources().getColor(R.color.wallet_holo_blue_light));
    c.drawCircle(d/2, d/2, d/2, p);

    // generate BitmapDescriptor from circle Bitmap
    BitmapDescriptor bmD = BitmapDescriptorFactory.fromBitmap(bm);

// mapView is the GoogleMap
    mMap.addGroundOverlay(new GroundOverlayOptions().
            image(bmD).
            position(latLng,radiusM*2,radiusM*2).
            transparency(0.4f));
    }

}

试试这个

Location locationA = new Location("point A");
    locationA.setLatitude(lat);
    locationA.setLongitude(lon);
    Location locationB = new Location("point B");
    locationB.setLatitude(Constant.latitude);
    locationB.setLongitude(Constant.longitude);
    dist =locationA.distanceTo(locationB) ;

有关使用google places中的位置的信息，请参阅：