Question

我成功创建了谷歌地图。我可以检查mylocation，我写了代码女巫可以在谷歌地图（触摸听众）中添加点，并在开始位置和点之间画线。现在我想检查距离。我不知道我怎么能这样我用谷歌搜索了一个例子，但这段代码不能正常工作？我总是有一个距离这是我的代码，如果有人知道解决方案，请帮助我感谢

public class GPS extends Activity implements
    OnMyLocationChangeListener, OnMapClickListener {
final int RQS_GooglePlayServices = 1;
private GoogleMap myMap;
Circle myCircle;
TextView tvLocInfo, GPSLocation;
LatLng latLng;
boolean markerClicked;
ArrayList<LatLng> markerPoints;
double Startlatitude, Startlongitude, Endlatitude, Endlongitude;

public Button gpssize;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    requestWindowFeature(Window.FEATURE_NO_TITLE);
    setContentView(R.layout.gps);
    markerPoints = new ArrayList<LatLng>();

    gpssize = (Button) findViewById(R.id.gpssize);

    tvLocInfo = (TextView) findViewById(R.id.GpsTxt);
    GPSLocation = (TextView) findViewById(R.id.GPSLocation);
    FragmentManager myFragmentManager = getFragmentManager();
    MapFragment myMapFragment = (MapFragment) myFragmentManager
            .findFragmentById(R.id.GpsMap);
    myMap = myMapFragment.getMap();
    myMap.getUiSettings().setZoomControlsEnabled(true);
    myMap.getUiSettings().setCompassEnabled(true);
    myMap.getUiSettings().setMyLocationButtonEnabled(true);

    myMap.setMyLocationEnabled(true);
    myMap.setOnMyLocationChangeListener(this);

    gpssize.setOnClickListener(new OnClickListener() {

        @Override
        public void onClick(View v) {
            double distance;

            Location locationA = new Location("");

            locationA.setLatitude(Startlatitude);

            locationA.setLongitude(Startlongitude);

            Location locationB = new Location("");

            locationB.setLatitude(Endlatitude);

            locationB.setLongitude(Endlongitude);

            distance = locationA.distanceTo(locationB) / 1000;

            Toast.makeText(getApplicationContext(), "" + distance,
                    Toast.LENGTH_LONG).show();

        }
    });

    myMap.setOnMapClickListener(this);

    myMap.setTrafficEnabled(true);

    markerClicked = false;

}

@Override
protected void onResume() {

    super.onResume();

    int resultCode = GooglePlayServicesUtil
            .isGooglePlayServicesAvailable(getApplicationContext());

    if (resultCode == ConnectionResult.SUCCESS) {
        Toast.makeText(getApplicationContext(),
                "isGooglePlayServicesAvailable SUCCESS", Toast.LENGTH_LONG)
                .show();
    } else {
        GooglePlayServicesUtil.getErrorDialog(resultCode, this,
                RQS_GooglePlayServices);
    }

}

@Override
public void onMyLocationChange(Location location) {

    Startlatitude = location.getLatitude();

    Startlongitude = location.getLongitude();

    latLng = new LatLng(Startlatitude, Startlongitude);

    myMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));

    GPSLocation.setText(Startlatitude + " " + Startlongitude);
    // myMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);

    LatLng locLatLng = new LatLng(location.getLatitude(),
            location.getLongitude());
    double accuracy = location.getAccuracy();

    if (myCircle == null) {
        CircleOptions circleOptions = new CircleOptions().center(locLatLng)

        .radius(accuracy)

        .fillColor(Color.RED).strokeColor(Color.BLACK).strokeWidth(5);

        myCircle = myMap.addCircle(circleOptions);
    } else {
        myCircle.setCenter(locLatLng);
        myCircle.setRadius(accuracy);
    }
    myMap.animateCamera(CameraUpdateFactory.zoomTo(15));

}

private String getDirectionsUrl(LatLng origin, LatLng dest) {

    String str_origin = "origin=" + Startlatitude + "," + Startlongitude;

    String str_dest = "destination=" + dest.latitude + "," + dest.longitude;

    String sensor = "sensor=false";

    String parameters = str_origin + "&" + str_dest + "&" + sensor;

    String output = "json";

    String url = "https://maps.googleapis.com/maps/api/directions/"
            + output + "?" + parameters;

    return url;
}

/** A method to download json data from url */
private String downloadUrl(String strUrl) throws IOException {
    String data = "";
    InputStream iStream = null;
    HttpURLConnection urlConnection = null;
    try {
        URL url = new URL(strUrl);

        urlConnection = (HttpURLConnection) url.openConnection();

        urlConnection.connect();

        iStream = urlConnection.getInputStream();

        BufferedReader br = new BufferedReader(new InputStreamReader(
                iStream));

        StringBuffer sb = new StringBuffer();

        String line = "";
        while ((line = br.readLine()) != null) {
            sb.append(line);
        }

        data = sb.toString();

        br.close();

    } catch (Exception e) {
        Log.d("Exception while downloading url", e.toString());
    } finally {
        iStream.close();
        urlConnection.disconnect();
    }
    return data;
}

private class DownloadTask extends AsyncTask<String, Void, String> {

    @Override
    protected String doInBackground(String... url) {

        String data = "";

        try {

            data = downloadUrl(url[0]);
        } catch (Exception e) {
            Log.d("Background Task", e.toString());
        }
        return data;
    }

    @Override
    protected void onPostExecute(String result) {
        super.onPostExecute(result);

        ParserTask parserTask = new ParserTask();

        parserTask.execute(result);

    }
}

private class ParserTask extends
        AsyncTask<String, Integer, List<List<HashMap<String, String>>>> {

    @Override
    protected List<List<HashMap<String, String>>> doInBackground(
            String... jsonData) {

        JSONObject jObject;
        List<List<HashMap<String, String>>> routes = null;

        try {
            jObject = new JSONObject(jsonData[0]);
            DirectionsJSONParser parser = new DirectionsJSONParser();

            routes = parser.parse(jObject);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return routes;
    }

    @Override
    protected void onPostExecute(List<List<HashMap<String, String>>> result) {
        ArrayList<LatLng> points = null;
        PolylineOptions lineOptions = null;
        MarkerOptions markerOptions = new MarkerOptions();

        for (int i = 0; i < result.size(); i++) {
            points = new ArrayList<LatLng>();
            lineOptions = new PolylineOptions();

            List<HashMap<String, String>> path = result.get(i);

            for (int j = 0; j < path.size(); j++) {
                HashMap<String, String> point = path.get(j);

                double lat = Double.parseDouble(point.get("lat"));
                double lng = Double.parseDouble(point.get("lng"));
                tvLocInfo.setText(lat + " " + lng);

                LatLng position = new LatLng(lat, lng);
                points.add(position);
            }

            lineOptions.addAll(points);
            lineOptions.width(7);
            lineOptions.geodesic(true);

            lineOptions.color(getResources().getColor(R.color.mapColor));

        }

        myMap.addPolyline(lineOptions);
    }
}

@Override
public void onMapClick(LatLng point) {
    if (markerPoints.size() > 0) {
        markerPoints.clear();
        myMap.clear();
    }

    markerPoints.add(point);

    MarkerOptions options = new MarkerOptions();

    options.position(point);

    if (markerPoints.size() == 1) {
        options.icon(BitmapDescriptorFactory
                .defaultMarker(BitmapDescriptorFactory.HUE_GREEN));
    }

    myMap.addMarker(options);

    if (markerPoints.size() >= 1) {

        LatLng dest = markerPoints.get(0);
        LatLng origin = new LatLng(Endlatitude, Endlongitude);

        String url = getDirectionsUrl(origin, dest);

        DownloadTask downloadTask = new DownloadTask();

        downloadTask.execute(url);
    }

}

}

Answer 1

尝试通过这种方式将Distance提升到LatLng点之间：

float[] distances = new float[1];
Location.distanceBetween(locationA.latitude, locationA.longitude,
                locationB.latitude, locationB.longitude,
                distances);

System.out.println("Distance: " + distances[0]);

Android谷歌地图查找之间的距离

1 个答案: