计算Android中两个标记之间的距离

Question

For an app that I'm currently working on I want to set up a button that finds the distance between two markers on a google maps activity and when you click the button it shows the distance between your current location and the other marker I don't have any code in my java class for the button yet but at the moment I'm just wondering how I actually find the distance between my current location and my set up marker. Here's my code for finding the users current location and it has a marker set up in a random location.

package dashpage.example.com.myapplication;

import android.content.IntentSender;
import android.location.Location;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;

import com.google.android.gms.common.ConnectionResult;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.location.LocationListener;
import com.google.android.gms.location.LocationRequest;
import com.google.android.gms.location.LocationServices;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;

public class MapsActivity extends FragmentActivity implements
        GoogleApiClient.ConnectionCallbacks,
        GoogleApiClient.OnConnectionFailedListener,
        LocationListener {

    public static final String TAG = MapsActivity.class.getSimpleName();

    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;

    @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 the 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();
        }
    }

    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(53.3835, 6.5996)).title("Marker"));
    }

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

        double currentLatitude = location.getLatitude();
        double currentLongitude = location.getLongitude();

        LatLng latLng = new LatLng(currentLatitude, currentLongitude);

        //mMap.addMarker(new MarkerOptions().position(new LatLng(currentLatitude, currentLongitude)).title("Current Location"));
        MarkerOptions options = new MarkerOptions()
                .position(latLng)
                .title("I am here!");
        mMap.addMarker(options);
        mMap.moveCamera(CameraUpdateFactory.newLatLng(latLng));
    }

    @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) {
        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);
    }
}

I also know that for finding the distance between two markers in Android Studio you'd use something like

Location loc1 = new Location("");
loc1.setLatitude(lat1);
loc1.setLongitude(lon1);

Location loc2 = new Location("");
loc2.setLatitude(lat2);
loc2.setLongitude(lon2);

float distanceInMeters = loc1.distanceTo(loc2);

So I'm just wondering if anybody would be able to help me implement the code for finding the distance because I'm not sure where it should go in my class or if I'll have to redo some parts of the class to make the distance work

Answer 1

When trying to find distance between markers, I would recommend to convert them back to Location objects to be able to use the in-built Android method of calculating distance.

Given some Marker marker that you have set up and have access through onMarkerClick() or already saved and current position Location currentLocation , inside your onClick(View v) method for the Button :

LatLng markerLatLng = marker.getPosition();
Location markerLocation = new Location("");
markerLocation.setLatitude(markerLatLng.latitude);
markerLocation.setLongitude(markerLatLng.longitude);

currentLocation.distanceTo(markerLocation);

Answer 2

Hi I made an example and its like your qquestion.But you must customise for your build.You can use Collections class.Its easy and perfectly work.

   Comparator<Sinemalar> comparator=new Comparator<Sinemalar>() {
            @Override
            public int compare(Sinemalar left, Sinemalar right) {
                return (int)(left.getDistance()-right.getDistance());

            }
        };
        Collections.sort(sinemalarList, comparator);

I hope work for you

 public float distanceCounter(String value, Context context) {
    Location cinemaLocation = new Location("CinemaLocation");
    String s = new String(value);
    String[] result = s.split(",");
    List<String> elephantList = Arrays.asList(s.split(","));
    String longitude = elephantList.get(1);
    String latitude = elephantList.get(0);
    cinemaLocation.setLatitude(Double.parseDouble(latitude));
    cinemaLocation.setLongitude(Double.parseDouble(longitude));

 float distance = getCurrrentLocation(context).distanceTo(cinemaLocation)/1000 ;

    return distance;
}

String value=34.54665 , 23.54546

Full code here you can use with here.Sory i forgot.