java - 持续跟踪用户的位置并绘制他所到之处的路径

Question

我开发了一个 Android 程序来获取你的位置。现在我想要的是准确地到达您所在的位置并跟踪您的 Action 并在您的路径 map 上画一条线。阅读了很多指南，但根本无法使其工作

public class MapsActivity extends FragmentActivity implements OnMapReadyCallback, LocationListener {

private GoogleMap mMap;
LocationManager locationManager;
String provider;


@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_maps);
    // Obtain the SupportMapFragment and get notified when the map is ready to be used.
    SupportMapFragment mapFragment = (SupportMapFragment)getSupportFragmentManager().findFragmentById(R.id.map);
    mapFragment.getMapAsync(this);
    locationManager = (LocationManager)    getSystemService(Context.LOCATION_SERVICE);
    provider = locationManager.getBestProvider(new Criteria(), false);

}

@Override
public void onMapReady(GoogleMap googleMap) {
    mMap = googleMap;
    Location location= locationManager.getLastKnownLocation(provider);
    double lat =location.getLatitude();
    double lng =location.getLongitude();
    mMap.addMarker(new MarkerOptions().position(new LatLng(lat, lng)).title("Marker"));

    // Add a marker and move the camera

}

@Override
public void onLocationChanged(Location location) {
    Double lat = location.getLatitude();
    Double lng = location.getLongitude();
    mMap.addMarker(new MarkerOptions().position(new LatLng(lat, lng)).title("Marker"));
    mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(lat, lng), 10));
    Log.i("Latitude", lat.toString());

}

Answer 1

您编写的所有代码都是写入的，但是您没有在应用程序启动时使用onLocationChanged。

1. getLastKnownLocation 如果存在缓存，则返回位置，否则返回 null，并在此处添加检查。

    if(location!=null) 
    {
   double lat =location.getLatitude(); 
   double lng =location.getLongitude();
   mMap.addMarker(new MarkerOptions().position(new 
   LatLng(lat,lng)).title("Marker")); }
   

2. fusedlocation api 为了更好地管理位置，请参阅此处。

3. 试试这个addMarker:

   public void drawMarker(double lat,double lon) {
    if (mMap != null) { 
      MarkerOptions marker = new MarkerOptions().position(new LatLng(lat, lon)).title(" Maps Tutorial").snippet("Android Ruler");      
      marker.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_GREEN)); 
      // Moving Camera to a Location with animation 
      CameraPosition cameraPosition = new CameraPosition.Builder().target(new LatLng(latitude, longitude)).zoom(12).build();
      mMap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition)); mMap.addMarker(marker); 
     } 
     }
   

请引用这里: http://coderzpassion.com/android-google-maps-v2-tutorial-with-markers/

onLocationChanged(位置位置):如果现有位置为空或当前位置精度高于现有精度，则存储当前位置。

所以，需要修改onLocationChanged(Location location)并将要更改的应用程序状态值写入如下代码:

@Override
public void onLocationChanged(Location location) {

    double latitude = location.getLatitude();
    double longitude = location.getLongitude();

    myLatLng = new LatLng(latitude, longitude);

    zoomToPoints();

    if(!isDirectionDrawn) {

        new LongOperation().execute("");
    }https://developers.google.com/android/reference/com/google/android/gms/location/FusedLocationProviderApi
}

private void moveToCurrentLocation(LatLng currentLocation)
    {
    mMap.moveCamera(CameraUpdateFactory.newLatLngZoom(currentLocation, 15));
    // Zoom in, animating the camera.
    mMap.animateCamera(CameraUpdateFactory.zoomIn());
    // Zoom out to zoom level 10, animating with a duration of 2 seconds.
    mMap.an


}

希望有帮助。