連續跟蹤用戶的位置並繪制路徑

Question

好吧，我開發了一個android程序來獲取您的位置。 現在我想要的是到達正確的位置並跟蹤您的運動，並在路徑圖上畫一條線。 閱讀了大量指南，但根本無法使它起作用

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

您編寫的所有代碼均已編寫，但是在Application啟動時您無法在onLocationChanged上工作。

1. 如果存在緩存，則getLastKnownLocation返回location，否則返回null並在此處添加檢查。

     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位置fusedlocation api ，可通過位置進行更好的管理。

3. 試試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); } } 

請參閱此處： http : //coderzpassion.com/android-google-maps-v2-tutorial-with-markers/

4. onLocationChanged(Location location):如果現有位置為空或當前位置精度大於現有精度，則存儲當前位置。

因此，您需要修改onLocationChanged（Location location）並將要更改的應用程序狀態值寫入如下代碼：

@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


}

希望能幫助到你。