无法获得android studio中的当前位置

Question

我无法获取当前位置。这是我的代码：

标记显示在其他位置，但不显示在我当前位置。 我的xml看起来像这样：

<?xml version="1.0" encoding="utf-8"?>
<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:id="@+id/container"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context="com.example.app.MainActivity"
    tools:ignore="MergeRootFrame" >
    <LinearLayout
        android:orientation="vertical"
        android:layout_width="fill_parent"
        android:layout_height="fill_parent">
        <fragment
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:name="com.google.android.gms.maps.MapFragment"
            android:id="@+id/map" />
    </LinearLayout>
</FrameLayout>

这是我的班级：

public class MapsActivity extends AppCompatActivity implements LocationListener {

    private GoogleMap map;
    String strAdd;
    Location location;
    double latitude, longitude;


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_maps);


        map = ((MapFragment) getFragmentManager().findFragmentById(R.id.map)).getMap();

        map.setMapType(GoogleMap.MAP_TYPE_NORMAL);
        map.setMyLocationEnabled(true);
        map.getUiSettings().setZoomControlsEnabled(true);
        map.getUiSettings().setCompassEnabled(true);
        map.getUiSettings().setMyLocationButtonEnabled(true);
        map.getUiSettings().setZoomGesturesEnabled(true);
        map.getUiSettings().setRotateGesturesEnabled(true);

        LocationManager lm = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
        List<String> providers = lm.getProviders(true);
        Location l = null;

        for (int i = 0; i < providers.size(); i++) {
            if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                // TODO: Consider calling
                //    ActivityCompat#requestPermissions
                // here to request the missing permissions, and then overriding
                //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
                //                                          int[] grantResults)
                // to handle the case where the user grants the permission. See the documentation
                // for ActivityCompat#requestPermissions for more details.
                l = lm.getLastKnownLocation(providers.get(i));
                return;
            }

            if (l != null) {
                latitude = l.getLatitude();
                longitude = l.getLongitude();
                strAdd = getCompleteAddressString(latitude, longitude);
                break;
            }
        }

        if (map != null) {

            MarkerOptions marker = new MarkerOptions().position(
                    new LatLng(latitude, longitude)).title("Hello Maps").snippet("Discription");

            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();

            map.animateCamera(CameraUpdateFactory
                    .newCameraPosition(cameraPosition));

            map.addMarker(marker);

        }
    }



    private String getCompleteAddressString(double LATITUDE, double LONGITUDE) {
        String strAdd = "";
        Geocoder geocoder = new Geocoder(this, Locale.getDefault());
        try {
            List<android.location.Address> addresses = geocoder
                    .getFromLocation(LATITUDE, LONGITUDE, 1);
            if (addresses != null) {
                android.location.Address returnedAddress = addresses.get(0);
                StringBuilder strReturnedAddress = new StringBuilder("");

                for (int i = 0; i < returnedAddress.getMaxAddressLineIndex(); i++) {
                    strReturnedAddress
                            .append(returnedAddress.getAddressLine(i)).append(
                            "\n");
                }
                strAdd = strReturnedAddress.toString();
                Log.w("My Current loction address",
                        "" + strReturnedAddress.toString());
            } else {
                Log.w("My Current loction address", "No Address returned!");
            }
        } catch (Exception e) {
            e.printStackTrace();
            Log.w("My Current loction address", "Canont get Address!");
        }
        return strAdd;
    }

    @Override
    public void onLocationChanged(Location location) {
        if (map != null)
        {
            drawMarker(location);
        }
    }

    @Override
    public void onStatusChanged(String provider, int status, Bundle extras) {

    }

    @Override
    public void onProviderEnabled(String provider) {

    }

    @Override
    public void onProviderDisabled(String provider) {

    }
    private void drawMarker(Location location){
        map.clear();

//  convert the location object to a LatLng object that can be used by the map API
        LatLng currentPosition = new LatLng(location.getLatitude(), location.getLongitude());

// zoom to the current location
        map.animateCamera(CameraUpdateFactory.newLatLngZoom(currentPosition,16));


// add a marker to the map indicating our current position
        map.addMarker(new MarkerOptions()
                .position(currentPosition).title("Marker")
                        //   .icon(BitmapDescriptorFactory.fromResource(R.drawable.blue_point))
                .snippet("Lat:" + location.getLatitude() + "Lng:" + location.getLongitude()));
    }
}

我不知道我缺少的地方，请帮助。我们将非常感谢你的支持。因为我花了几天时间来克服这个问题，但没有用。

Answer 1

 @Override
    public void onLocationChanged(Location location) {
        double lat = location.getLatitude();
        double lng = location.getLongitude();

        LatLng coordinate = new LatLng(lat, lng);

        CameraUpdate cameraUpdate = CameraUpdateFactory.newLatLngZoom(coordinate, 10);

        map.animateCamera(cameraUpdate);
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
                != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission
                (this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
            locationManager.removeUpdates(this);
            return;
        }

    }

此代码适用于我。它还关注当前位置。