polyline not visible in google maps

问题:

I am trying to add polyline connecting a group of points in google maps.When i build the app I am not getting any error but polyline does not appear.If i call isvisible() method it returns true.Please Help

@Override
public void onMapReady(GoogleMap googleMap) {
   // new LongOperation().execute("");

   /* googleMap.setMapStyle(
            MapStyleOptions.loadRawResourceStyle(
                    this, R.raw.mapjson));*/

    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.
        return;
    }
    googleMap.setMyLocationEnabled(true);
    googleMapnew = googleMap;
    Polyline polyline1 = googleMap.addPolyline(new PolylineOptions()
            .clickable(true)
            .add(
                    new LatLng(13.034063, 77.567006 ),
                    new LatLng(13.034087, 77.568629),
                    new LatLng(13.034202, 77.569431),
                    new LatLng(13.034371, 77.570103),
                    new LatLng(13.034535, 77.570121),
                    new LatLng(13.036526, 77.570489),
                    new LatLng(13.037719, 77.570545),
                    new LatLng(13.038252, 77.570039),
                    new LatLng(13.039849, 77.570028),
                    new LatLng(13.040153, 77.569229),
                    new LatLng(13.040640, 77.568512),
                    new LatLng(13.041071, 77.567996),
                    new LatLng(13.041780, 77.567894))
    .color(Color.GREEN)
    .width(66));
    Log.e("polylog", String.valueOf(polyline1.isVisible()));
    Log.e("polylog", String.valueOf(polyline1));

}

回答1:

The issue is in

googleMap.setMyLocationEnabled(true);

line, because you probably didn't grant ACCESS_FINE_LOCATION and ACCESS_COARSE_LOCATION to your app. You should grant it manually to your application via Applications menu of your Android device or implement checking and grant permissions like in Official Documentation and, for example, this answer of Daniel Nugent, something like that:

public class MainActivity extends AppCompatActivity implements OnMapReadyCallback {

    private static final int LOCATION_PERMISSION_REQUEST_CODE = 101;
    private GoogleMap mGoogleMap;
    private MapFragment mMapFragment;

    private void makeLocationPermissionRequest() {
        ActivityCompat.requestPermissions(this,
                new String[]{android.Manifest.permission.ACCESS_FINE_LOCATION}, LOCATION_PERMISSION_REQUEST_CODE);
    }

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

        mMapFragment = (MapFragment) getFragmentManager()
                .findFragmentById(R.id.map_fragment);
        mMapFragment.getMapAsync(this);
    }

    private void showPolyline() {

        mGoogleMap.setMyLocationEnabled(true);

        Polyline polyline1 = mGoogleMap.addPolyline(new PolylineOptions()
                .clickable(true)
                .add(
                        new LatLng(13.034063, 77.567006 ),
                        new LatLng(13.034087, 77.568629),
                        new LatLng(13.034202, 77.569431),
                        new LatLng(13.034371, 77.570103),
                        new LatLng(13.034535, 77.570121),
                        new LatLng(13.036526, 77.570489),
                        new LatLng(13.037719, 77.570545),
                        new LatLng(13.038252, 77.570039),
                        new LatLng(13.039849, 77.570028),
                        new LatLng(13.040153, 77.569229),
                        new LatLng(13.040640, 77.568512),
                        new LatLng(13.041071, 77.567996),
                        new LatLng(13.041780, 77.567894))
                .color(Color.GREEN)
                .width(66));

        mGoogleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(new LatLng(13.034063, 77.567006), 12));
    }

    @Override
    public void onMapReady(GoogleMap googleMap) {
        mGoogleMap = googleMap;

        if (android.os.Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
            int locationPermission = ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION);
            if (locationPermission != PackageManager.PERMISSION_GRANTED) {
                makeLocationPermissionRequest();
            } else {
                showPolyline();
            }
        } else {
            showPolyline();
        }
}

    @Override
    public void onRequestPermissionsResult(int requestCode, String permissions[], int[] grantResults) {
        switch (requestCode) {
            case LOCATION_PERMISSION_REQUEST_CODE: {
                // If request is cancelled, the result arrays are empty.
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    showPolyline();
                } else {
                }
                return;
            }
        }
    }

}

And don't forget to add

to your AndroidManifest.xml file. And you got something like that: