Question

我在其中一个导航抽屉片段中有谷歌地图，并且不想将其切换为活动。但是，为了简单地在地图上画一条线，我添加了以下代码：

lineOptions = new PolylineOptions()
                .add(new LatLng(33.927085040000001, -118.39129683))
                .add(new LatLng(33.927085969382027, -118.39129820011991))
                .add(new LatLng(33.927081024586677, -118.39130352185116))
                .add(new LatLng(33.927077084498386, -118.39130986277655))
                .add(new LatLng(33.92707405365519, -118.39131496827862))
                .add(new LatLng(33.927066722586623, -118.39131750469446))
                .add(new LatLng(33.927068689880947, -118.39131823397425))
                .add(new LatLng(33.927068030419839, -118.39131796208994))
                .add(new LatLng(33.927065982966624, -118.39132090766913))
                .add(new LatLng(33.927065258415212, -118.3913193654964))
                .width(5)
                .color(Color.RED);
        line = mMap.addPolyline(lineOptions);

然而，它并没有在这两点之间添加线。我从这个问题Drawing a line/path on Google Maps得到了一些代码，并且该人说它有效。所以我不确定我哪里出错了。我在那里有硬编码值的原因是因为在我弄清楚之后，我将从JSON响应中绘制多个路由。以下是所有代码：

public class ThirdFragment extends Fragment implements OnMapReadyCallback {
    View myView;
    private GoogleMap mMap;
    MapFragment mapFrag;
    private Polyline line;

    public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
        myView = inflater.inflate(R.layout.third_layout, container, false);
        return myView;
    }

    @Override
    public void onViewCreated(View view, Bundle savedInstanceState) {
        super.onViewCreated(view, savedInstanceState);

        mapFrag = (MapFragment) getChildFragmentManager().findFragmentById(R.id.map);
        mapFrag.getMapAsync(this);
        //mapFrag.onResume();
    }

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


        if (ActivityCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED || ActivityCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
            line = mMap.addPolyline(new PolylineOptions()
                    .add(new LatLng(33.8031, 118.0726), new LatLng(33.9192, 118.4165))
                    .width(5)
                    .color(Color.RED));
            mMap.setMyLocationEnabled(true);
            Criteria criteria = new Criteria();
            LocationManager locationManager = (LocationManager)getActivity().getSystemService(Context.LOCATION_SERVICE);
            String provider = locationManager.getBestProvider(criteria, false);
            Location location = locationManager.getLastKnownLocation(provider);
            double lat =  location.getLatitude();
            double lng = location.getLongitude();
            LatLng coordinate = new LatLng(lat, lng);
            CameraUpdate yourLocation = CameraUpdateFactory.newLatLngZoom(coordinate, 13);
            mMap.animateCamera(yourLocation);


        } else {
            final AlertDialog alertDialogGPS = new AlertDialog.Builder(getActivity()).create();

            alertDialogGPS.setTitle("Info");
            alertDialogGPS.setMessage("Looks like you have not given GPS permissions. Please give GPS permissions and return back to the app.");
            alertDialogGPS.setIcon(android.R.drawable.ic_dialog_alert);
            alertDialogGPS.setButton("OK", new DialogInterface.OnClickListener() {
                public void onClick(DialogInterface dialog, int which) {

                    Intent intentSettings = new Intent(Settings.ACTION_APPLICATION_SETTINGS);
                    startActivity(intentSettings);
                    alertDialogGPS.dismiss();
                }

            });

            alertDialogGPS.show();
        }

    }
    @Override
    public void onResume() {
        super.onResume();
        if (ActivityCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED || ActivityCompat.checkSelfPermission(getActivity(), Manifest.permission.ACCESS_COARSE_LOCATION) == PackageManager.PERMISSION_GRANTED) {

            mapFrag.getMapAsync(this);
        }
        else {
        }
    }
}

Answer 1

我认为添加列表不是最好的方法来调用... 直接来自官方指南：

PolylineOptions rectOptions = new PolylineOptions()
        .add(new LatLng(37.35, -122.0))
        .add(new LatLng(37.45, -122.0))  // North of the previous point, but at the same longitude
        .add(new LatLng(37.45, -122.2))  // Same latitude, and 30km to the west
        .add(new LatLng(37.35, -122.2))  // Same longitude, and 16km to the south
        .add(new LatLng(37.35, -122.0)); // Closes the polyline.

// Get back the mutable Polyline
Polyline polyline = myMap.addPolyline(rectOptions);

如您所见，使用add函数添加每个点。关于long的大小，你可以把你想要的任何东西，gmaps将它想要的小数点（大约第5个数字）。试试这个，然后尝试更改坐标。记住Lat是Y轴（非洲是〜负lat，值为-90到90），Lon是X轴（USA是负lon，值从-180到180）。

未在Google地图上绘制线条

1 个答案: