Android 我没有'；在我的碎片里找不到蓝线的方向

**此代码将在

两点之间绘制一条路径。代码中给出了这一点。我试了很多次，但都没有找到路线。我为
多段线添加了
code
，但它没有
绘制它**

  @Override
            public void onLocationChanged(Location location) {
                mLastLocation = location;
                if (mCurrLocationMarker != null) {
                    mCurrLocationMarker.remove();
                }
                LatLng latLng = new LatLng(location.getLatitude(), location.getLongitude());
                markerOptions = new MarkerOptions();
                markerOptions.position(latLng);
                markerOptions.title("Current Position");
                // markerOptions.icon(BitmapDescriptorFactory.defaultMarker(BitmapDescriptorFactory.HUE_MAGENTA));
                markerOptions.icon(BitmapDescriptorFactory.fromResource(R.drawable.source_pin));mCurrLocationMarker = mGoogleMap.addMarker(markerOptions);
                Log.d("Current", "" + mCurrLocationMarker);

                if(first)
                {
                    mGoogleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(latLng,15));

                    first = false;
                }
                else{

                }

        if (latLngDestination!=null) {
             markerOptions1 = new MarkerOptions();
            markerOptions1.position(latLngDestination);
            markerOptions1.title("Destination");
                markerOptions1.icon(BitmapDescriptorFactory.fromResource(R.drawable.destination_pin));
            mDestinationMarker = mGoogleMap.addMarker(markerOptions1);
            Log.d("Destinantion", "" + mDestinationMarker);
        }
            }

            @Override
            public void onClick(View v) {

            }

            @Override
            public void onConnected(Bundle bundle) {
                mLocationRequest = new LocationRequest();
                mLocationRequest.setInterval(1000);
                mLocationRequest.setFastestInterval(1000);
                mLocationRequest.setPriority(LocationRequest.PRIORITY_BALANCED_POWER_ACCURACY);
                if (ContextCompat.checkSelfPermission(getActivity(),
                        Manifest.permission.ACCESS_FINE_LOCATION)
                        == PackageManager.PERMISSION_GRANTED) {
                    LocationServices.FusedLocationApi.requestLocationUpdates(mGoogleApiClient, mLocationRequest, this);
                }
            }

            @Override
            public void onConnectionSuspended(int i) {

            }

            @Override
            public void onConnectionFailed(@NonNull ConnectionResult connectionResult) {

            }



            private String getUrl(LatLng origin, LatLng dest, String directionMode) {
                // Origin of route
                String str_origin = "origin=" + origin.latitude + "," + origin.longitude;
                // Destination of route
                String str_dest = "destination=" + dest.latitude + "," + dest.longitude;
                // Mode
                String mode = "mode=" + directionMode;
                // Building the parameters to the web service
                String parameters = str_origin + "&" + str_dest + "&" + mode;
                // Output format
                String output = "json";
                // Building the url to the web service
                String url = "https://maps.googleapis.com/maps/api/directions/" + output + "?" + parameters + "&key=" + getString(R.string.google_api_key);
                return url;
            }

**以下是在点中添加标记的代码**

            @Override
            public void onMapReady(final GoogleMap googleMap) {
                try {
                    MapsInitializer.initialize(mContext);
                } catch (Exception e) {
                    e.printStackTrace();
                }
                mGoogleMap = googleMap;

                mGoogleMap.setMapType(GoogleMap.MAP_TYPE_TERRAIN);

                //Initialize Google Play Services
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.N) {
                    if (ContextCompat.checkSelfPermission(mContext,
                            Manifest.permission.ACCESS_FINE_LOCATION)
                            == PackageManager.PERMISSION_GRANTED) {
                        //Location Permission already granted
                        buildGoogleApiClient();
                        mGoogleMap.setMyLocationEnabled(true);
                    } else {
                        //Request Location Permission
                        checkLocationPermission();

                    }
                } else {
                    buildGoogleApiClient();
                    mGoogleMap.setMyLocationEnabled(true);
                }


                try {
                    mGoogleMap.setOnMapLoadedCallback(new GoogleMap.OnMapLoadedCallback() {
                        @Override
                        public void onMapLoaded() {
                            mGoogleMap.getUiSettings().setZoomControlsEnabled(true);


                        }
                    });


                } catch (NumberFormatException e) {
                    e.printStackTrace();
                }


            }

            public static final int MY_PERMISSIONS_REQUEST_LOCATION = 99;