Android Polyline 没有正确绘制路线

Question

阅读@Akexorcist 在 Get driving directions using Google Maps API v2 上的回答后，我实现了他们的解决方案，以使用多段线绘制从调用 maps.googleapis.com 返回的路线。但是，即使它编译并且没有崩溃，折线也没有显示。

我的主课:

package com.example.robertloggia.test1;

import android.app.Activity;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Path;
import android.location.Criteria;
import android.os.Bundle;
import android.widget.Toast;
import com.google.android.gms.common.api.GoogleApiClient;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.MapFragment;
import com.google.android.gms.maps.MapView;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.CameraPosition;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.Marker;
import com.google.android.gms.maps.model.MarkerOptions;
import android.support.v4.app.FragmentActivity;
import android.location.Location;
import android.location.LocationListener;
import android.location.LocationManager;
import com.google.android.gms.common.api.GoogleApiClient.ConnectionCallbacks;
import com.google.android.gms.common.api.GoogleApiClient.OnConnectionFailedListener;
import com.google.android.gms.maps.model.PolylineOptions;
import com.google.android.gms.maps.model.Polyline;
import android.support.v4.app.FragmentActivity;

import org.w3c.dom.Document;

import java.util.ArrayList;

/**
 * Created by RobertLoggia on 5/28/15.
 */



public class BusTrackingActivity extends Activity{



    private LocationManager mLocationManager = null;
    private GoogleApiClient mGoogleApiClient;

    // Constant for defining latitude and longitude
    static final LatLng DerekPos = new LatLng(40 , -79);

    // GoogleMap class
    private GoogleMap googleMap;

    String routeNumber;
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_bustracking);

        //Get information from main activity
        Bundle extras = getIntent().getExtras();
        if (extras != null) {
            routeNumber = extras.getString("routeNumber");
        }
        Toast.makeText(BusTrackingActivity.this, routeNumber, Toast.LENGTH_SHORT).show();

        try {
            if (googleMap == null) {
                googleMap = ((MapFragment) getFragmentManager().
                        findFragmentById(R.id.map)).getMap();
            }


            //Maps Settings
            googleMap.setMapType(GoogleMap.MAP_TYPE_NORMAL);
            googleMap.setMyLocationEnabled(true);// Place dot on current location
            googleMap.setTrafficEnabled(false);// Turns traffic layer on
            googleMap.setIndoorEnabled(true);// Enables indoor maps
            googleMap.setBuildingsEnabled(true);// Turns on 3D buildings
            googleMap.getUiSettings().setZoomControlsEnabled(true);// Show Zoom buttons


            // Create a marker in the map at a given position with a title
            Marker marker = googleMap.addMarker(new MarkerOptions().
                    position(DerekPos).title("Hello"));


            //Location myLocation = googleMap.getMyLocation();


            //Zoom into map at current location
            LocationManager locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
            Criteria criteria = new Criteria();

            Location location = locationManager.getLastKnownLocation(locationManager.getBestProvider(criteria, false));
            if (location != null) {
                googleMap.animateCamera(CameraUpdateFactory.newLatLngZoom(
                        new LatLng(location.getLatitude(), location.getLongitude()), 13));

                CameraPosition cameraPosition = new CameraPosition.Builder()
                        .target(new LatLng(location.getLatitude(), location.getLongitude()))      // Sets the center of the map to location user
                        .zoom(16)                   // Sets the zoom
                        .bearing(90)                // Sets the orientation of the camera to east
                        .tilt(40)                   // Sets the tilt of the camera to 30 degrees
                        .build();                   // Creates a CameraPosition from the builder
                googleMap.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));




//                Polyline line = googleMap.addPolyline(new PolylineOptions()
//                        .add(new LatLng(location.getLatitude(), location.getLongitude()), new LatLng(41.829548, -71.387993))
//                        .width(5)
//                        .color(Color.RED));



                LatLng fromPosition = new LatLng(41.82861033, -71.38920772);
                LatLng toPosition = new LatLng(41.828777, -71.388499);


                Test md = new Test();
                Document doc = md.getDocument(fromPosition, toPosition, Test.MODE_WALKING);
                ArrayList<LatLng> directionPoint = md.getDirection(doc);
                PolylineOptions rectLine = new PolylineOptions().width(3).color(Color.RED);

                for(int i = 0 ; i < directionPoint.size() ; i++) {
                    rectLine.add(directionPoint.get(i));
                }
                googleMap.addPolyline(rectLine);

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

    }
}

测试类

package com.example.robertloggia.test1;

/**
 * Created by RobertLoggia on 5/29/15.
 */

import java.io.InputStream;
import java.util.ArrayList;

import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;

import org.apache.http.HttpResponse;
import org.apache.http.client.HttpClient;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.BasicHttpContext;
import org.apache.http.protocol.HttpContext;
import org.w3c.dom.Document;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;

import com.google.android.gms.maps.model.LatLng;

import android.content.Context;
import android.util.Log;
public class Test {
    public final static String MODE_DRIVING = "driving";
    public final static String MODE_WALKING = "walking";

    public Test() { }

    public Document getDocument(LatLng start, LatLng end, String mode) {
        String url = "http://maps.googleapis.com/maps/api/directions/xml?"
                + "origin=" + start.latitude + "," + start.longitude
                + "&destination=" + end.latitude + "," + end.longitude
                + "&sensor=false&units=metric&mode="+mode;

        try {
            HttpClient httpClient = new DefaultHttpClient();
            HttpContext localContext = new BasicHttpContext();
            HttpPost httpPost = new HttpPost(url);
            HttpResponse response = httpClient.execute(httpPost, localContext);
            InputStream in = response.getEntity().getContent();
            DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
            Document doc = builder.parse(in);
            return doc;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    public String getDurationText (Document doc) {
        NodeList nl1 = doc.getElementsByTagName("duration");
        Node node1 = nl1.item(nl1.getLength() - 1);
        NodeList nl2 = node1.getChildNodes();
        Node node2 = nl2.item(getNodeIndex(nl2, "text"));
        Log.i("DurationText", node2.getTextContent());
        return node2.getTextContent();
    }

    public int getDurationValue (Document doc) {
        NodeList nl1 = doc.getElementsByTagName("duration");
        Node node1 = nl1.item(nl1.getLength() - 1);
        NodeList nl2 = node1.getChildNodes();
        Node node2 = nl2.item(getNodeIndex(nl2, "value"));
        Log.i("DurationValue", node2.getTextContent());
        return Integer.parseInt(node2.getTextContent());
    }

    public String getDistanceText (Document doc) {
        NodeList nl1 = doc.getElementsByTagName("distance");
        Node node1 = nl1.item(nl1.getLength() - 1);
        NodeList nl2 = node1.getChildNodes();
        Node node2 = nl2.item(getNodeIndex(nl2, "text"));
        Log.i("DistanceText", node2.getTextContent());
        return node2.getTextContent();
    }

    public int getDistanceValue (Document doc) {
        NodeList nl1 = doc.getElementsByTagName("distance");
        Node node1 = nl1.item(nl1.getLength() - 1);
        NodeList nl2 = node1.getChildNodes();
        Node node2 = nl2.item(getNodeIndex(nl2, "value"));
        Log.i("DistanceValue", node2.getTextContent());
        return Integer.parseInt(node2.getTextContent());
    }

    public String getStartAddress (Document doc) {
        NodeList nl1 = doc.getElementsByTagName("start_address");
        Node node1 = nl1.item(0);
        Log.i("StartAddress", node1.getTextContent());
        return node1.getTextContent();
    }

    public String getEndAddress (Document doc) {
        NodeList nl1 = doc.getElementsByTagName("end_address");
        Node node1 = nl1.item(0);
        Log.i("StartAddress", node1.getTextContent());
        return node1.getTextContent();
    }

    public String getCopyRights (Document doc) {
        NodeList nl1 = doc.getElementsByTagName("copyrights");
        Node node1 = nl1.item(0);
        Log.i("CopyRights", node1.getTextContent());
        return node1.getTextContent();
    }

    public ArrayList<LatLng> getDirection (Document doc) {
        NodeList nl1, nl2, nl3;
        ArrayList<LatLng> listGeopoints = new ArrayList<LatLng>();
        nl1 = doc.getElementsByTagName("step");
        if (nl1.getLength() > 0) {
            for (int i = 0; i < nl1.getLength(); i++) {
                Node node1 = nl1.item(i);
                nl2 = node1.getChildNodes();

                Node locationNode = nl2.item(getNodeIndex(nl2, "start_location"));
                nl3 = locationNode.getChildNodes();
                Node latNode = nl3.item(getNodeIndex(nl3, "lat"));
                double lat = Double.parseDouble(latNode.getTextContent());
                Node lngNode = nl3.item(getNodeIndex(nl3, "lng"));
                double lng = Double.parseDouble(lngNode.getTextContent());
                listGeopoints.add(new LatLng(lat, lng));

                locationNode = nl2.item(getNodeIndex(nl2, "polyline"));
                nl3 = locationNode.getChildNodes();
                latNode = nl3.item(getNodeIndex(nl3, "points"));
                ArrayList<LatLng> arr = decodePoly(latNode.getTextContent());
                for(int j = 0 ; j < arr.size() ; j++) {
                    listGeopoints.add(new LatLng(arr.get(j).latitude, arr.get(j).longitude));
                }

                locationNode = nl2.item(getNodeIndex(nl2, "end_location"));
                nl3 = locationNode.getChildNodes();
                latNode = nl3.item(getNodeIndex(nl3, "lat"));
                lat = Double.parseDouble(latNode.getTextContent());
                lngNode = nl3.item(getNodeIndex(nl3, "lng"));
                lng = Double.parseDouble(lngNode.getTextContent());
                listGeopoints.add(new LatLng(lat, lng));
            }
        }

        return listGeopoints;
    }

    private int getNodeIndex(NodeList nl, String nodename) {
        for(int i = 0 ; i < nl.getLength() ; i++) {
            if(nl.item(i).getNodeName().equals(nodename))
                return i;
        }
        return -1;
    }

    private ArrayList<LatLng> decodePoly(String encoded) {
        ArrayList<LatLng> poly = new ArrayList<LatLng>();
        int index = 0, len = encoded.length();
        int lat = 0, lng = 0;
        while (index < len) {
            int b, shift = 0, result = 0;
            do {
                b = encoded.charAt(index++) - 63;
                result |= (b & 0x1f) << shift;
                shift += 5;
            } while (b >= 0x20);
            int dlat = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
            lat += dlat;
            shift = 0;
            result = 0;
            do {
                b = encoded.charAt(index++) - 63;
                result |= (b & 0x1f) << shift;
                shift += 5;
            } while (b >= 0x20);
            int dlng = ((result & 1) != 0 ? ~(result >> 1) : (result >> 1));
            lng += dlng;

            LatLng position = new LatLng((double) lat / 1E5, (double) lng / 1E5);
            poly.add(position);
        }
        return poly;
    }

}

我的activity_bustracking.xml( map 显示完全正常，并且按照应有的方式呈现，只是没有显示多段线)

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    xmlns:map="http://schemas.android.com/apk/res-auto"
    android:orientation="vertical" android:layout_width="match_parent"
    android:layout_height="match_parent">

    <fragment
        android:id="@+id/map"
        android:name="com.google.android.gms.maps.MapFragment"
        android:layout_width="match_parent"
        android:layout_height="match_parent"/>
</LinearLayout>

为了显示折线，我需要更改或添加什么？

Answer 1

最后想出解决办法，代码如下:

请注意，您需要导入包含 4 个文件的库:BitmapRequest.java、GoogleDirection.java、GooglePlaceSearch.java 和 PlaceType.java 来自 here .

BusTrakingActivity.java

public class BusTrackingActivity extends FragmentActivity {
    LatLng start = new LatLng(41.82861033, -71.38920772);
    LatLng end = new LatLng(41.828777, -71.388499);

    GoogleMap mMap;
    GoogleDirection gd;
    Document mDoc;

    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_bustracking);

        mMap = ((SupportMapFragment) getSupportFragmentManager()
                .findFragmentById(R.id.map)).getMap();

        mMap.animateCamera(CameraUpdateFactory.newLatLngZoom(start, 15));

        gd = new GoogleDirection(this);
        gd.setOnDirectionResponseListener(new GoogleDirection.OnDirectionResponseListener() {
            public void onResponse(String status, Document doc, GoogleDirection gd) {
                mDoc = doc;
                mMap.addPolyline(gd.getPolyline(doc, 3, Color.RED));
                mMap.addMarker(new MarkerOptions().position(start)
                        .icon(BitmapDescriptorFactory.defaultMarker(
                                BitmapDescriptorFactory.HUE_GREEN)));

                mMap.addMarker(new MarkerOptions().position(end)
                        .icon(BitmapDescriptorFactory.defaultMarker(
                                BitmapDescriptorFactory.HUE_GREEN)));

            }
        });

        gd.setLogging(true);
        gd.request(start, end, GoogleDirection.MODE_DRIVING);
    }



    public void onPause() {
        super.onPause();
        gd.cancelAnimated();
    }
}

和activity_bustracking.xml:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
              android:orientation="vertical" android:layout_width="match_parent"
              android:layout_height="match_parent">

    <fragment
        android:id="@+id/map"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:name="com.google.android.gms.maps.SupportMapFragment" />

</LinearLayout>