我能够在android map v2上的两个地理点之间使用折线绘制单一路线。但我不知道如何从源到目的地绘制多条路线我试图添加“alternatives = true”但仍然只在地图上获得一条路线。有人请帮我解决这个问题，因为我在网上做了很多研究，但仍然无法找到任何容易理解的解决方案。
GoogleDirection.java
@SuppressLint("NewApi")
public class GoogleDirection {
public GoogleDirection(Context context) {
mContext = context;
}
public String request(LatLng start, LatLng end, String mode) {
final 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 + "alternatives=true";
if(isLogging)
Log.i("GoogleDirection", "URL : " + url);
new RequestTask().execute(new String[]{ url });
return url;
}
private class RequestTask extends AsyncTask<String, Void, Document> {
protected Document doInBackground(String... url) {
try {
HttpClient httpClient = new DefaultHttpClient();
HttpContext localContext = new BasicHttpContext();
HttpPost httpPost = new HttpPost(url[0]);
HttpResponse response = httpClient.execute(httpPost, localContext);
InputStream in = response.getEntity().getContent();
DocumentBuilder builder = DocumentBuilderFactory.newInstance().newDocumentBuilder();
return builder.parse(in);
} catch (IOException e) {
e.printStackTrace();
} catch (ParserConfigurationException e) {
e.printStackTrace();
} catch (SAXException e) {
e.printStackTrace();
}
return null;
}
protected void onPostExecute(Document doc) {
super.onPostExecute(doc);
if(mDirectionListener != null)
mDirectionListener.onResponse(getStatus(doc), doc, GoogleDirection.this);
}
private String getStatus(Document doc) {
NodeList nl1 = doc.getElementsByTagName("status");
Node node1 = nl1.item(0);
if(isLogging)
Log.i("GoogleDirection", "Status : " + node1.getTextContent());
return node1.getTextContent();
}
}
public void setLogging(boolean state) {
isLogging = state;
}
public String getStatus(Document doc) {
NodeList nl1 = doc.getElementsByTagName("status");
Node node1 = nl1.item(0);
if(isLogging)
Log.i("GoogleDirection", "Status : " + node1.getTextContent());
return node1.getTextContent();
}
public String[] getDurationText(Document doc) {
NodeList nl1 = doc.getElementsByTagName("duration");
String[] arr_str = new String[nl1.getLength() - 1];
for(int i = 0 ; i < nl1.getLength() - 1 ; i++) {
Node node1 = nl1.item(i);
NodeList nl2 = node1.getChildNodes();
Node node2 = nl2.item(getNodeIndex(nl2, "text"));
arr_str[i] = node2.getTextContent();
if(isLogging)
Log.i("GoogleDirection", "DurationText : " + node2.getTextContent());
}
return arr_str;
}
public int[] getDurationValue(Document doc) {
NodeList nl1 = doc.getElementsByTagName("duration");
int[] arr_int = new int[nl1.getLength() - 1];
for(int i = 0 ; i < nl1.getLength() - 1 ; i++) {
Node node1 = nl1.item(i);
NodeList nl2 = node1.getChildNodes();
Node node2 = nl2.item(getNodeIndex(nl2, "value"));
arr_int[i] = Integer.parseInt(node2.getTextContent());
if(isLogging)
Log.i("GoogleDirection", "Duration : " + node2.getTextContent());
}
return arr_int;
}
public String getTotalDurationText(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"));
if(isLogging)
Log.i("GoogleDirection", "TotalDuration : " + node2.getTextContent());
return node2.getTextContent();
}
public int getTotalDurationValue(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"));
if(isLogging)
Log.i("GoogleDirection", "TotalDuration : " + node2.getTextContent());
return Integer.parseInt(node2.getTextContent());
}
public String[] getDistanceText(Document doc) {
NodeList nl1 = doc.getElementsByTagName("distance");
String[] arr_str = new String[nl1.getLength() - 1];
for(int i = 0 ; i < nl1.getLength() - 1 ; i++) {
Node node1 = nl1.item(i);
NodeList nl2 = node1.getChildNodes();
Node node2 = nl2.item(getNodeIndex(nl2, "text"));
arr_str[i] = node2.getTextContent();
if(isLogging)
Log.i("GoogleDirection", "DurationText : " + node2.getTextContent());
}
return arr_str;
}
public int[] getDistanceValue(Document doc) {
NodeList nl1 = doc.getElementsByTagName("distance");
int[] arr_int = new int[nl1.getLength() - 1];
for(int i = 0 ; i < nl1.getLength() - 1 ; i++) {
Node node1 = nl1.item(i);
NodeList nl2 = node1.getChildNodes();
Node node2 = nl2.item(getNodeIndex(nl2, "value"));
arr_int[i] = Integer.parseInt(node2.getTextContent());
if(isLogging)
Log.i("GoogleDirection", "Duration : " + node2.getTextContent());
}
return arr_int;
}
public String getTotalDistanceText(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"));
if(isLogging)
Log.i("GoogleDirection", "TotalDuration : " + node2.getTextContent());
return node2.getTextContent();
}
public int getTotalDistanceValue(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"));
if(isLogging)
Log.i("GoogleDirection", "TotalDuration : " + node2.getTextContent());
return Integer.parseInt(node2.getTextContent());
}
public String getStartAddress(Document doc) {
NodeList nl1 = doc.getElementsByTagName("start_address");
Node node1 = nl1.item(0);
if(isLogging)
Log.i("GoogleDirection", "StartAddress : " + node1.getTextContent());
return node1.getTextContent();
}
public String getEndAddress(Document doc) {
NodeList nl1 = doc.getElementsByTagName("end_address");
Node node1 = nl1.item(0);
if(isLogging)
Log.i("GoogleDirection", "StartAddress : " + node1.getTextContent());
return node1.getTextContent();
}
public String getCopyRights(Document doc) {
NodeList nl1 = doc.getElementsByTagName("copyrights");
Node node1 = nl1.item(0);
if(isLogging)
Log.i("GoogleDirection", "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;
}
public ArrayList<LatLng> getSection(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, "end_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));
}
}
return listGeopoints;
}
public PolylineOptions getPolyline(Document doc, int width, int color) {
ArrayList<LatLng> arr_pos = getDirection(doc);
PolylineOptions rectLine = new PolylineOptions().width(dpToPx(width)).color(color);
for(int i = 0 ; i < arr_pos.size() ; i++)
rectLine.add(arr_pos.get(i));
return rectLine;
}
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;
}
private int dpToPx(int dp) {
DisplayMetrics displayMetrics = mContext.getResources().getDisplayMetrics();
int px = Math.round(dp * (displayMetrics.xdpi / DisplayMetrics.DENSITY_DEFAULT));
return px;
}
public void setOnDirectionResponseListener(OnDirectionResponseListener listener) {
mDirectionListener = listener;
}
public void setOnAnimateListener(OnAnimateListener listener) {
mAnimateListener = listener;
}
public interface OnDirectionResponseListener {
public void onResponse(String status, Document doc, GoogleDirection gd);
}
public interface OnAnimateListener {
public void onFinish();
public void onStart();
public void onProgress(int progress, int total);
}
public void animateDirection(GoogleMap gm, ArrayList<LatLng> direction, int speed
, boolean cameraLock, boolean isCameraTilt, boolean isCameraZoom
, boolean drawMarker, MarkerOptions mo, boolean flatMarker
, boolean drawLine, PolylineOptions po) {
if(direction.size() > 1) {
isAnimated = true;
animatePositionList = direction;
animateSpeed = speed;
this.drawMarker = drawMarker;
this.drawLine = drawLine;
this.flatMarker = flatMarker;
this.isCameraTilt = isCameraTilt;
this.isCameraZoom = isCameraZoom;
step = 0;
this.cameraLock = cameraLock;
this.gm = gm;
setCameraUpdateSpeed(speed);
beginPosition = animatePositionList.get(step);
endPosition = animatePositionList.get(step + 1);
animateMarkerPosition = beginPosition;
if(mAnimateListener != null)
mAnimateListener.onProgress(step, animatePositionList.size());
if(cameraLock) {
float bearing = getBearing(beginPosition, endPosition);
CameraPosition.Builder cameraBuilder = new CameraPosition.Builder()
.target(animateMarkerPosition).bearing(bearing);
if(isCameraTilt)
cameraBuilder.tilt(90);
else
cameraBuilder.tilt(gm.getCameraPosition().tilt);
if(isCameraZoom)
cameraBuilder.zoom(zoom);
else
cameraBuilder.zoom(gm.getCameraPosition().zoom);
CameraPosition cameraPosition = cameraBuilder.build();
gm.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));
}
if(drawMarker) {
if(mo != null)
animateMarker = gm.addMarker(mo.position(beginPosition));
else
animateMarker = gm.addMarker(new MarkerOptions().position(beginPosition));
if(flatMarker) {
animateMarker.setFlat(true);
float rotation = getBearing(animateMarkerPosition, endPosition) + 180;
animateMarker.setRotation(rotation);
}
}
if(drawLine) {
if(po != null)
animateLine = gm.addPolyline(po.add(beginPosition)
.add(beginPosition).add(endPosition)
.width(dpToPx((int)po.getWidth())));
else
animateLine = gm.addPolyline(new PolylineOptions()
.width(dpToPx(5)));
}
new Handler().postDelayed(r, speed);
if(mAnimateListener != null)
mAnimateListener.onStart();
}
}
public void cancelAnimated() {
isAnimated = false;
}
public boolean isAnimated() {
return isAnimated;
}
private Runnable r = new Runnable() {
public void run() {
animateMarkerPosition = getNewPosition(animateMarkerPosition, endPosition);
if(drawMarker)
animateMarker.setPosition(animateMarkerPosition);
if(drawLine) {
List<LatLng> points = animateLine.getPoints();
points.add(animateMarkerPosition);
animateLine.setPoints(points);
}
if((animateMarkerPosition.latitude == endPosition.latitude
&& animateMarkerPosition.longitude == endPosition.longitude)) {
if(step == animatePositionList.size() - 2) {
isAnimated = false;
totalAnimateDistance = 0;
if(mAnimateListener != null)
mAnimateListener.onFinish();
} else {
step++;
beginPosition = animatePositionList.get(step);
endPosition = animatePositionList.get(step + 1);
animateMarkerPosition = beginPosition;
if(flatMarker && step + 3 < animatePositionList.size() - 1) {
float rotation = getBearing(animateMarkerPosition, animatePositionList.get(step + 3)) + 180;
animateMarker.setRotation(rotation);
}
if(mAnimateListener != null)
mAnimateListener.onProgress(step, animatePositionList.size());
}
}
if(cameraLock && (totalAnimateDistance > animateCamera || !isAnimated)) {
totalAnimateDistance = 0;
float bearing = getBearing(beginPosition, endPosition);
CameraPosition.Builder cameraBuilder = new CameraPosition.Builder()
.target(animateMarkerPosition).bearing(bearing);
if(isCameraTilt)
cameraBuilder.tilt(90);
else
cameraBuilder.tilt(gm.getCameraPosition().tilt);
if(isCameraZoom)
cameraBuilder.zoom(zoom);
else
cameraBuilder.zoom(gm.getCameraPosition().zoom);
CameraPosition cameraPosition = cameraBuilder.build();
gm.animateCamera(CameraUpdateFactory.newCameraPosition(cameraPosition));
}
if(isAnimated) {
new Handler().postDelayed(r, animateSpeed);
}
}
};
public Marker getAnimateMarker() {
return animateMarker;
}
public Polyline getAnimatePolyline() {
return animateLine;
}
private LatLng getNewPosition(LatLng begin, LatLng end) {
double lat = Math.abs(begin.latitude - end.latitude);
double lng = Math.abs(begin.longitude - end.longitude);
double dis = Math.sqrt(Math.pow(lat, 2) + Math.pow(lng, 2));
if(dis >= animateDistance) {
double angle = -1;
if(begin.latitude <= end.latitude && begin.longitude <= end.longitude)
angle = Math.toDegrees(Math.atan(lng / lat));
else if(begin.latitude > end.latitude && begin.longitude <= end.longitude)
angle = (90 - Math.toDegrees(Math.atan(lng / lat))) + 90;
else if(begin.latitude > end.latitude && begin.longitude > end.longitude)
angle = Math.toDegrees(Math.atan(lng / lat)) + 180;
else if(begin.latitude <= end.latitude && begin.longitude > end.longitude)
angle = (90 - Math.toDegrees(Math.atan(lng / lat))) + 270;
double x = Math.cos(Math.toRadians(angle)) * animateDistance;
double y = Math.sin(Math.toRadians(angle)) * animateDistance;
totalAnimateDistance += animateDistance;
double finalLat = begin.latitude + x;
double finalLng = begin.longitude + y;
return new LatLng(finalLat, finalLng);
} else {
return end;
}
}
private float getBearing(LatLng begin, LatLng end) {
double lat = Math.abs(begin.latitude - end.latitude);
double lng = Math.abs(begin.longitude - end.longitude);
if(begin.latitude < end.latitude && begin.longitude < end.longitude)
return (float)(Math.toDegrees(Math.atan(lng / lat)));
else if(begin.latitude >= end.latitude && begin.longitude < end.longitude)
return (float)((90 - Math.toDegrees(Math.atan(lng / lat))) + 90);
else if(begin.latitude >= end.latitude && begin.longitude >= end.longitude)
return (float)(Math.toDegrees(Math.atan(lng / lat)) + 180);
else if(begin.latitude < end.latitude && begin.longitude >= end.longitude)
return (float)((90 - Math.toDegrees(Math.atan(lng / lat))) + 270);
return -1;
}
public void setCameraUpdateSpeed(int speed) {
if(speed == SPEED_VERY_SLOW) {
animateDistance = 0.000005;
animateSpeed = 20;
animateCamera = 0.0004;
zoom = 19;
} else if(speed == SPEED_SLOW) {
animateDistance = 0.00001;
animateSpeed = 20;
animateCamera = 0.0008;
zoom = 18;
} else if(speed == SPEED_NORMAL) {
animateDistance = 0.00005;
animateSpeed = 20;
animateCamera = 0.002;
zoom = 16;
} else if(speed == SPEED_FAST) {
animateDistance = 0.0001;
animateSpeed = 20;
animateCamera = 0.004;
zoom = 15;
} else if(speed == SPEED_VERY_FAST) {
animateDistance = 0.0005;
animateSpeed = 20;
animateCamera = 0.004;
zoom = 13;
} else {
animateDistance = 0.00005;
animateSpeed = 20;
animateCamera = 0.002;
zoom = 16;
}
}
}
MainActivity.java
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_map);
gd = new GoogleDirection(this);
gd.setOnDirectionResponseListener(new OnDirectionResponseListener() {
public void onResponse(String status, Document doc, GoogleDirection gd) {
mDoc = doc;
polyline = mGoogleMap.addPolyline(gd.getPolyline(doc, 10, Color.RED));
}
});
route.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
// TODO Auto-generated method stub
LatLng newLatLong1 = new LatLng(la1d, lo1d);
LatLng newLatLong2 = new LatLng(la2d, lo2d);
gd.setLogging(true);
gd.request(newLatLong2, newLatLong1, GoogleDirection.MODE_DRIVING);
}
});
答案 0 :(得分：2)
您需要使用Google Directions API。只需使用HTTP请求命中给定的URL并获取json响应。此Google服务会计算指定位置之间的路线。
示例代码：
PathGoogleMapActivity.java
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import org.json.JSONObject;
import android.graphics.Color;
import android.os.AsyncTask;
import android.os.Bundle;
import android.support.v4.app.FragmentActivity;
import android.util.Log;
import com.google.android.gms.maps.CameraUpdateFactory;
import com.google.android.gms.maps.GoogleMap;
import com.google.android.gms.maps.SupportMapFragment;
import com.google.android.gms.maps.model.LatLng;
import com.google.android.gms.maps.model.MarkerOptions;
import com.google.android.gms.maps.model.PolylineOptions;
public class PathGoogleMapActivity extends FragmentActivity {
private static final LatLng LOWER_MANHATTAN = new LatLng(40.722543,
-73.998585);
private static final LatLng BROOKLYN_BRIDGE = new LatLng(40.7057, -73.9964);
private static final LatLng WALL_STREET = new LatLng(40.7064, -74.0094);
GoogleMap googleMap;
final String TAG = "PathGoogleMapActivity";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_path_google_map);
SupportMapFragment fm = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
googleMap = fm.getMap();
MarkerOptions options = new MarkerOptions();
options.position(LOWER_MANHATTAN);
options.position(BROOKLYN_BRIDGE);
options.position(WALL_STREET);
googleMap.addMarker(options);
String url = getMapsApiDirectionsUrl();
ReadTask downloadTask = new ReadTask();
downloadTask.execute(url);
googleMap.moveCamera(CameraUpdateFactory.newLatLngZoom(BROOKLYN_BRIDGE,
13));
addMarkers();
}
private String getMapsApiDirectionsUrl() {
String waypoints = "waypoints=optimize:true|"
+ LOWER_MANHATTAN.latitude + "," + LOWER_MANHATTAN.longitude
+ "|" + "|" + BROOKLYN_BRIDGE.latitude + ","
+ BROOKLYN_BRIDGE.longitude + "|" + WALL_STREET.latitude + ","
+ WALL_STREET.longitude;
String sensor = "sensor=false";
String params = waypoints + "&" + sensor;
String output = "json";
String url = "https://maps.googleapis.com/maps/api/directions/"
+ output + "?" + params;
return url;
}
private void addMarkers() {
if (googleMap != null) {
googleMap.addMarker(new MarkerOptions().position(BROOKLYN_BRIDGE)
.title("First Point"));
googleMap.addMarker(new MarkerOptions().position(LOWER_MANHATTAN)
.title("Second Point"));
googleMap.addMarker(new MarkerOptions().position(WALL_STREET)
.title("Third Point"));
}
}
private class ReadTask extends AsyncTask {
@Override
protected String doInBackground(String... url) {
String data = "";
try {
HttpConnection http = new HttpConnection();
data = http.readUrl(url[0]);
} catch (Exception e) {
Log.d("Background Task", e.toString());
}
return data;
}
@Override
protected void onPostExecute(String result) {
super.onPostExecute(result);
new ParserTask().execute(result);
}
}
private class ParserTask extends
AsyncTask>>> {
@Override
protected List>> doInBackground(
String... jsonData) {
JSONObject jObject;
List>> routes = null;
try {
jObject = new JSONObject(jsonData[0]);
PathJSONParser parser = new PathJSONParser();
routes = parser.parse(jObject);
} catch (Exception e) {
e.printStackTrace();
}
return routes;
}
@Override
protected void onPostExecute(List>> routes) {
ArrayList points = null;
PolylineOptions polyLineOptions = null;
// traversing through routes
for (int i = 0; i < routes.size(); i++) {
points = new ArrayList();
polyLineOptions = new PolylineOptions();
List> path = routes.get(i);
for (int j = 0; j < path.size(); j++) {
HashMap point = path.get(j);
double lat = Double.parseDouble(point.get("lat"));
double lng = Double.parseDouble(point.get("lng"));
LatLng position = new LatLng(lat, lng);
points.add(position);
}
polyLineOptions.addAll(points);
polyLineOptions.width(2);
polyLineOptions.color(Color.BLUE);
}
googleMap.addPolyline(polyLineOptions);
}
}
}
HttpConnection.java
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.URL;
import android.util.Log;
public class HttpConnection {
public String readUrl(String mapsApiDirectionsUrl) throws IOException {
String data = "";
InputStream iStream = null;
HttpURLConnection urlConnection = null;
try {
URL url = new URL(mapsApiDirectionsUrl);
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.connect();
iStream = urlConnection.getInputStream();
BufferedReader br = new BufferedReader(new InputStreamReader(
iStream));
StringBuffer sb = new StringBuffer();
String line = "";
while ((line = br.readLine()) != null) {
sb.append(line);
}
data = sb.toString();
br.close();
} catch (Exception e) {
Log.d("Exception while reading url", e.toString());
} finally {
iStream.close();
urlConnection.disconnect();
}
return data;
}
}
PathJSONParser.java
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import com.google.android.gms.maps.model.LatLng;
public class PathJSONParser {
public List>> parse(JSONObject jObject) {
List>> routes = new ArrayList>>();
JSONArray jRoutes = null;
JSONArray jLegs = null;
JSONArray jSteps = null;
try {
jRoutes = jObject.getJSONArray("routes");
/** Traversing all routes */
for (int i = 0; i < jRoutes.length(); i++) {
jLegs = ((JSONObject) jRoutes.get(i)).getJSONArray("legs");
List> path = new ArrayList>();
/** Traversing all legs */
for (int j = 0; j < jLegs.length(); j++) {
jSteps = ((JSONObject) jLegs.get(j)).getJSONArray("steps");
/** Traversing all steps */
for (int k = 0; k < jSteps.length(); k++) {
String polyline = "";
polyline = (String) ((JSONObject) ((JSONObject) jSteps
.get(k)).get("polyline")).get("points");
List list = decodePoly(polyline);
/** Traversing all points */
for (int l = 0; l < list.size(); l++) {
HashMap hm = new HashMap();
hm.put("lat",
Double.toString(((LatLng) list.get(l)).latitude));
hm.put("lng",
Double.toString(((LatLng) list.get(l)).longitude));
path.add(hm);
}
}
routes.add(path);
}
}
} catch (JSONException e) {
e.printStackTrace();
} catch (Exception e) {
}
return routes;
}
/**
* Method Courtesy :
* jeffreysambells.com/2010/05/27
* /decoding-polylines-from-google-maps-direction-api-with-java
* */
private List decodePoly(String encoded) {
List poly = new ArrayList();
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 p = new LatLng((((double) lat / 1E5)),
(((double) lng / 1E5)));
poly.add(p);
}
return poly;
}
}
有关详细信息，请参阅here。