这是一个棘手的问题，一直在敲我的头一天，请帮助。
我使用谷歌地图Apis获得我提供的2个GeoPoints之间的最短行驶距离及其路线，点等，请参阅下面的代码
private JSONObject GetDistance(String src, String dest) throws Exception
{
StringBuilder urlString = new StringBuilder();
urlString.append("http://maps.googleapis.com/maps/api/directions/json?");
urlString.append("origin=");// from
urlString.append(src);
urlString.append("&destination=");// to
urlString.append(dest);
urlString.append("&mode=driving&sensor=true&units=imperial");
// get the JSON And parse it to get the directions data.
HttpURLConnection urlConnection = null;
URL url = null;
url = new URL(urlString.toString());
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.setDoOutput(true);
urlConnection.setDoInput(true);
urlConnection.connect();
InputStream inStream = urlConnection.getInputStream();
BufferedReader bReader = new BufferedReader(new InputStreamReader(inStream));
String temp, response = "";
while ((temp = bReader.readLine()) != null)
{
// Parse data
response += temp;
}
// Close the reader, stream & connection
bReader.close();
inStream.close();
urlConnection.disconnect();
JSONObject object = (JSONObject) new JSONTokener(response).nextValue();
return (object);
}
我还在谷歌地图片段上绘制了2个GeoPoints，我使用了SupportMapFragment，即这个库com.google.android.gms.maps.SupportMapFragment
我想要做的是，我想绘制从上面的getDistance函数获得的路径，它以JSON输出我可以轻松处理的数据。
Here is the JSON object that I get from the getDistance function
{
"status": "OK",
"routes": [
{
"waypoint_order": [],
"summary": "Wilbraham Rd/A6010",
"bounds": {
"southwest": {
"lng": -2.26773,
"lat": 53.4301
},
"northeast": {
"lng": -2.19414,
"lat": 53.45106000000001
}
},
"legs": [
{
"duration": {
"value": 797,
"text": "13 mins"
},
"distance": {
"value": 7289,
"text": "4.5 mi"
},
"end_location": {
"lng": -2.19414,
"lat": 53.43052
},
"start_address": "137 College Road, Manchester, Greater Manchester M16 0AA, UK",
"end_address": "6 Ealing Place, Manchester M19, UK",
"start_location": {
"lng": -2.26773,
"lat": 53.45106000000001
},
"via_waypoint": [],
"steps": [
{
"html_instructions": "Head <b>southeast</b> on <b>College Rd</b> toward <b>Park Dr</b>",
"duration": {
"value": 83,
"text": "1 min"
},
"distance": {
"value": 729,
"text": "0.5 mi"
},
"end_location": {
"lng": -2.25758,
"lat": 53.45005
},
"polyline": {
"points": "ctfeIh|yLrBaEdAoB`@w@N]BKDM@Q@M?]?WC}AAgAGyG?mAI{GG{JM_HAo@"
},
"travel_mode": "DRIVING",
"start_location": {
"lng": -2.26773,
"lat": 53.45106000000001
}
},
{
"html_instructions": "Turn <b>right</b> onto <b>Withington Rd</b>",
"duration": {
"value": 96,
"text": "2 mins"
},
"distance": {
"value": 747,
"text": "0.5 mi"
},
"end_location": {
"lng": -2.25703,
"lat": 53.44339
},
"polyline": {
"points": "ymfeIz|wLJ@v@TL@N?H?HAHCJEXKhAy@JGTEH?|BAzAExAAN?z@Cb@?dA?d@AdFKxCGfCC"
},
"travel_mode": "DRIVING",
"start_location": {
"lng": -2.25758,
"lat": 53.45005
}
},
{
"html_instructions": "Turn <b>left</b> onto <b>Wilbraham Rd/A6010</b>",
"duration": {
"value": 249,
"text": "4 mins"
},
"distance": {
"value": 2565,
"text": "1.6 mi"
},
"end_location": {
"lng": -2.21852,
"lat": 53.44261
},
"polyline": {
"points": "edeeIlywLAsGAgA@}D@m@@{EFqGHcG?]LmGHaFDyD@gB?sC?oDIw@?i@AuACoCKiGWcNe@mQKcEK}DASAe@C{AAcAAq@?_B?mABkALkCFgBF[LsCp@sQFyADmALkDj@wNx@_U@wA"
},
"travel_mode": "DRIVING",
"start_location": {
"lng": -2.25703,
"lat": 53.44339
}
},
{
"html_instructions": "Continue straight onto <b>Moseley Rd/B5093</b><div style=\"font-size:0.9em\">Continue to follow Moseley Rd</div><div style=\"font-size:0.9em\">Go through 1 roundabout</div>",
"duration": {
"value": 100,
"text": "2 mins"
},
"distance": {
"value": 974,
"text": "0.6 mi"
},
"end_location": {
"lng": -2.20411,
"lat": 53.44213000000001
},
"polyline": {
"points": "i_eeIvhpLDsA@a@Ba@D{@JgAPsAVgBHi@De@Fe@Bc@Bk@D{@@_A?qAB}I?gA@oDBmJ@qD?g@@gGBgD@[?Q?MA[AUG]A??AA??AA??AA??A?AA??A?A?AAA?A?A?A?A?A?A?A@??A?A?A@A?A@??A@A@A@?@AYiE"
},
"travel_mode": "DRIVING",
"start_location": {
"lng": -2.21852,
"lat": 53.44261
}
},
{
"html_instructions": "At the roundabout, take the <b>2nd</b> exit onto <b>Kingsway/A34</b>",
"duration": {
"value": 63,
"text": "1 min"
},
"distance": {
"value": 694,
"text": "0.4 mi"
},
"end_location": {
"lng": -2.20629,
"lat": 53.43661
},
"polyline": {
"points": "i|deItnmLC?AAA?AAAAA?AA?AACAAAAAC?AAC?AAC?C?C?CAA?C?C@C?C?A?C@C?C@A?C@A@C?A@A@A@A@A@A@?@A@?@A@?@?B?@@@?@@@?@@@??@@@@@?@@@@@?@@@?@?@@@b@V^VZHDBHBf@Rv@ZLD`@NJDB@h@RrFvBLDhGxBjFdB"
},
"travel_mode": "DRIVING",
"start_location": {
"lng": -2.20411,
"lat": 53.44213000000001
}
},
{
"html_instructions": "Turn <b>left</b> onto <b>Grangethorpe Dr</b>",
"duration": {
"value": 56,
"text": "1 min"
},
"distance": {
"value": 415,
"text": "0.3 mi"
},
"end_location": {
"lng": -2.20015,
"lat": 53.43616
},
"polyline": {
"points": "yyceIh|mL\\aCBUBa@RcCFc@FcAHiB@MReRM}@AI"
},
"travel_mode": "DRIVING",
"start_location": {
"lng": -2.20629,
"lat": 53.43661
}
},
{
"html_instructions": "Continue onto <b>Crossley Rd</b>",
"duration": {
"value": 45,
"text": "1 min"
},
"distance": {
"value": 394,
"text": "0.2 mi"
},
"end_location": {
"lng": -2.19433,
"lat": 53.43562000000001
},
"polyline": {
"points": "_wceI|ulLGyCBY@GJs@L}@BaA?GFqCBiBDkB@CLkBPkBRsCF{@"
},
"travel_mode": "DRIVING",
"start_location": {
"lng": -2.20015,
"lat": 53.43616
}
},
{
"html_instructions": "Turn <b>right</b> onto <b>Errwood Rd</b>",
"duration": {
"value": 60,
"text": "1 min"
},
"distance": {
"value": 607,
"text": "0.4 mi"
},
"end_location": {
"lng": -2.19615,
"lat": 53.43027000000001
},
"polyline": {
"points": "ssceIpqkL`GtA`B`@xCt@z@Th@H|EnAjFlA"
},
"travel_mode": "DRIVING",
"start_location": {
"lng": -2.19433,
"lat": 53.43562000000001
}
},
{
"html_instructions": "Take the 2nd <b>left</b> onto <b>Watford Rd</b>",
"duration": {
"value": 12,
"text": "1 min"
},
"distance": {
"value": 83,
"text": "272 ft"
},
"end_location": {
"lng": -2.19492,
"lat": 53.4301
},
"polyline": {
"points": "erbeI||kL`@uF"
},
"travel_mode": "DRIVING",
"start_location": {
"lng": -2.19615,
"lat": 53.43027000000001
}
},
{
"html_instructions": "Turn <b>left</b> onto <b>Eastern Cir</b>",
"duration": {
"value": 20,
"text": "1 min"
},
"distance": {
"value": 65,
"text": "213 ft"
},
"end_location": {
"lng": -2.19415,
"lat": 53.43037
},
"polyline": {
"points": "cqbeIfukLWWIMKUG_@AU@g@"
},
"travel_mode": "DRIVING",
"start_location": {
"lng": -2.19492,
"lat": 53.4301
}
},
{
"html_instructions": "Take the 2nd <b>left</b> onto <b>Ealing Pl</b>",
"duration": {
"value": 13,
"text": "1 min"
},
"distance": {
"value": 16,
"text": "52 ft"
},
"end_location": {
"lng": -2.19414,
"lat": 53.43052
},
"polyline": {
"points": "yrbeIlpkL]A"
},
"travel_mode": "DRIVING",
"start_location": {
"lng": -2.19415,
"lat": 53.43037
}
}
]
}
],
"warnings": [],
"overview_polyline": {
"points": "ctfeIh|yLxDqHp@uAHYB_@E{EGgJQwSOoIbAVp@?TIXKhAy@`@MfCA`GKhB?jGM`HKC{ILyUHaHVoNFaH?cIIw@?i@EeFc@mVq@qWSsICcHPwEFgBF[~@gVLgDx@cTx@_U@wAFuBH}A\\{C`@qCLkAFoAF{BBoLFwW@oHDcECqAK_@CCCM?G@E@GDEBAYiEC?CACCEGEICMAMD[BKFGFCHAFBDDDF@Fd@X^VZHNF~An@~@\\|GjCvG~BjFdB\\aCFw@ZgDPmDTsROgAGyCBYL{@L}@BaAFyCHuENoBd@_GF{@`GtAzFvAdB^|EnAjFlA`@uFWWUc@Iu@@g@]A"
},
"copyrights": "Map data ©2013 Google"
}
]
}
请帮助，我真的迷失在这里。
答案 0 :(得分：6)
请看一下我在此处提供的代码，其中一篇文章是从Google Direction API创建Polyline的，如果您想从其他来源获取数据，可以更改获取数据的类，但这就是您的操作方法它。创建一个负责获取方向和解析的类：
public class GMapV2Direction {
public final static String MODE_DRIVING = "driving";
public final static String MODE_WALKING = "walking";
public GMapV2Direction() { }
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(0);
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(0);
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(0);
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(0);
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;
}
}
创建一个getDirections AsyncTask：
public class GetDirectionsAsyncTask extends AsyncTask<Map<String, String>, Object, ArrayList<LatLng>> {
public static final String USER_CURRENT_LAT = "user_current_lat";
public static final String USER_CURRENT_LONG = "user_current_long";
public static final String DESTINATION_LAT = "destination_lat";
public static final String DESTINATION_LONG = "destination_long";
public static final String DIRECTIONS_MODE = "directions_mode";
private MapFragmentActivity activity;
private String url;
private Exception exception;
private Dialog progressDialog;
public GetDirectionsAsyncTask(MapFragmentActivity activity /*String url*/)
{
super();
this.activity = activity;
// this.url = url;
}
public void onPreExecute() {
progressDialog = DialogUtils.createProgressDialog(activity, activity.getString(R.string.get_data_dialog_message));
progressDialog.show();
}
@Override
public void onPostExecute(ArrayList<LatLng> result) {
progressDialog.dismiss();
if (exception == null) {
activity.handleGetDirectionsResult(result);
} else {
processException();
}
}
@Override
protected ArrayList<LatLng> doInBackground(Map<String, String>... params) {
Map<String, String> paramMap = params[0];
try{
LatLng fromPosition = new LatLng(Double.valueOf(paramMap.get(USER_CURRENT_LAT)) , Double.valueOf(paramMap.get(USER_CURRENT_LONG)));
LatLng toPosition = new LatLng(Double.valueOf(paramMap.get(DESTINATION_LAT)) , Double.valueOf(paramMap.get(DESTINATION_LONG)));
GMapV2Direction md = new GMapV2Direction();
Document doc = md.getDocument(fromPosition, toPosition, paramMap.get(DIRECTIONS_MODE));
ArrayList<LatLng> directionPoints = md.getDirection(doc);
return directionPoints;
}
catch (Exception e) {
exception = e;
return null;
}
}
private void processException() {
Toast.makeText(activity, activity.getString(R.string.error_when_retrieving_data), 3000).show();
}
}
在Activity中创建这两种方法：
public void handleGetDirectionsResult(ArrayList<LatLng> directionPoints)
{
Polyline newPolyline;
GoogleMap mMap = ((SupportMapFragment)getSupportFragmentManager().findFragmentById(R.id.map)).getMap();
PolylineOptions rectLine = new PolylineOptions().width(3).color(Color.RED);
for(int i = 0 ; i < directionPoints.size() ; i++)
{
rectLine.add(directionPoints.get(i));
}
newPolyline = mMap.addPolyline(rectLine);
}
public void findDirections(double fromPositionDoubleLat, double fromPositionDoubleLong, double toPositionDoubleLat, double toPositionDoubleLong, String mode)
{
Map<String, String> map = new HashMap<String, String>();
map.put(GetDirectionsAsyncTask.USER_CURRENT_LAT, String.valueOf(fromPositionDoubleLat));
map.put(GetDirectionsAsyncTask.USER_CURRENT_LONG, String.valueOf(fromPositionDoubleLong));
map.put(GetDirectionsAsyncTask.DESTINATION_LAT, String.valueOf(toPositionDoubleLat));
map.put(GetDirectionsAsyncTask.DESTINATION_LONG, String.valueOf(toPositionDoubleLong));
map.put(GetDirectionsAsyncTask.DIRECTIONS_MODE, mode);
GetDirectionsAsyncTask asyncTask = new GetDirectionsAsyncTask(this);
asyncTask.execute(map);
}
最后运行此方法来创建Polyline：
findDirections(AppObj.getInstance().currentUserLocation.getLatitude(),
AppObj.getInstance().currentUserLocation.getLongitude(),
clickMarkerLatLng.latitude, clickMarkerLatLng.longitude, GMapV2Direction.MODE_DRIVING );