我正在谷歌地图上开发一个应用程序，想要从当前位置绘制一条线到我尝试了很多的选定点，但是当我选择一个点时，它不会在当前点和我选择的点之间画一条线而是在选定点附近的道路上画线。我的代码如下：
@Override
public void onMapClick(LatLng latlon)
{
this.latlng = null;
this.latlng = latlon;
makePath(this.latlng);
}
private void makePath(LatLng latlon)
{
if(markerPoints.size()>1)
{
markerPoints.clear();
gMap.clear();
isSecondPoint = false;
markerPoints.add(origin);
options.position(origin);
}
if(markerPoints.size()>1)
{
markerPoints.clear();
gMap.clear();
isSecondPoint = false;
markerPoints.add(origin);
options.position(origin);
}
if(!isSecondPoint)
{
markerPoints.add(latlon);
options.position(latlon);
isSecondPoint = true;
editSecond.putFloat("latitude", (float)latlon.latitude);
editSecond.putFloat("longitude", (float)latlon.longitude);
editSecond.commit();
if(!isFirstPoint)
{
origin = markerPoints.get(0);
options.position(origin);
gMap.addMarker(options.icon(BitmapDescriptorFactory.fromResource(R.drawable.marker3)));
}
gMap.addMarker(options.icon(BitmapDescriptorFactory.fromResource(R.drawable.marker3)));
gMap.animateCamera(CameraUpdateFactory.newLatLng(latlon));
}
if(markerPoints.size() >= 2)
{
prevTime = System.currentTimeMillis()/1000L;
dest = markerPoints.get(1);
staticRouteTask = new RouteTask();
staticRouteTask.execute();
}
}
private class RouteTask extends AsyncTask<String, Void, String>
{
String response = "";
private RouteTask() {}
protected String doInBackground(String... urls)
{
document = v2GetRouteDirection.getDocument(origin, dest, MapRouteDirection.MODE_WALKING);
response = "Success";
return response;
}
protected void onPostExecute(String result)
{
//gMap.clear();
if(response.equalsIgnoreCase("Success"))
{
ArrayList<LatLng> directionPoint = v2GetRouteDirection.getDirection(document);
PolylineOptions rectLine = new PolylineOptions().width(10).color(Color.YELLOW);
for (int i = 0; i < directionPoint.size(); i++)
{
rectLine.add(directionPoint.get(i));
}
// Adding route on the map
gMap.addPolyline(rectLine);
MarkerOptions m = new MarkerOptions();
m.position(dest);
m.draggable(true);
gMap.addMarker(m);
m = null;
}
}
}
公共类MapRouteDirection {
public final static String MODE_DRIVING = "driving";
public final static String MODE_WALKING = "walking";
public MapRouteDirection() { }
public Document getDocument(LatLng start, LatLng end, String mode) {
// Origin of route
String str_origin = "origin="+start.latitude+","+start.longitude;
// Destination of route
String str_dest = "destination="+end.latitude+","+end.longitude;
// Sensor enabled
String sensor = "sensor=false";
//Traveling mode
mode = "mode=walking";
//Units setting
String units = "units=metric";
// Building the parameters to the web service
String parameters = str_origin+"&"+str_dest+"&"+sensor+"&"+units+"&"+mode;
// Output format
String output = "json";
// Building the url to the web service
String url = "https://maps.googleapis.com/maps/api/directions/"+output+"?"+parameters;
/* 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=driving";*/
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;
}
答案 0 :(得分：0)
如果您只想在起点和终点之间添加一条线，则只需在折线上添加2个LatLng。
所以而不是
for (int i = 0; i < directionPoint.size(); i++)
{
rectLine.add(directionPoint.get(i));
}
// Adding route on the map
gMap.addPolyline(rectLine);
您可以使用第一个和最后一个LatLng：
rectLine.add(directionPoint.get(0), directionPoint.get(directionPoint.size - 1);
gMap.addPolyline(rectLine);
Polyline的文档给出了这个例子：
Polyline line = map.addPolyline(new PolylineOptions()
.add(new LatLng(51.5, -0.1), new LatLng(40.7, -74.0))
.width(5)
.color(Color.RED));