我已经完成了所有建议的链接和答案，并且已经到了这个阶段，我能够计算距离但不能绘制路线，我只能得到kml文件的最后两点之间的直线是我的代码。
请告诉我如何克服这一点，因为我必须绘制从源头到目的地的完整旅行路线
代码：
public class RoutePath extends MapActivity
{ GeoPoint gp1; GeoPoint gp2;
GeoPoint srcGeoPoint;
GeoPoint destGeoPoint;
double distance;
public class MyOverLay extends com.google.android.maps.Overlay
{
private int mRadius=6;
private int mode=0;
private int defaultColor;
public MyOverLay()
{
}
public MyOverLay(GeoPoint p1,GeoPoint p2,int mode) // GeoPoint is a int. (6E)
{
gp1 = p1;
gp2 = p2;
this.mode = mode;
defaultColor = 999; // no defaultColor
}
public MyOverLay(GeoPoint p1,GeoPoint p2,int mode, int defaultColor)
{
gp1 = p1;
gp2 = p2;
this.mode = mode;
this.defaultColor = defaultColor ;
}
public int getMode()
{
return mode;
}
@Override
public boolean draw(Canvas canvas, MapView mapView, boolean shadow, long when)
{
Projection projection = mapView.getProjection();
if (shadow == false)
{
Paint paint = new Paint();
paint.setAntiAlias(true);
Point point = new Point();
projection.toPixels(gp1, point);
// mode=1：start
if(mode==1)
{
if(defaultColor==999)
paint.setColor(Color.RED);
//Toast.makeText(getBaseContext(), "mode1", Toast.LENGTH_SHORT).show();
else
paint.setColor(defaultColor);
RectF oval=new RectF(point.x - mRadius, point.y - mRadius,point.x + mRadius, point.y + mRadius);
// start point
canvas.drawOval(oval, paint);
}
// mode=2：path
if(mode==2)
{
if(defaultColor==999)
paint.setColor(Color.RED);
//Toast.makeText(getBaseContext(), "mode2", Toast.LENGTH_SHORT).show();
else
paint.setColor(defaultColor);
Point point2 = new Point();
projection.toPixels(gp2, point2);
paint.setStrokeWidth(5);
paint.setAlpha(120);
canvas.drawLine(point.x, point.y, point2.x,point2.y, paint);
}
/* mode=3：end */
else if(mode==3)
{
//the last path
if(defaultColor==999)
{paint.setColor(Color.BLUE);
Toast.makeText(getBaseContext(), "mode3", Toast.LENGTH_SHORT).show();}
else
paint.setColor(defaultColor);
Point point2 = new Point();
projection.toPixels(gp2, point2);
paint.setStrokeWidth(5);
paint.setAlpha(120);
canvas.drawLine(point.x, point.y, point2.x,point2.y, paint);
RectF oval=new RectF(point2.x - mRadius,point2.y - mRadius,point2.x + mRadius,point2.y + mRadius);
paint.setAlpha(255);
canvas.drawOval(oval, paint);
}
}
return super.draw(canvas, mapView, shadow, when);
}
@Override
public boolean onTouchEvent(MotionEvent event, MapView mapView)
{
//---when user lifts his finger---
if (event.getAction() == 1)
{
GeoPoint destGeoPoint = mapView.getProjection().fromPixels(
(int) event.getX(),
(int) event.getY());
Toast.makeText(getBaseContext(),
destGeoPoint.getLatitudeE6() / 1E6 + "," +
destGeoPoint.getLongitudeE6() /1E6 ,
Toast.LENGTH_SHORT).show();
double src_lat = 19.0552; // the testing source
double src_long = 72.8308;
double dest_lat = destGeoPoint.getLatitudeE6() / 1E6; // the testing destination
double dest_long = destGeoPoint.getLongitudeE6() /1E6;
gp1 = new GeoPoint((int) (src_lat * 1E6),(int) (src_long * 1E6));
gp2 = new GeoPoint((int) (dest_lat * 1E6),(int) (dest_long * 1E6));
Geocoder geoCoder = new Geocoder(
getBaseContext(), Locale.getDefault());
try {
List<Address> addresses = geoCoder.getFromLocation(
gp2.getLatitudeE6() / 1E6,
gp2.getLongitudeE6() / 1E6, 1);
String add = "";
if (addresses.size() > 0)
{
for (int i=0; i<addresses.get(0).getMaxAddressLineIndex();
i++)
add += addresses.get(0).getAddressLine(i) + "\n";
}
Toast.makeText(getBaseContext(), add, Toast.LENGTH_SHORT).show();
DrawPath(gp1, gp2 , Color.GREEN, mapView);
}
catch (IOException e) {
e.printStackTrace();
}
return true;
}
else
return false;
}
}
/** Called when the activity is first created. */
MapView mapView;
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
MapView mapView = (MapView) findViewById(R.id.myMapView1);
mapView.setBuiltInZoomControls(true);
double src_lat = 19.0552; // the testing source
double src_long = 72.8308;
gp1 = new GeoPoint(
(int) (src_lat * 1E6),
(int) (src_long * 1E6));
MyOverLay mapOverlay = new MyOverLay();
List<Overlay> listOfOverlays = mapView.getOverlays();
listOfOverlays.clear();
listOfOverlays.add(mapOverlay);
mapView.invalidate();
mapView.setSatellite(true);
mapView.getController().animateTo(gp1);
mapView.getController().setZoom(15);
}
@Override
protected boolean isRouteDisplayed()
{
// TODO Auto-generated method stub
return true;
}
private void DrawPath(GeoPoint src,GeoPoint dest, int color, MapView mMapView01)
{
double distance1=0;
// connect to map web service
StringBuilder urlString = new StringBuilder();
urlString.append("http://maps.google.com/maps?f=d&hl=en");
urlString.append("&saddr=");//from
urlString.append( Double.toString((double)src.getLatitudeE6()/1.0E6 ));
urlString.append(",");
urlString.append( Double.toString((double)src.getLongitudeE6()/1.0E6 ));
urlString.append("&daddr=");//to
urlString.append( Double.toString((double)dest.getLatitudeE6()/1.0E6 ));
urlString.append(",");
urlString.append( Double.toString((double)dest.getLongitudeE6()/1.0E6 ));
urlString.append("&ie=UTF8&0&om=0&output=kml");
Log.d("xxx","URL="+urlString.toString());
// get the kml (XML) doc. And parse it to get the coordinates(direction route).
Document doc = null;
HttpURLConnection urlConnection= null;
URL url = null;
try
{
url = new URL(urlString.toString());
urlConnection=(HttpURLConnection)url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.setDoOutput(true);
urlConnection.setDoInput(true);
// Toast.makeText(getBaseContext(), "Before Connection", Toast.LENGTH_SHORT).show();
urlConnection.connect();
// Toast.makeText(getBaseContext(), "After Connection", Toast.LENGTH_SHORT).show();
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
doc = db.parse(urlConnection.getInputStream());
if(doc.getElementsByTagName("GeometryCollection").getLength()>0)
{
String path = doc.getElementsByTagName("GeometryCollection").item(0).getFirstChild().getFirstChild().getFirstChild().getNodeValue() ;
Log.d("xxx","path="+ path);
String [] pairs = path.split(" ");
String[] lngLat = pairs[0].split(","); // lngLat[0]=longitude lngLat[1]=latitude lngLat[2]=height
// src
GeoPoint startGP = new GeoPoint((int)(Double.parseDouble(lngLat[1])*1E6),(int)(Double.parseDouble(lngLat[0])*1E6));
//mMapView01.getOverlays().add(new MyOverLay(src,src,1));
GeoPoint gp1;
GeoPoint gp2 = startGP;
//Toast.makeText(getBaseContext(), "Before Connection", Toast.LENGTH_SHORT).show();
for(int i=1;i<pairs.length;i++) // the last one would be crash
{
Location locationA = new Location("Point A");
locationA.setLatitude(startGP.getLatitudeE6()/1E6);
locationA.setLongitude(startGP.getLongitudeE6()/1E6);
lngLat = pairs[i].split(",");
gp1 = gp2;
gp2 = new GeoPoint((int)(Double.parseDouble(lngLat[1])*1E6),(int)(Double.parseDouble(lngLat[0])*1E6));
mMapView01.getOverlays().add(new MyOverLay(gp1,gp2,2,color));
mMapView01.invalidate();
Location locationB = new Location("Point B");
locationB.setLatitude(gp2.getLatitudeE6()/1E6);
locationB.setLongitude(gp2.getLongitudeE6()/1E6);
distance1 = + locationA.distanceTo(locationB);
Log.d("xxx","pair:" + pairs[i]);
}
distance = distance1/1000;
if(distance<= 5.00)
{Toast.makeText(getBaseContext(), "DISTANCE = "+ distance, Toast.LENGTH_SHORT).show();}
else
{Toast.makeText(getBaseContext(), "Location out of range",Toast.LENGTH_SHORT).show();}
}
}
catch (MalformedURLException e)
{
e.printStackTrace();
}
catch (IOException e)
{
e.printStackTrace();
}
catch (ParserConfigurationException e)
{
e.printStackTrace();
}
catch (SAXException e)
{
e.printStackTrace();
}
}
答案 0 :(得分：1)
1）不要盲目地复制代码 from some SO question并将其粘贴回代码墙，因为您无法理解它。
2）使用SAX解析器解析KML以获取Lon，Lat和Alt的ArrayList，用空格分隔。
3）使用此代码段。当然这不会编译，你必须弄清楚它的作用。
if (path != null && path.trim().length() > 0)
{
String[] pairs = path.trim().split(" ");
String[] lngLat = pairs[0].split(",");
if (lngLat.length < 3)
lngLat = pairs[1].split(",");
try
{
GeoPoint startGP = new GeoPoint( (int) (Double.parseDouble(lngLat[1]) * 1E6), (int) (Double.parseDouble(lngLat[0]) * 1E6));
new MyOverlay(startGP, startGP, 1);
for (int i = 1; i < pairs.length; i++)
{
lngLat = null;
lngLat = pairs[i].split(",");
gp1 = gp2;
gp2 = new GeoPoint( (int) (Double.parseDouble(lngLat[1]) * 1E6),
(int) (Double.parseDouble(lngLat[0]) * 1E6));
new MyOverlay(gp1, gp2, 2, color);
下次尝试努力理解代码。