我一直忙于寻找如何在 HelloMapView 中的地图上的两个 (GPS) 点之间画一条线，但没有运气。
谁能告诉我怎么做。
假设我使用扩展 MapView 的 HelloMapView。我需要使用叠加层吗？如果是这样，我是否必须覆盖叠加层的 onDraw() 方法并在此处画一条线？我实际上尝试了这些东西，但没有结果。
提前谢谢你！
【问题讨论】：
标签： android google-maps overlay android-mapview draw
是的，您需要使用叠加层。
您需要获取 MapView 的叠加层并将您的新叠加层添加到它上面。
您的类扩展了 Overlay，这是一个透明的画布，您可以像在任何其他画布上一样在其中进行绘制。
您可以使用 mapView.getProjection() 来获取地图视图的投影。
...
在此处找到更多信息：http://blogoscoped.com/archive/2008-12-15-n14.html
【讨论】：
感谢您的帮助。我终于可以在地图上画一条线了。 我就是这样做的：
/** Called when the activity is first created. */
private List<Overlay> mapOverlays;
private Projection projection;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
linearLayout = (LinearLayout) findViewById(R.id.zoomview);
mapView = (MapView) findViewById(R.id.mapview);
mapView.setBuiltInZoomControls(true);
mapOverlays = mapView.getOverlays();
projection = mapView.getProjection();
mapOverlays.add(new MyOverlay());
}
@Override
protected boolean isRouteDisplayed() {
return false;
}
class MyOverlay extends Overlay{
public MyOverlay(){
}
public void draw(Canvas canvas, MapView mapv, boolean shadow){
super.draw(canvas, mapv, shadow);
Paint mPaint = new Paint();
mPaint.setDither(true);
mPaint.setColor(Color.RED);
mPaint.setStyle(Paint.Style.FILL_AND_STROKE);
mPaint.setStrokeJoin(Paint.Join.ROUND);
mPaint.setStrokeCap(Paint.Cap.ROUND);
mPaint.setStrokeWidth(2);
GeoPoint gP1 = new GeoPoint(19240000,-99120000);
GeoPoint gP2 = new GeoPoint(37423157, -122085008);
Point p1 = new Point();
Point p2 = new Point();
Path path = new Path();
Projection projection=mapv.getProjection();
projection.toPixels(gP1, p1);
projection.toPixels(gP2, p2);
path.moveTo(p2.x, p2.y);
path.lineTo(p1.x,p1.y);
canvas.drawPath(path, mPaint);
}
【讨论】：
您可以从传递给 draw() 方法的 MapView 对象中获取投影： mapv.getProjection().toPixels(gP1, p1);
【讨论】：
// This Activity will draw a line between two selected points on Map
public class MainActivity extends MapActivity {
MapView myMapView = null;
MapController myMC = null;
GeoPoint geoPoint = null;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
myMapView = (MapView) findViewById(R.id.mapview);
geoPoint = null;
myMapView.setSatellite(false);
String pairs[] = getDirectionData("ahmedabad", "vadodara");
String[] lngLat = pairs[0].split(",");
// STARTING POINT
GeoPoint startGP = new GeoPoint(
(int) (Double.parseDouble(lngLat[1]) * 1E6), (int) (Double
.parseDouble(lngLat[0]) * 1E6));
myMC = myMapView.getController();
geoPoint = startGP;
myMC.setCenter(geoPoint);
myMC.setZoom(15);
myMapView.getOverlays().add(new DirectionPathOverlay(startGP, startGP));
// NAVIGATE THE PATH
GeoPoint gp1;
GeoPoint gp2 = startGP;
for (int i = 1; i < pairs.length; i++) {
lngLat = pairs[i].split(",");
gp1 = gp2;
// watch out! For GeoPoint, first:latitude, second:longitude
gp2 = new GeoPoint((int) (Double.parseDouble(lngLat[1]) * 1E6),
(int) (Double.parseDouble(lngLat[0]) * 1E6));
myMapView.getOverlays().add(new DirectionPathOverlay(gp1, gp2));
Log.d("xxx", "pair:" + pairs[i]);
}
// END POINT
myMapView.getOverlays().add(new DirectionPathOverlay(gp2, gp2));
myMapView.getController().animateTo(startGP);
myMapView.setBuiltInZoomControls(true);
myMapView.displayZoomControls(true);
}
@Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
private String[] getDirectionData(String srcPlace, String destPlace) {
String urlString = "http://maps.google.com/maps?f=d&hl=en&saddr="
+ srcPlace + "&daddr=" + destPlace
+ "&ie=UTF8&0&om=0&output=kml";
Log.d("URL", urlString);
Document doc = null;
HttpURLConnection urlConnection = null;
URL url = null;
String pathConent = "";
try {
url = new URL(urlString.toString());
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.setDoOutput(true);
urlConnection.setDoInput(true);
urlConnection.connect();
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
doc = db.parse(urlConnection.getInputStream());
} catch (Exception e) {
}
NodeList nl = doc.getElementsByTagName("LineString");
for (int s = 0; s < nl.getLength(); s++) {
Node rootNode = nl.item(s);
NodeList configItems = rootNode.getChildNodes();
for (int x = 0; x < configItems.getLength(); x++) {
Node lineStringNode = configItems.item(x);
NodeList path = lineStringNode.getChildNodes();
pathConent = path.item(0).getNodeValue();
}
}
String[] tempContent = pathConent.split(" ");
return tempContent;
}
}
//*****************************************************************************
DirectionPathOverlay
public class DirectionPathOverlay extends Overlay {
private GeoPoint gp1;
private GeoPoint gp2;
public DirectionPathOverlay(GeoPoint gp1, GeoPoint gp2) {
this.gp1 = gp1;
this.gp2 = gp2;
}
@Override
public boolean draw(Canvas canvas, MapView mapView, boolean shadow,
long when) {
// TODO Auto-generated method stub
Projection projection = mapView.getProjection();
if (shadow == false) {
Paint paint = new Paint();
paint.setAntiAlias(true);
Point point = new Point();
projection.toPixels(gp1, point);
paint.setColor(Color.BLUE);
Point point2 = new Point();
projection.toPixels(gp2, point2);
paint.setStrokeWidth(2);
canvas.drawLine((float) point.x, (float) point.y, (float) point2.x,
(float) point2.y, paint);
}
return super.draw(canvas, mapView, shadow, when);
}
@Override
public void draw(Canvas canvas, MapView mapView, boolean shadow) {
// TODO Auto-generated method stub
super.draw(canvas, mapView, shadow);
}
}
【讨论】：
这是绘制从源纬度和经度到目的地纬度和经度的方向路径的完整源代码。我已经更改了上面的代码以适应纬度和经度，而不是源和目的地。 因此，任何通过他的 gps 访问他的纬度和经度的人都可以从他的 gps 设备获取到目的地坐标的方向。
感谢以上答案，我们可以做出这样的改变并获得路径方向。
public class DrawMapActivity extends MapActivity {
MapView myMapView = null;
MapController myMC = null;
GeoPoint geoPoint = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
myMapView = (MapView) findViewById(R.id.mapview);
geoPoint = null;
myMapView.setSatellite(false);
double fromLat = 12.303534;
double fromLong = 76.64611;
double toLat = 12.9715987;
double toLong = 77.5945627;
String sourceLat = Double.toString(fromLat);
String sourceLong = Double.toString(fromLong);
String destinationLat = Double.toString(toLat);
String destinationLong = Double.toString(toLong);
String pairs[] = getDirectionData(sourceLat,sourceLong, destinationLat, destinationLong );
String[] lngLat = pairs[0].split(",");
// STARTING POINT
GeoPoint startGP = new GeoPoint((int) (Double.parseDouble(lngLat[1]) * 1E6), (int) (Double.parseDouble(lngLat[0]) * 1E6));
myMC = myMapView.getController();
geoPoint = startGP;
myMC.setCenter(geoPoint);
myMC.setZoom(10);
myMapView.getOverlays().add(new DirectionPathOverlay(startGP, startGP));
// NAVIGATE THE PATH
GeoPoint gp1;
GeoPoint gp2 = startGP;
for (int i = 1; i < pairs.length; i++) {
lngLat = pairs[i].split(",");
gp1 = gp2;
// watch out! For GeoPoint, first:latitude, second:longitude
gp2 = new GeoPoint((int) (Double.parseDouble(lngLat[1]) * 1E6),(int) (Double.parseDouble(lngLat[0]) * 1E6));
myMapView.getOverlays().add(new DirectionPathOverlay(gp1, gp2));
Log.d("xxx", "pair:" + pairs[i]);
}
// END POINT
myMapView.getOverlays().add(new DirectionPathOverlay(gp2, gp2));
myMapView.getController().animateTo(startGP);
myMapView.setBuiltInZoomControls(true);
myMapView.displayZoomControls(true);
}
@Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
private String[] getDirectionData(String sourceLat, String sourceLong, String destinationLat, String destinationLong) {
String urlString = "http://maps.google.com/maps?f=d&hl=en&" +"saddr="+sourceLat+","+sourceLong+"&daddr="+destinationLat+","+destinationLong + "&ie=UTF8&0&om=0&output=kml";
Log.d("URL", urlString);
Document doc = null;
HttpURLConnection urlConnection = null;
URL url = null;
String pathConent = "";
try {
url = new URL(urlString.toString());
urlConnection = (HttpURLConnection) url.openConnection();
urlConnection.setRequestMethod("GET");
urlConnection.setDoOutput(true);
urlConnection.setDoInput(true);
urlConnection.connect();
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
doc = db.parse(urlConnection.getInputStream());
} catch (Exception e) {
}
NodeList nl = doc.getElementsByTagName("LineString");
for (int s = 0; s < nl.getLength(); s++) {
Node rootNode = nl.item(s);
NodeList configItems = rootNode.getChildNodes();
for (int x = 0; x < configItems.getLength(); x++) {
Node lineStringNode = configItems.item(x);
NodeList path = lineStringNode.getChildNodes();
pathConent = path.item(0).getNodeValue();
}
}
String[] tempContent = pathConent.split(" ");
return tempContent;
}
}
//*****************************************************************************
class DirectionPathOverlay extends Overlay {
private GeoPoint gp1;
private GeoPoint gp2;
public DirectionPathOverlay(GeoPoint gp1, GeoPoint gp2) {
this.gp1 = gp1;
this.gp2 = gp2;
}
@Override
public boolean draw(Canvas canvas, MapView mapView, boolean shadow,
long when) {
// TODO Auto-generated method stub
Projection projection = mapView.getProjection();
if (shadow == false) {
Paint paint = new Paint();
paint.setAntiAlias(true);
Point point = new Point();
projection.toPixels(gp1, point);
paint.setColor(Color.BLUE);
Point point2 = new Point();
projection.toPixels(gp2, point2);
paint.setStrokeWidth(2);
canvas.drawLine((float) point.x, (float) point.y, (float) point2.x,(float) point2.y, paint);
}
return super.draw(canvas, mapView, shadow, when);
}
@Override
public void draw(Canvas canvas, MapView mapView, boolean shadow) {
// TODO Auto-generated method stub
super.draw(canvas, mapView, shadow);
}
}
希望它对其他 Stack Overflow 用户有所帮助
【讨论】：
这也可以通过使用意图来完成：
final Intent intent = new Intent(Intent.ACTION_VIEW,
Uri.parse(
"http://maps.google.com/maps?" +
"saddr="+YOUR_START_LONGITUDE+","+YOUR_START_LATITUDE+"&daddr="YOUR_END_LONGITUDE+","+YOUR_END_LATITUDE));
intent.setClassName(
"com.google.android.apps.maps",
"com.google.android.maps.MapsActivity");
startActivity(intent);
【讨论】：
只是我会在mapview 中找到带有一些矩形的绘图，只是我们想随心所欲地更改油漆p>
EmptyOverlay.java
public class EmptyOverlay extends Overlay {
private float x1,y1;
private MapExampleActivity mv = null;
private Overlay overlay = null;
public EmptyOverlay(MapExampleActivity mapV){
mv = mapV;
}
@Override
public boolean draw(Canvas canvas, MapView mapView, boolean shadow,
long when) {
// TODO Auto-generated method stub
return super.draw(canvas, mapView, shadow, when);
}
@Override
public boolean onTouchEvent(MotionEvent e, MapView mapView) {
if(mv.isEditMode()){
if(e.getAction() == MotionEvent.ACTION_DOWN){
//when user presses the map add a new overlay to the map
//move events will be catched by newly created overlay
x1 = y1 = 0;
x1 = e.getX();
y1 = e.getY();
overlay = new MapOverlay(mv, x1, y1);
mapView.getOverlays().add(overlay);
}
if(e.getAction() == MotionEvent.ACTION_MOVE){
}
//---when user lifts his finger---
if (e.getAction() == MotionEvent.ACTION_UP) {
}
return true;
}
return false;
}
}
MapExampleActivity.java
public class MapExampleActivity extends MapActivity {
private MapView mapView;
private boolean isEditMode = false;
private Button toogle;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
toogle = (Button)findViewById(R.id.toogleMap);
toogle.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
toogleEditMode();
}
});
mapView = (MapView)findViewById(R.id.mapview);
mapView.setBuiltInZoomControls(true); //display zoom controls
//add one empty overlay acting as a overlay loader. This will catch press events and will add the actual overlays
mapView.getOverlays().add(new EmptyOverlay(this));
mapView.postInvalidate();
}
//toogle edit mode for drawing or navigating the map
private void toogleEditMode(){
isEditMode = !isEditMode;
}
@Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
@Override
protected boolean isLocationDisplayed() {
return false;
}
public boolean isEditMode(){
return this.isEditMode;
}
public MapView getMapView(){
return this.mapView;
}
}
MapOverlay.java
public class MapOverlay extends Overlay {
private float x1,y1,x2,y2;
private GeoPoint p1=null,p2=null;
private MapExampleActivity mv = null;
private Paint paint = new Paint();
private boolean isUp = false;
//constructor receiving the initial point
public MapOverlay(MapExampleActivity mapV,float x,float y){
paint.setStrokeWidth(2.0f);
x1 = x;
y1 = y;
mv = mapV;
p1 = mapV.getMapView().getProjection().fromPixels((int)x1,(int)y1);
}
//override draw method to add our custom drawings
@Override
public boolean draw(Canvas canvas, MapView mapView, boolean shadow,
long when) {
if(p1 != null && p2 != null){
//get the 2 geopoints defining the area and transform them to pixels
//this way if we move or zoom the map rectangle will follow accordingly
Point screenPts1 = new Point();
mapView.getProjection().toPixels(p1, screenPts1);
Point screenPts2 = new Point();
mapView.getProjection().toPixels(p2, screenPts2);
//draw inner rectangle
paint.setColor(0x4435EF56);
paint.setStyle(Style.FILL);
canvas.drawRect(screenPts1.x, screenPts1.y, screenPts2.x, screenPts2.y, paint);
//draw outline rectangle
paint.setColor(0x88158923);
paint.setStyle(Style.STROKE);
canvas.drawRect(screenPts1.x, screenPts1.y, screenPts2.x, screenPts2.y, paint);
}
return true;
}
@Override
public boolean onTouchEvent(MotionEvent e, MapView mapView) {
if(mv.isEditMode() && !isUp){
if(e.getAction() == MotionEvent.ACTION_DOWN){
x1 = y1 = 0;
x1 = e.getX();
y1 = e.getY();
p1 = mapView.getProjection().fromPixels((int)x1,(int)y1);
}
//here we constantly change geopoint p2 as we move out finger
if(e.getAction() == MotionEvent.ACTION_MOVE){
x2 = e.getX();
y2 = e.getY();
p2 = mapView.getProjection().fromPixels((int)x2,(int)y2);
}
//---when user lifts his finger---
if (e.getAction() == MotionEvent.ACTION_UP) {
isUp = true;
}
return true;
}
return false;
}
}
看到这个http://n3vrax.wordpress.com/2011/08/13/drawing-overlays-on-android-map-view/
【讨论】：
Try this one:
Add itemizedOverlay class:
public class AndroidGoogleMapsActivity extends MapActivity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// Displaying Zooming controls
MapView mapView = (MapView) findViewById(R.id.mapview);
mapView.setBuiltInZoomControls(true);
MapController mc = mapView.getController();
double lat = Double.parseDouble("48.85827758964043");
double lon = Double.parseDouble("2.294543981552124");
GeoPoint geoPoint = new GeoPoint((int)(lat * 1E6), (int)(lon * 1E6));
mc.animateTo(geoPoint);
mc.setZoom(15);
mapView.invalidate();
/**
* Placing Marker
* */
List<Overlay> mapOverlays = mapView.getOverlays();
Drawable drawable = this.getResources().getDrawable(R.drawable.mark_red);
AddItemizedOverlay itemizedOverlay =
new AddItemizedOverlay(drawable, this);
OverlayItem overlayitem = new OverlayItem(geoPoint, "Hello", "Sample Overlay item");
itemizedOverlay.addOverlay(overlayitem);
mapOverlays.add(itemizedOverlay);
}
@Override
protected boolean isRouteDisplayed() {
return false;
}
}
【讨论】：
使用 Google Maps Android API v2 真的很容易
只需复制Developer documentation中的示例
（当然你必须先初始化你的地图）
GoogleMap map;
// ... get a map.
// Add a thin red line from London to New York.
Polyline line = map.addPolyline(new PolylineOptions()
.add(new LatLng(51.5, -0.1), new LatLng(40.7, -74.0))
.width(5)
.color(Color.RED));
【讨论】：
public class MainActivity extends FragmentActivity {
List<Overlay> mapOverlays;
GeoPoint point1, point2;
LocationManager locManager;
Drawable drawable;
Document document;
GMapV2GetRouteDirection v2GetRouteDirection;
LatLng fromPosition;
LatLng toPosition;
GoogleMap mGoogleMap;
MarkerOptions markerOptions;
Location location ;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
v2GetRouteDirection = new GMapV2GetRouteDirection();
SupportMapFragment supportMapFragment = (SupportMapFragment) getSupportFragmentManager()
.findFragmentById(R.id.map);
mGoogleMap = supportMapFragment.getMap();
// Enabling MyLocation in Google Map
mGoogleMap.setMyLocationEnabled(true);
mGoogleMap.getUiSettings().setZoomControlsEnabled(true);
mGoogleMap.getUiSettings().setCompassEnabled(true);
mGoogleMap.getUiSettings().setMyLocationButtonEnabled(true);
mGoogleMap.getUiSettings().setAllGesturesEnabled(true);
mGoogleMap.setTrafficEnabled(true);
mGoogleMap.animateCamera(CameraUpdateFactory.zoomTo(12));
markerOptions = new MarkerOptions();
fromPosition = new LatLng(11.663837, 78.147297);
toPosition = new LatLng(11.723512, 78.466287);
GetRouteTask getRoute = new GetRouteTask();
getRoute.execute();
}
/**
*
* @author VIJAYAKUMAR M
* This class Get Route on the map
*
*/
private class GetRouteTask extends AsyncTask<String, Void, String> {
private ProgressDialog Dialog;
String response = "";
@Override
protected void onPreExecute() {
Dialog = new ProgressDialog(MainActivity.this);
Dialog.setMessage("Loading route...");
Dialog.show();
}
@Override
protected String doInBackground(String... urls) {
//Get All Route values
document = v2GetRouteDirection.getDocument(fromPosition, toPosition, GMapV2GetRouteDirection.MODE_DRIVING);
response = "Success";
return response;
}
@Override
protected void onPostExecute(String result) {
mGoogleMap.clear();
if(response.equalsIgnoreCase("Success")){
ArrayList<LatLng> directionPoint = v2GetRouteDirection.getDirection(document);
PolylineOptions rectLine = new PolylineOptions().width(10).color(
Color.RED);
for (int i = 0; i < directionPoint.size(); i++) {
rectLine.add(directionPoint.get(i));
}
// Adding route on the map
mGoogleMap.addPolyline(rectLine);
markerOptions.position(toPosition);
markerOptions.draggable(true);
mGoogleMap.addMarker(markerOptions);
}
Dialog.dismiss();
}
}
@Override
protected void onStop() {
super.onStop();
finish();
}
}
路由助手类
public class GMapV2GetRouteDirection {
public final static String MODE_DRIVING = "driving";
public final static String MODE_WALKING = "walking";
public GMapV2GetRouteDirection() { }
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=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;
}
}
【讨论】：
对于那些真的只是想画一条简单线的人 - 确实还有短版。
GoogleMap map;
// ... get a map.
// Add a thin red line from London to New York.
Polyline line = map.addPolyline(new PolylineOptions()
.add(new LatLng(51.5, -0.1), new LatLng(40.7, -74.0))
.width(5)
.color(Color.RED));
【讨论】：
这对我有用。使用此处提到的方法，我能够在 Google Maps V2 上绘制折线。每当用户位置发生变化时，我都会画一条新线，因此折线看起来像用户在地图上所遵循的路径。
源代码在。 Github: prasang7/eTaxi-Meter
如果您对距离计算和用户界面不感兴趣，请忽略本项目的其他模块。
【讨论】：
只需从这个 url 获取路由并执行下一步...
原点--->起点经纬度
目的地--->终点经纬度
在这里，我将起点设为德里的经纬度，将目的地设为昌迪加尔的纬度经度
https://maps.googleapis.com/maps/api/directions/json?origin=28.704060,77.102493&destination=30.733315,76.779419&sensor=false&key="输入您的地图 API 密钥"
【讨论】：