我正在尝试在Android MapView上绘制路线，但我发现实际放大路径几乎是不可能的。我有跟随gocde
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(4);
GeoPoint gP1 = null;
if (addresses.size() > 0) {
gP1 = new GeoPoint((int) (addresses.get(0).getLatitude() * 1E6),
(int) (addresses.get(0).getLongitude() * 1E6));
}
GeoPoint gP2 = null;
if (addresses2.size() > 0) {
gP2 = new GeoPoint((int) (addresses2.get(0).getLatitude() * 1E6),
(int) (addresses2.get(0).getLongitude() * 1E6));
}
Point p1 = new Point();
Point p2 = new Point();
Path path = new Path();
projection.toPixels(gP1, p1);
projection.toPixels(gP2, p2);
path.moveTo(p2.x, p2.y);
path.lineTo(p1.x,p1.y);
canvas.drawPath(path, mPaint);
MapController mc = mymapView.getController();
mc.setZoom(5);
mymapView.invalidate();
我尝试在南卡罗来纳州放置两个地点，并使用mc.animateTo（gP1）放大其中一个点;但每次我这样做都会放大到Broken Arrow，OK，而不是gP1的实际坐标。
答案 0 :(得分：0)
使用以下代码通过放大/缩小:::
绘制粗糙路径public class RoutePath extends MapActivity {
/** Called when the activity is first created. */
MapView mapView;
private RoutePath _activity;
private CustomDialog _customDialog;
GeoPoint srcGeoPoint,destGeoPoint;
private static List<Overlay> mOverlays;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
_activity = this;
MapView mapView = (MapView) findViewById(R.id.mapview);
if(Constants.LOG)Log.d("source geo point","route path:::"+Constants.GPSLAT+"::::"+Constants.GPSLNG);
double src_lat = getIntent().getExtras().getDouble("SRCLAT");
double src_long = getIntent().getExtras().getDouble("SRCLNG");
double dest_lat = getIntent().getExtras().getDouble("DESTLAT");
double dest_long = getIntent().getExtras().getDouble("DESTLNG");
srcGeoPoint = new GeoPoint((int) (src_lat * 1E6),(int) (src_long * 1E6));
destGeoPoint = new GeoPoint((int) (dest_lat * 1E6),(int) (dest_long * 1E6));
List<Overlay> mapOverlays = mapView.getOverlays();
Drawable srcdrawable = this.getResources().getDrawable(R.drawable.pin_green);
CustomItemizedOverlay srcitemizedOverlay = new CustomItemizedOverlay(srcdrawable, this);
OverlayItem srcoverlayitem = new OverlayItem(srcGeoPoint, "Hello!", "This is your Location.");
Drawable destdrawable = this.getResources().getDrawable(R.drawable.pin_red);
CustomItemizedOverlay destitemizedOverlay = new CustomItemizedOverlay(destdrawable, this);
OverlayItem destoverlayitem = new OverlayItem(destGeoPoint, "Hello!", "This is dest Location.");
srcitemizedOverlay.addOverlay(srcoverlayitem);
destitemizedOverlay.addOverlay(destoverlayitem);
mapOverlays.add(srcitemizedOverlay);
mapOverlays.add(destitemizedOverlay);
connectAsyncTask _connectAsyncTask = new connectAsyncTask();
_connectAsyncTask.execute();
mapView.setBuiltInZoomControls(true);
mapView.displayZoomControls(true);
mOverlays = mapView.getOverlays();
mapView.getController().animateTo(srcGeoPoint);
mapView.getController().setZoom(12);
}
@Override
protected void onStop() {
super.onStop();
//stop custom dialog
}
@Override
protected boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
private class connectAsyncTask extends AsyncTask<Void, Void, Void>{
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
//customDialog show();
}
@Override
protected Void doInBackground(Void... params) {
// TODO Auto-generated method stub
fetchData();
return null;
}
@Override
protected void onPostExecute(Void result) {
// TODO Auto-generated method stub
super.onPostExecute(result);
if(doc!=null){
Overlay ol = new MyOverLay(_activity,srcGeoPoint,srcGeoPoint,1);
mOverlays.add(ol);
NodeList _nodelist = doc.getElementsByTagName("status");
Node node1 = _nodelist.item(0);
String _status1 = node1.getChildNodes().item(0).getNodeValue();
if(_status1.equalsIgnoreCase("OK")){
NodeList _nodelist_path = doc.getElementsByTagName("overview_polyline");
Node node_path = _nodelist_path.item(0);
Element _status_path = (Element)node_path;
NodeList _nodelist_destination_path = _status_path.getElementsByTagName("points");
Node _nodelist_dest = _nodelist_destination_path.item(0);
String _path = _nodelist_dest.getChildNodes().item(0).getNodeValue();
List<GeoPoint> _geopoints = decodePoly(_path);
GeoPoint gp1;
GeoPoint gp2;
gp2 = _geopoints.get(0);
for(int i=1;i<_geopoints.size();i++) // the last one would be crash
{
gp1 = gp2;
gp2 = _geopoints.get(i);
Overlay ol1 = new MyOverLay(gp1,gp2,2,Color.BLUE);
mOverlays.add(ol1);
}
Overlay ol2 = new MyOverLay(_activity,destGeoPoint,destGeoPoint,3);
mOverlays.add(ol2);
//customDialog dismiss();
}else{
Util.showAlertGoBack(_activity,"Unable to find the route");
}
// String _status = node.getNodeValue();
if(Constants.LOG)Log.d("sdsds","dsds"+_status1);
Overlay ol2 = new MyOverLay(_activity,destGeoPoint,destGeoPoint,3);
mOverlays.add(ol2);
// customDialog dismiss();
}else{
//Util.showAlertGoBack(_activity,"Unable to find the route");
}
}
}
Document doc = null;
private void fetchData()
{
StringBuilder urlString = new StringBuilder();
urlString.append("http://maps.google.com/maps/api/directions/xml?origin=");
urlString.append( Double.toString((double)srcGeoPoint.getLatitudeE6()/1.0E6 ));
urlString.append(",");
urlString.append( Double.toString((double)srcGeoPoint.getLongitudeE6()/1.0E6 ));
urlString.append("&destination=");//to
urlString.append( Double.toString((double)destGeoPoint.getLatitudeE6()/1.0E6 ));
urlString.append(",");
urlString.append( Double.toString((double)destGeoPoint.getLongitudeE6()/1.0E6 ));
urlString.append("&sensor=true&mode=driving");
if(Constants.LOG)Log.d("xxx","URL="+urlString.toString());
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);
urlConnection.connect();
DocumentBuilderFactory dbf = DocumentBuilderFactory.newInstance();
DocumentBuilder db = dbf.newDocumentBuilder();
doc = (Document) db.parse(urlConnection.getInputStream());//Util.XMLfromString(response);
}catch (MalformedURLException e){
e.printStackTrace();
}catch (IOException e){
e.printStackTrace();
}catch (ParserConfigurationException e){
e.printStackTrace();
}
catch (SAXException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
private List<GeoPoint> decodePoly(String encoded) {
List<GeoPoint> poly = new ArrayList<GeoPoint>();
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;
GeoPoint p = new GeoPoint((int) (((double) lat / 1E5) * 1E6),
(int) (((double) lng / 1E5) * 1E6));
poly.add(p);
}
return poly;
}
}
MyOverLay.java
public class MyOverLay extends Overlay
{
private GeoPoint gp1;
private GeoPoint gp2;
//private int mRadius=6;
private int mode=0;
private int defaultColor;
private String text="";
private Bitmap img = null;
Context mContext;
public MyOverLay(Context context,GeoPoint gp1,GeoPoint gp2,int mode) // GeoPoint is a int. (6E)
{
this.gp1 = gp1;
this.gp2 = gp2;
this.mode = mode;
this.mContext = context;
defaultColor = 999; // no defaultColor
}
public MyOverLay(GeoPoint gp1,GeoPoint gp2,int mode, int defaultColor)
{
this.gp1 = gp1;
this.gp2 = gp2;
this.mode = mode;
this.defaultColor = defaultColor;
}
public void setText(String t)
{
this.text = t;
}
public void setBitmap(Bitmap bitmap)
{
this.img = bitmap;
}
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.BLUE);
else
paint.setColor(defaultColor);
// start point
}
// mode=2：path
else if(mode==2)
{
if(defaultColor==999)
paint.setColor(Color.RED);
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.GREEN);
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);
/* end point */
}
}
return super.draw(canvas, mapView, shadow, when);
}
}