顯示從源地到目的地的路線圖

Question

我想在Google地圖中從源地圖到目的地繪製路線圖。從GP跟蹤源，並且從用戶獲取目的地。我希望路線在這些點之間顯示。想重新繪製地圖，每次的位置被由GPS

Answer 1

這裏是我的地圖活動的數據源更新：

package tvarwebu.projects.map; 

import java.io.IOException; 
import java.io.InputStream; 
import java.net.MalformedURLException; 
import java.net.URL; 
import java.net.URLConnection; 
import java.util.ArrayList; 
import java.util.List; 

import com.google.android.maps.GeoPoint; 
import com.google.android.maps.MapActivity; 
import com.google.android.maps.MapController; 
import com.google.android.maps.MapView; 
import com.google.android.maps.Overlay; 
import com.google.android.maps.OverlayItem; 

import android.graphics.Canvas; 
import android.graphics.Color; 
import android.graphics.Paint; 
import android.graphics.Point; 
import android.graphics.drawable.Drawable; 
import android.location.Location; 
import android.location.LocationManager; 
import android.os.Bundle; 
import android.os.Handler; 

public class MapProjectActivity extends MapActivity { 

GeoPoint myPoint = null; 
GeoPoint nextPoint = null; 
MapView map; 
private Road mRoad; 
int latSpan = -1; 
boolean moving = false; 
long lastTimestamp = 0; 
int pointCount = 0; 
int lat = 0; 
int lng = 0; 
Location currLoc = null; 
OverlayItem currPoint; 
MyItemizedOverlay currItemizedOverlay; 
List<Overlay> mapOverlays; 
LocationManager lm; 

@Override 
protected void onCreate(Bundle savedInstanceState) { 

super.onCreate(savedInstanceState); 
setContentView(R.layout.main); 

map = (MapView) findViewById(R.id.mapView); 
map.setBuiltInZoomControls(true); 
map.setStreetView(true); 
map.setSatellite(false); 

// Your position initialize 
lat = 53324388; 
lng = -6263194; 

myPoint = new GeoPoint(lat, lng); 

Drawable drawable = this.getResources().getDrawable(
R.drawable.flag_green); 

MyItemizedOverlay itemizedoverlay = new MyItemizedOverlay(drawable, 
this); 

OverlayItem overlayitem = new OverlayItem(myPoint, "Start Position", 
"Your start position"); 

itemizedoverlay.addOverlay(overlayitem); 

// Position of next point 
int lat2 = 53348084; 
int lng2 = -6292434; 

nextPoint = new GeoPoint(lat2, lng2); 

OverlayItem overlayitem2 = new OverlayItem(nextPoint, "Position", 
"Position of next point"); 

itemizedoverlay.addOverlay(overlayitem2); 

mapOverlays = map.getOverlays(); 
mapOverlays.add(itemizedoverlay); 

Drawable draw2 = this.getResources().getDrawable(R.drawable.flag_red); 

MyItemizedOverlay over2 = new MyItemizedOverlay(draw2, this); 
over2.addOverlay(overlayitem2); 

mapOverlays.add(over2); 

// zooming to both points 
int maxLatitude = Math.max(lat, lat2); 
int minLatitude = Math.min(lat, lat2); 
int maxLongitude = Math.max(lng, lng2); 
int minLongitude = Math.min(lng, lng2); 

MapController mc = map.getController(); 
mc.zoomToSpan(maxLatitude - minLatitude, maxLongitude - minLongitude); 
mc.animateTo(new GeoPoint((maxLatitude + minLatitude)/2, 
(maxLongitude + minLongitude)/2)); 

map.invalidate(); 

//Drawing path in new Thread 
new Thread() { 

@Override 
public void run() { 
double fromLat = Double.valueOf(myPoint.getLatitudeE6())/1000000.0, 
fromLon = Double.valueOf(myPoint.getLongitudeE6())/1000000.0; 
double toLat = Double.valueOf(nextPoint.getLatitudeE6())/1000000.0, 
toLon = Double.valueOf(nextPoint.getLongitudeE6())/1000000.0; 

String url = RoadProvider 
.getUrl(fromLat, fromLon, toLat, toLon); 
InputStream is = getConnection(url); 
mRoad = RoadProvider.getRoute(is); 
mHandler.sendEmptyMessage(0); 
} 
}.start(); 

} 

Handler mHandler = new Handler() { 
public void handleMessage(android.os.Message msg) { 
MapOverlay mapOverlay = new MapOverlay(mRoad, map); 
List<Overlay> listOfOverlays = map.getOverlays(); 
// listOfOverlays.clear(); 
listOfOverlays.add(mapOverlay); 
map.invalidate(); 
}; 
}; 

private InputStream getConnection(String url) { 
InputStream is = null; 
try { 
URLConnection conn = new URL(url).openConnection(); 
is = conn.getInputStream(); 
} catch (MalformedURLException e) { 
e.printStackTrace(); 
} catch (IOException e) { 
e.printStackTrace(); 
} 
return is; 
} 

@Override 
protected boolean isRouteDisplayed() { 
// TODO Auto-generated method stub 
return false; 
} 
// Map extends overlay for drawing path 
class MapOverlay extends com.google.android.maps.Overlay { 
Road mRoad; 
ArrayList<GeoPoint> mPoints; 

public MapOverlay(Road road, MapView mv) { 
mRoad = road; 
// mRoute is field of route points getting from Google Maps 
if (road.mRoute.length > 0) { 
mPoints = new ArrayList<GeoPoint>(); 
for (int i = 0; i < road.mRoute.length; i++) { 
mPoints.add(new GeoPoint(
(int) (road.mRoute[i][1] * 1000000), 
(int) (road.mRoute[i][0] * 1000000))); 
} 

} 
} 

@Override 
public void draw(Canvas canvas, MapView mv, boolean shadow) { 
drawPath(mv, canvas); 
} 

public void drawPath(MapView mv, Canvas canvas) { 
int x1 = -1, y1 = -1, x2 = -1, y2 = -1; 
Paint paint = new Paint(); 
latSpan = mv.getLatitudeSpan(); 
paint.setColor(Color.parseColor("#998447cc")); 
paint.setStyle(Paint.Style.STROKE); 
paint.setStrokeWidth(6); 
if (mPoints != null) { 
for (int i = 0; i < mPoints.size(); i++) { 
Point point = new Point(); 
mv.getProjection().toPixels(mPoints.get(i), point); 
x2 = point.x; 
y2 = point.y; 
if (i > 0) { 
canvas.drawLine(x1, y1, x2, y2, paint); 
} 
x1 = x2; 
y1 = y2; 
} 
} 
} 
} 
} 

此外，您將需要此文件：

Road.java

package tvarwebu.projects.map; 

public class Road { 
public String mName; 
public String mDescription; 
public int mColor; 
public int mWidth; 
public double[][] mRoute = new double[][] {}; 
public Point[] mPoints = new Point[] {}; 

} 

Point.java

package tvarwebu.projects.map; 

public class Point { 
String mName; 
String mDescription; 
String mIconUrl; 
double mLatitude; 
double mLongitude; 
} 

RoadProvider.java

package tvarwebu.projects.map; 

import java.io.IOException; 
import java.io.InputStream; 
import java.util.Stack; 

import javax.xml.parsers.ParserConfigurationException; 
import javax.xml.parsers.SAXParser; 
import javax.xml.parsers.SAXParserFactory; 

import org.xml.sax.Attributes; 
import org.xml.sax.SAXException; 
import org.xml.sax.helpers.DefaultHandler; 

public class RoadProvider { 

public static Road getRoute(InputStream is) { 
KMLHandler handler = new KMLHandler(); 
try { 
SAXParser parser = SAXParserFactory.newInstance().newSAXParser(); 
parser.parse(is, handler); 
} catch (ParserConfigurationException e) { 
e.printStackTrace(); 
} catch (SAXException e) { 
e.printStackTrace(); 
} catch (IOException e) { 
e.printStackTrace(); 
} 
return handler.mRoad; 
} 

public static String getUrl(double fromLat, double fromLon, double toLat, 
double toLon) {// connect to map web service 
StringBuffer urlString = new StringBuffer(); 
urlString.append("http://maps.google.com/maps?f=d&hl=en"); 
urlString.append("&saddr=");// from 
urlString.append(Double.toString(fromLat)); 
urlString.append(","); 
urlString.append(Double.toString(fromLon)); 
urlString.append("&daddr=");// to 
urlString.append(Double.toString(toLat)); 
urlString.append(","); 
urlString.append(Double.toString(toLon)); 
urlString.append("&ie=UTF8&0&om=0&output=kml"); 

String ggg = urlString.toString(); 
return urlString.toString(); 
} 
} 

class KMLHandler extends DefaultHandler { 
Road mRoad; 
boolean isPlacemark; 
boolean isRoute; 
boolean isItemIcon; 
private Stack mCurrentElement = new Stack(); 
private String mString; 

public KMLHandler() { 
mRoad = new Road(); 
} 

public void startElement(String uri, String localName, String name, 
Attributes attributes) throws SAXException { 
mCurrentElement.push(localName); 
if (localName.equalsIgnoreCase("Placemark")) { 
isPlacemark = true; 
mRoad.mPoints = addPoint(mRoad.mPoints); 
} else if (localName.equalsIgnoreCase("ItemIcon")) { 
if (isPlacemark) 
isItemIcon = true; 
} 
mString = new String(); 
} 

public void characters(char[] ch, int start, int length) 
throws SAXException { 
String chars = new String(ch, start, length).trim(); 
mString = mString.concat(chars); 
} 

public void endElement(String uri, String localName, String name) throws SAXException { 
if (mString.length() > 0) { 
if (localName.equalsIgnoreCase("name")) { 
if (isPlacemark) { 
isRoute = mString.equalsIgnoreCase("Route"); 
if (!isRoute) { 
mRoad.mPoints[mRoad.mPoints.length - 1].mName = mString; 
} 
} else { 
mRoad.mName = mString; 
} 
} else if (localName.equalsIgnoreCase("color") && !isPlacemark) { 
mRoad.mColor = Integer.parseInt(mString, 16); 
} else if (localName.equalsIgnoreCase("width") && !isPlacemark) { 
mRoad.mWidth = Integer.parseInt(mString); 
} else if (localName.equalsIgnoreCase("description")) { 
if (isPlacemark) { 
String description = cleanup(mString); 
if (!isRoute) 
mRoad.mPoints[mRoad.mPoints.length - 1].mDescription = description; 
else 
mRoad.mDescription = description; 
} 
} else if (localName.equalsIgnoreCase("href")) { 
if (isItemIcon) { 
mRoad.mPoints[mRoad.mPoints.length - 1].mIconUrl = mString; 
} 
} else if (localName.equalsIgnoreCase("coordinates")) { 
if (isPlacemark) { 
if (!isRoute) { 
String[] xyParsed = split(mString, ","); 
double lon = Double.parseDouble(xyParsed[0]); 
double lat = Double.parseDouble(xyParsed[1]); 
mRoad.mPoints[mRoad.mPoints.length - 1].mLatitude = lat; 
mRoad.mPoints[mRoad.mPoints.length - 1].mLongitude = lon; 
} else { 
String[] coodrinatesParsed = split(mString, " "); 
int count = 0; 
if(mRoad.mRoute.length < 2) 
mRoad.mRoute = new double[coodrinatesParsed.length][2]; 
else { 
double[][] mRouteTmp = mRoad.mRoute; 
mRoad.mRoute = new double[mRouteTmp.length + coodrinatesParsed.length][2]; 
//for (int i = 0; i < mRouteTmp.length; i++) { 
// mRoad.mRoute[i] = mRouteTmp[i]; 
// mRoad.mRoute[i][i] = mRouteTmp[i][i]; 
//} 
System.arraycopy(mRouteTmp, 0, mRoad.mRoute, 0, mRouteTmp.length); 

count = mRouteTmp.length; 
} 

for (int i = count; i < (mRoad.mRoute.length); i++) { 
String[] xyParsed = split(coodrinatesParsed[i - count], ","); 
for (int j = 0; j < 2 && j < xyParsed.length; j++) 
mRoad.mRoute[i][j] = Double 
.parseDouble(xyParsed[j]); 
} 
} 
} 
} 
} 
mCurrentElement.pop(); 
if (localName.equalsIgnoreCase("Placemark")) { 
isPlacemark = false; 
if (isRoute) 
isRoute = false; 
} else if (localName.equalsIgnoreCase("ItemIcon")) { 
if (isItemIcon) 
isItemIcon = false; 
} 
} 

private String cleanup(String value) { 
String remove = "<br/>"; 
int index = value.indexOf(remove); 
if (index != -1) 
value = value.substring(0, index); 
remove = " "; 
index = value.indexOf(remove); 
int len = remove.length(); 
while (index != -1) { 
value = value.substring(0, index).concat(
value.substring(index + len, value.length())); 
index = value.indexOf(remove); 
} 
return value; 
} 

public Point[] addPoint(Point[] mPoints) { 
Point[] result = new Point[mPoints.length + 1]; 
for (int i = 0; i < mPoints.length; i++) 
result[i] = mPoints[i]; 
result[mPoints.length] = new Point(); 
return result; 
} 

private static String[] split(String strString, String strDelimiter) { 
String[] strArray; 
int iOccurrences = 0; 
int iIndexOfInnerString = 0; 
int iIndexOfDelimiter = 0; 
int iCounter = 0; 
if (strString == null) { 
throw new IllegalArgumentException("Input string cannot be null."); 
} 
if (strDelimiter.length() <= 0 || strDelimiter == null) { 
throw new IllegalArgumentException(
"Delimeter cannot be null or empty."); 
} 
if (strString.startsWith(strDelimiter)) { 
strString = strString.substring(strDelimiter.length()); 
} 
if (!strString.endsWith(strDelimiter)) { 
strString += strDelimiter; 
} 
while ((iIndexOfDelimiter = strString.indexOf(strDelimiter, 
iIndexOfInnerString)) != -1) { 
iOccurrences += 1; 
iIndexOfInnerString = iIndexOfDelimiter + strDelimiter.length(); 
} 

strArray = new String[iOccurrences]; 
iIndexOfInnerString = 0; 
iIndexOfDelimiter = 0; 
while ((iIndexOfDelimiter = strString.indexOf(strDelimiter, 
iIndexOfInnerString)) != -1) { 
strArray[iCounter] = strString.substring(iIndexOfInnerString, 
iIndexOfDelimiter); 
iIndexOfInnerString = iIndexOfDelimiter + strDelimiter.length(); 
iCounter += 1; 
} 

return strArray; 
} 
} 

MyItemizedOverlay.java：

package tvarwebu.projects.map; 

import java.util.ArrayList; 
import android.app.AlertDialog; 
import android.content.Context; 
import android.graphics.drawable.Drawable; 
import com.google.android.maps.ItemizedOverlay; 
import com.google.android.maps.OverlayItem; 

public class MyItemizedOverlay extends ItemizedOverlay<OverlayItem> { 
private ArrayList<OverlayItem> mOverlays = new ArrayList<OverlayItem>(); 
private Context mContext; 

public MyItemizedOverlay(Drawable defaultMarker, Context context) { 
super(boundCenterBottom(defaultMarker)); 
mContext = context; 
} 

public void addOverlay(OverlayItem overlay) { 
mOverlays.add(overlay); 
populate(); 
} 

@Override 
protected OverlayItem createItem(int i) { 
return mOverlays.get(i); 
} 

@Override 
public int size() { 
return mOverlays.size(); 
} 

public void removeLast(){ 
mOverlays.remove(mOverlays.size()-1); 
} 

@Override 
protected boolean onTap(int index) { 
OverlayItem item = mOverlays.get(index); 
AlertDialog.Builder dialog = new AlertDialog.Builder(mContext); 
dialog.setTitle(item.getTitle()); 
dialog.setMessage(item.getSnippet()); 
dialog.show(); 
return true; 
} 
} 

希望這篇文章可以幫助你解決這個問題:)見COMPLE MapView上繪圖路線的源代碼。