开发一个将在谷歌地图v2中绘制路线的应用程序。问题是它只是显示路线（它没有显示地图）。任何帮助将受到高度赞赏..谢谢
以下是代码：
MainActivity.java
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
public class MainActivity extends Activity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
SharedData data = SharedData.getInstance();
data.setAPIKEY("APIKeyHERe");
data.setSrc_lat(18.5236);
data.setSrc_lng(73.8478);
data.setDest_lat(18.9647);
data.setDest_lng(72.8258);
startActivity(new Intent(MainActivity.this, RoutePath.class));
}
}
import java.util.ArrayList;
import android.graphics.drawable.Drawable;
import com.google.android.maps.ItemizedOverlay;
import com.google.android.maps.OverlayItem;
public class CustomItemizedOverlay extends ItemizedOverlay<OverlayItem> {
private final ArrayList<OverlayItem> mapOverlays = new ArrayList<OverlayItem>();
public CustomItemizedOverlay(Drawable defaultMarker) {
super(boundCenterBottom(defaultMarker));
}
@Override
protected OverlayItem createItem(int i) {
return mapOverlays.get(i);
}
@Override
public int size() {
return mapOverlays.size();
}
public void addOverlay(OverlayItem overlay) {
mapOverlays.add(overlay);
this.populate();
}
}
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Point;
import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapView;
import com.google.android.maps.Overlay;
import com.google.android.maps.Projection;
public class MyOverLay extends Overlay {
private GeoPoint gp1;
private GeoPoint gp2;
private int mode = 0;
private int defaultColor;
Context mContext;
public MyOverLay(Context context, GeoPoint gp1, GeoPoint gp2, int mode)
{
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 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);
}
}
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;
import javax.xml.parsers.DocumentBuilder;
import javax.xml.parsers.DocumentBuilderFactory;
import javax.xml.parsers.ParserConfigurationException;
import org.w3c.dom.Document;
import org.w3c.dom.Element;
import org.w3c.dom.Node;
import org.w3c.dom.NodeList;
import org.xml.sax.SAXException;
import android.app.AlertDialog;
import android.app.ProgressDialog;
import android.content.DialogInterface;
import android.graphics.Color;
import android.graphics.drawable.Drawable;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import com.google.android.maps.GeoPoint;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapView;
import com.google.android.maps.Overlay;
import com.google.android.maps.OverlayItem;
public class RoutePath extends MapActivity {
/** Called when the activity is first created. */
MapView mapView;
private RoutePath _activity;
GeoPoint srcGeoPoint, destGeoPoint;
private static List<Overlay> mOverlays;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
SharedData data = SharedData.getInstance();
mapView = new MapView(this, data.getAPIKEY());
mapView.setClickable(true);
setContentView(mapView);
_activity = this;
double src_lat = data.getSrc_lat();
double src_long = data.getSrc_lng();
double dest_lat = data.getDest_lat();
double dest_long = data.getDest_lng();
if (src_lat == -1 || src_long == -1 || dest_lat == -1
|| dest_long == -1) {
showAlert("Please enter source and destination points");
} else {
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.pushpin);
CustomItemizedOverlay srcitemizedOverlay = new CustomItemizedOverlay(
srcdrawable);
OverlayItem srcoverlayitem = new OverlayItem(srcGeoPoint, "Hello!",
"This is your Location.");
Drawable destdrawable = this.getResources().getDrawable(
R.drawable.pushpin);
CustomItemizedOverlay destitemizedOverlay = new CustomItemizedOverlay(
destdrawable);
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 boolean isRouteDisplayed() {
// TODO Auto-generated method stub
return false;
}
private class connectAsyncTask extends AsyncTask<Void, Void, Void> {
private ProgressDialog progressDialog;
@Override
protected void onPreExecute() {
// TODO Auto-generated method stub
super.onPreExecute();
progressDialog = new ProgressDialog(_activity);
progressDialog.setMessage("Fetching route, Please wait...");
progressDialog.setIndeterminate(true);
progressDialog.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);
Log.d("_geopoints", "::" + _geopoints.size());
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);
progressDialog.dismiss();
} else {
showAlert("Unable to find the route");
}
Overlay ol2 = new MyOverLay(_activity, destGeoPoint,
destGeoPoint, 3);
mOverlays.add(ol2);
progressDialog.dismiss();
mapView.scrollBy(-1, -1);
mapView.scrollBy(1, 1);
} else {
showAlert("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");
Log.d("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;
}
private void showAlert(String message) {
AlertDialog.Builder alert = new AlertDialog.Builder(_activity);
alert.setTitle("Error");
alert.setCancelable(false);
alert.setMessage(message);
alert.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialog, int which) {
// TODO Auto-generated method stub
}
});
alert.show();
}
private Drawable getDrawable(String fileName) {
return Drawable.createFromStream(_activity.getClass().getClassLoader()
.getResourceAsStream(fileName), "pin");
}
}
public class SharedData {
private static SharedData instance = null;
private SharedData() {
// randomizeServers();
}
// data to be shared
private String APIKEY = "";
private double src_lat = -1;
private double src_lng = -1;
private double dest_lat = -1;
private double dest_lng = -1;
/**
* @return the aPIKEY
*/
public String getAPIKEY() {
return APIKEY;
}
/**
* @param aPIKEY
* the aPIKEY to set
*/
public void setAPIKEY(String aPIKEY) {
APIKEY = aPIKEY;
}
/**
* @return the src_lat
*/
public double getSrc_lat() {
return src_lat;
}
/**
* @param src_lat
* the src_lat to set
*/
public void setSrc_lat(double src_lat) {
this.src_lat = src_lat;
}
/**
* @return the src_lng
*/
public double getSrc_lng() {
return src_lng;
}
/**
* @param src_lng
* the src_lng to set
*/
public void setSrc_lng(double src_lng) {
this.src_lng = src_lng;
}
/**
* @return the dest_lat
*/
public double getDest_lat() {
return dest_lat;
}
/**
* @param dest_lat
* the dest_lat to set
*/
public void setDest_lat(double dest_lat) {
this.dest_lat = dest_lat;
}
/**
* @return the dest_lng
*/
public double getDest_lng() {
return dest_lng;
}
/**
* @param dest_lng
* the dest_lng to set
*/
public void setDest_lng(double dest_lng) {
this.dest_lng = dest_lng;
}
public static SharedData getInstance() {
if (null == instance) {
instance = new SharedData();
}
return instance;
}
}