我想在路线图中画一条线。为此，我使用了http://csie-tw.blogspot.com/2009/06/android-driving-direction-route-path.html中的代码。但它不起作用。它显示了这种错误（（（（java.lang.RuntimeException：无法启动活动ComponentInfo {...............}：android.os.NetworkOnMainThreadException））））。我的清单文件没问题。出了什么问题？
感谢您的建议。
答案 0 :(得分：1)
使用以下代码。
MainActivity.java
public class MainActivity extends MapActivity {
LinearLayout linearLayout;
MapView mapView;
private Road mRoad;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mapView = (MapView) findViewById(R.id.mapview);
mapView.setBuiltInZoomControls(true);
new Thread() {
@Override
public void run() {
double fromLat = 49.85, fromLon = 24.016667, toLat = 50.45, toLon = 30.523333;
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) {
TextView textView = (TextView) findViewById(R.id.description);
textView.setText(mRoad.mName + " " + mRoad.mDescription);
MapOverlay mapOverlay = new MapOverlay(mRoad, mapView);
List<Overlay> listOfOverlays = mapView.getOverlays();
listOfOverlays.clear();
listOfOverlays.add(mapOverlay);
mapView.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() {
return false;
}
}
class MapOverlay extends com.google.android.maps.Overlay {
Road mRoad;
ArrayList<GeoPoint> mPoints;
public MapOverlay(Road road, MapView mv) {
mRoad = road;
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)));
}
int moveToLat = (mPoints.get(0).getLatitudeE6() + (mPoints.get(
mPoints.size() - 1).getLatitudeE6() - mPoints.get(0)
.getLatitudeE6()) / 2);
int moveToLong = (mPoints.get(0).getLongitudeE6() + (mPoints.get(
mPoints.size() - 1).getLongitudeE6() - mPoints.get(0)
.getLongitudeE6()) / 2);
GeoPoint moveTo = new GeoPoint(moveToLat, moveToLong);
MapController mapController = mv.getController();
mapController.animateTo(moveTo);
mapController.setZoom(7);
}
}
@Override
public boolean draw(Canvas canvas, MapView mv, boolean shadow, long when) {
super.draw(canvas, mv, shadow);
drawPath(mv, canvas);
return true;
}
public void drawPath(MapView mv, Canvas canvas) {
int x1 = -1, y1 = -1, x2 = -1, y2 = -1;
Paint paint = new Paint();
paint.setColor(Color.GREEN);
paint.setStyle(Paint.Style.STROKE);
paint.setStrokeWidth(3);
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;
}
}
}
添加以下课程
Point.java
public class Point {
String mName;
String mDescription;
String mIconUrl;
double mLatitude;
double mLongitude;
}
Road.java
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[] {};
}
RoadProvider.java
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");
return urlString.toString();
}
}
class KMLHandler extends DefaultHandler {
Road mRoad;
boolean isPlacemark;
boolean isRoute;
boolean isItemIcon;
private Stack<String> mCurrentElement = new Stack<String>();
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 lenNew = coodrinatesParsed.length;
int lenOld = mRoad.mRoute.length;
double[][] temp = new double[lenOld + lenNew][2];
for (int i = 0; i < lenOld; i++) {
temp[i] = mRoad.mRoute[i];
}
for (int i = 0; i < lenNew; i++) {
String[] xyParsed = split(coodrinatesParsed[i], ",");
for (int j = 0; j < 2 && j < xyParsed.length; j++)
temp[lenOld + i][j] = Double
.parseDouble(xyParsed[j]);
}
mRoad.mRoute = temp;
}
}
}
}
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[] points) {
Point[] result = new Point[points.length + 1];
for (int i = 0; i < points.length; i++)
result[i] = points[i];
result[points.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;
}
}
main.xml中
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/description"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<com.google.android.maps.MapView
android:id="@+id/mapview"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:apiKey="Your API Key"
android:clickable="true" />
</LinearLayout>
将以下权限添加到您的Android清单文件中。
<uses-permission android:name="android.permission.INTERNET"/>