显示谷歌地图中的路线Android

Question

我有一个Android的谷歌地图问题。
我成功在android上显示地图。但是当我想要显示路线方向时会出现错误。 奇怪的想法是。我的代码在一周前运行良好。但是当我今天运行它时，会出现错误。所以我试图找到新的代码，但它失败了。这是我的代码。 这是我的道路等级

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[] {};} 

这是我的观点类

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

这是我mapoverlay类

public 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; 
     } 
}} 

这是我roadprovider类

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 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 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 = "&#160;"; 
      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; 
    }} 

这是主要活动

public class GoogleMap233Activity 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; 
     double toLat = 50.45, toLon = 30.523333; 
     String url = RoadProvider 
      .getUrl(fromLat, fromLon, toLat, toLon); 
     InputStream is = getConnection(url); 

     mRoad = RoadProvider.getRoute(is); 
     Log.i("Road", mRoad.mRoute.length+""); 
     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; 
    } 
    } 

此代码在mPoints.size（）中的drawPath（）方法中的类MapOverlay（）中显示错误。这是因为mPoints为null。基于mapOverlay（）的构造函数，mPoints为null，因为road.mRoute.length == 0。当我检查roadProvider记录说，它在这部分上的错误

SAXParser parser = SAXParserFactory.newInstance().newSAXParser(); 
       parser.parse(is, handler); 

有人可以检查它给我。非常感谢。

Answer 1

我知道了。这个链接对我来说是一个很大的帮助。
Google Maps API Version difference

希望这会帮助你。