Android中的道路路径

Question

我是 android 新手，我正在测试一个在 android 中提供道路路径的应用程序。但是我这里有很多错误（如下所示）。

    public class MapRouteActivity 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;
                }
        }
}

当我午餐这段代码时，我遇到了所有这些错误，如下所示：

07-30 14:03:08.969: W/dalvikvm(6934): Unable to resolve superclass of Lcom/test/MapRouteActivity; (17)
07-30 14:03:08.969: W/dalvikvm(6934): Link of class 'Lcom/test/MapRouteActivity;' failed
07-30 14:03:08.969: W/dalvikvm(6934): threadid=1: thread exiting with uncaught exception (group=0x2aac87c8)
07-30 14:03:08.979: E/AndroidRuntime(6934): FATAL EXCEPTION: main
07-30 14:03:08.979: E/AndroidRuntime(6934): java.lang.RuntimeException: Unable to instantiate activity ComponentInfo{com.test/com.test.MapRouteActivity}: java.lang.ClassNotFoundException: com.test.MapRouteActivity in loader dalvik.system.PathClassLoader[/data/app/com.test-1.apk]
07-30 14:03:08.979: E/AndroidRuntime(6934):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2585)
07-30 14:03:08.979: E/AndroidRuntime(6934):     at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2679)
07-30 14:03:08.979: E/AndroidRuntime(6934):     at android.app.ActivityThread.access$2300(ActivityThread.java:125)
07-30 14:03:08.979: E/AndroidRuntime(6934):     at android.app.ActivityThread$H.handleMessage(ActivityThread.java:2033)
07-30 14:03:08.979: E/AndroidRuntime(6934):     at android.os.Handler.dispatchMessage(Handler.java:99)
07-30 14:03:08.979: E/AndroidRuntime(6934):     at android.os.Looper.loop(Looper.java:123)
07-30 14:03:08.979: E/AndroidRuntime(6934):     at android.app.ActivityThread.main(ActivityThread.java:4627)
07-30 14:03:08.979: E/AndroidRuntime(6934):     at java.lang.reflect.Method.invokeNative(Native Method)
07-30 14:03:08.979: E/AndroidRuntime(6934):     at java.lang.reflect.Method.invoke(Method.java:521)
07-30 14:03:08.979: E/AndroidRuntime(6934):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:868)
07-30 14:03:08.979: E/AndroidRuntime(6934):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:626)
07-30 14:03:08.979: E/AndroidRuntime(6934):     at dalvik.system.NativeStart.main(Native Method)
07-30 14:03:08.979: E/AndroidRuntime(6934): Caused by: java.lang.ClassNotFoundException: com.test.MapRouteActivity in loader dalvik.system.PathClassLoader[/data/app/com.test-1.apk]
07-30 14:03:08.979: E/AndroidRuntime(6934):     at dalvik.system.PathClassLoader.findClass(PathClassLoader.java:243)
07-30 14:03:08.979: E/AndroidRuntime(6934):     at java.lang.ClassLoader.loadClass(ClassLoader.java:573)
07-30 14:03:08.979: E/AndroidRuntime(6934):     at java.lang.ClassLoader.loadClass(ClassLoader.java:532)
07-30 14:03:08.979: E/AndroidRuntime(6934):     at android.app.Instrumentation.newActivity(Instrumentation.java:1021)
07-30 14:03:08.979: E/AndroidRuntime(6934):     at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2577)
07-30 14:03:08.979: E/AndroidRuntime(6934):     ... 11 more

Answer 1

使用下面的代码片段

private List<Overlay> mapOverlays;

private Projection projection;  

@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);

linearLayout = (LinearLayout) findViewById(R.id.zoomview);
mapView = (MapView) findViewById(R.id.mapview);
mapView.setBuiltInZoomControls(true);

mapOverlays = mapView.getOverlays();        
projection = mapView.getProjection();
mapOverlays.add(new MyOverlay());        

}

@Override
protected boolean isRouteDisplayed() {
return false;

}

class MyOverlay extends Overlay{

public MyOverlay(){

}   

public void draw(Canvas canvas, MapView mapv, boolean shadow){
super.draw(canvas, mapv, shadow);

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(2);

GeoPoint gP1 = new GeoPoint(19240000,-99120000);
GeoPoint gP2 = new GeoPoint(37423157, -122085008);

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);
}

Answer 2

使用以下代码绘制路线路径。

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;
        }
    }
}

添加以下类

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 = "&#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;
    }
}

main.xml

<?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"/>