Question

我正在开发一个Android应用程序，我需要计算车辆行驶的总距离，到目前为止所花费的时间和等待时间，类似于ola app。我该怎么办

Answer 1

地图中的导航服务在maps.google.com类下提供，您获得的响应采用KML格式。

要获取kml文件，我们需要形成包含起始位置和目标位置的网址：

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();
}

接下来，您需要创建一个Object类，它将解析xml（使用SAXParser实现）并填充数据结构：

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

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[] {};
}

此特定示例的完整源代码可在此link中找到。

该类中的主线是调用getURL和getRoute方法。

public static String getUrl(double fromLat, double fromLon,
double toLat, double toLon)

要获得源和布置的路线，您需要调用此方法。

public static Road getRoute(InputStream is)

要在Adroid应用程序中实现这段代码，请查看以下代码：

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; 
double 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;
}
}

希望这会有所帮助!!!

Android位置应用程序

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