Android 位置管理器不起作用
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【中文标题】Android 位置管理器不起作用【英文标题】：Android location manager doesn't work 【发布时间】：2013-01-01 22:45:26 【问题描述】：我正在尝试创建和显示设备当前位置和定义点之间的路线。 我使用此代码：
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;
MapController mc;
Location location;
private MyLocationOverlay myLocationOverlay;
String n;
double longitude;
double latitude;
@Override
public void onCreate(Bundle savedInstanceState)
super.onCreate(savedInstanceState);
SharedData data = SharedData.getInstance();
mapView = new MapView(this,"apyKey");
mapView.setClickable(true);
setContentView(mapView);
_activity = this;
LocationManager lm = (LocationManager)getSystemService(Context.LOCATION_SERVICE);
Location location =lm.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
longitude = location.getLongitude();
latitude = location.getLatitude();
double src_lat = latitude;
double src_long = longitude;
double dest_lat = 38.1267303;
double dest_long = 13.3466097;
String n = String.valueOf(src_long);
Log.d("asd",n);
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.pushpin1);
CustomItemizedOverlay srcitemizedOverlay = new CustomItemizedOverlay(srcdrawable);
//CustomItemizedOverlay srcitemizedOverlay = new CustomItemizedOverlay(getDrawable("com/agarwal/route/pin_green.png"));
OverlayItem srcoverlayitem = new OverlayItem(srcGeoPoint, "Hello!", "This is your Location.");
Drawable destdrawable = this.getResources().getDrawable(R.drawable.pushpin1);
CustomItemizedOverlay destitemizedOverlay = new CustomItemizedOverlay( destdrawable );
// CustomItemizedOverlay destitemizedOverlay = new CustomItemizedOverlay(getDrawable("com/agarwal/route/pin_red.png"));
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;
//era private prima di
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("Caricamento del percorso...");
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");
//end Async
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()
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");
这是针对智能手机 Galaxy Nexus，android 4.2 的应用程序。
我在我的平板电脑 android 4.0.2 上对其进行了测试，它运行良好。
但是当我在智能手机上测试它时，它崩溃了。
我试图用LocationManager.GPS_PROVIDER 更改LocationManager.NETWORK_PROVIDER，但它还是崩溃了。我无法解决这个问题。谁能帮帮我？
【问题讨论】：
LogCat 中的任何错误跟踪？ “不起作用”并没有告诉我们出了什么问题，请发布堆栈跟踪。 为什么你处理这么多不同的catch 案件，而你却以同样的方式处理它们？
我直接在设备上测试。当我用模拟器测试它时，LogCat 说纬度和经度为空
【参考方案1】：
我为同样的问题苦苦挣扎了好几个小时。同一段代码在我的 Android 2.7 设备上运行良好，但不适用于我的 Android 4.1.1。最终，我发现，由于某些原因，如果没有先调用 requestLocationUpdates()，则 getLastKnownLocation() 不起作用。 结果，我的 LocationListener 在我放了这两行之后开始更新：
locationManager.requestLocationUpdates(provider, 1000, 10, locationListener);
Location location = locationManager.getLastKnownLocation(provider);
希望对你有帮助。
【讨论】：
【参考方案2】：您是否在清单文件中授予了适当的权限
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION"/>
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION"/>
查看 Android 开发文档here
【讨论】：
在清单中有文档中指示的所有权限【参考方案3】：你得到一个空指针的机会。
您从 getLastKnownLocation() 获取位置，然后使用此对象而不检查它是否为空。如果没有已知位置，getLastKnownLocation 可以返回 null。
【讨论】：
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