【发布时间】：2012-12-16 18:18:59
【问题描述】：
我正在尝试为一个 android 项目查找我当前的位置。加载应用程序时，我的当前位置始终为空。我已经在清单等中设置了权限。当我找到当前位置时，我打算使用坐标来查找到地图上其他位置的距离。我的代码 sn-p 如下。为什么我总是得到一个空值？ 这是我的代码：-
package com.example.location;
import android.content.Context;
import android.location.LocationManager;
import android.os.Bundle;
import android.location.Location;
import com.google.android.maps.MapActivity;
import com.google.android.maps.MapView;
import android.location.LocationListener;
import com.google.android.maps.MapController;
import android.widget.Toast;
import com.google.android.maps.GeoPoint;
public class MainActivity extends MapActivity implements LocationListener {
private MapView mapView;
private LocationManager locManager;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//fetch the map view from the layout
MapView mapView = (MapView) findViewById(R.id.mapview);
//make available zoom controls
mapView.setBuiltInZoomControls(true);
//latitude and longitude of Rome
double lat = 33.6667;
double lon = 73.1667;
//create geo point
GeoPoint point = new GeoPoint((int)(lat * 1E6), (int)(lon *1E6));
//get the MapController object
MapController controller = mapView.getController();
//animate to the desired point
controller.animateTo(point);
//set the map zoom to 13
// zoom 1 is top world view
controller.setZoom(13);
// invalidate the map in order to show changes
**mapView.invalidate();
// Use the location manager through GPS
locManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
locManager.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0,
0, this);
//get the current location (last known location) from the location manager
Location location = locManager
.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);
if (location != null) {
Toast.makeText(
this,
"Current location:\nLatitude: " + location.getLatitude()
+ "\n" + "Longitude: " + location.getLongitude(),
Toast.LENGTH_LONG).show(); }
else {
Toast.makeText(this, "Cannot fetch current location!",
Toast.LENGTH_LONG).show();
}**
//when the current location is found – stop listening for updates (preserves battery)
locManager.removeUpdates(this);
}
@Override
protected boolean isRouteDisplayed() {
return false;
}
@Override
protected void onPause() {
super.onPause();
locManager.removeUpdates(this); //activity pauses => stop listening for updates
}
@Override
public void onLocationChanged(Location location) {
}
@Override
public void onProviderDisabled(String provider) {
}
@Override
public void onProviderEnabled(String provider) {
}
@Override
public void onStatusChanged(String provider, int status, Bundle extras) {
}
}
【问题讨论】：
标签： android google-maps geolocation emulation