位置服务 onProviderEnabled 从未被调用

Question

我有一项可以在我的应用程序中更新位置的服务。当我在禁用 GPS 的情况下启动应用程序，返回 Android 菜单并启用 GPS，最后返回我的应用程序（服务尚未被销毁）时，永远不会调用 onProviderEnabled。有人可以帮忙吗？

更新：如果我重新启动应用程序，则会启用提供程序。仅 onProviderEnabled 未被调用...

在我需要位置的每个活动中，我都会这样做

super.onCreate(savedInstanceState); 

    //....

    // Bind location service
    bindService(new Intent(this, LocationService.class), mConnection, Context.BIND_AUTO_CREATE);

    //....

，并且

@Override
protected void onDestroy() {
    super.onDestroy();       
    // Unbind LocationService
    ItemDetail.this.unbindService(mConnection);
}

服务是

public class LocationService extends Service implements LocationListener {
    LocationManager locationManager; 

    @Override
    public IBinder onBind(Intent intent) {
        return null;
    }

    @Override
    public void onCreate() {        
        locationManager = (LocationManager)getSystemService(Context.LOCATION_SERVICE);

        if (locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)){         

            // Update after minimum 5 minutes and if user has moved at least 100 meters.
            locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 5 * 60 * 1000, 100, this);        

            Location loc = getBestLocation(locationManager);
            if(loc!=null){
                GlobalVars.lat = (Double) (loc.getLatitude());
                GlobalVars.lng = (Double) (loc.getLongitude());
            }
        }
    }

    public void onLocationChanged(Location loc) {        
        GlobalVars.lat = (Double) (loc.getLatitude());
        GlobalVars.lng = (Double) (loc.getLongitude()); 
    }

    public static Location getBestLocation(LocationManager locationManager) {

        Location location_gps = locationManager.getLastKnownLocation(LocationManager.GPS_PROVIDER);
        Location location_network = locationManager.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

        // If both are available, get the most recent
        if(location_gps!=null && location_network !=null) {
            return (location_gps.getTime() > location_network.getTime())?location_gps:location_network;
        }
        else if(location_gps==null && location_network ==null){
            return null;
        }
        else
            return (location_gps==null)?location_network:location_gps;

    }

    public void onProviderEnabled(String s){
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 5 * 60 * 1000, 100, this); 
    }
    public void onProviderDisabled(String s){
        locationManager.removeUpdates(this);
        GlobalVars.lat = null;
        GlobalVars.lng = null;  
    }
    public void onStatusChanged(String s, int i, Bundle b){}

    @Override
    public void onDestroy() {       
        locationManager.removeUpdates(this);
    }
}

Answer 1

在您的 LocationService.onCreate() 方法中，您的代码检查 GPS 提供商是否已禁用。

if (locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER)){...}

但只有在订阅已启用的情况下，您才可以开始订阅。请注意，您的侦听器永远不会向 LocationManager 注册，也不会收到禁用或启用位置提供程序的任何更新。而是将您的 onCreate() 方法更改为始终调用

locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 5 * 60 * 1000, 100, this);