Arcgis 地图：获取当前位置错误，不显示我的当前位置

Question

你好，

我尝试了这个示例代码，这个示例代码是在堆栈溢出的另一个问题中给我这个的人之一。我尝试使用此代码，但是当我运行 applicationn 时，它没有找到我当前的设备，甚至没有显示我的位置的一个点.. 代码没有给我任何红色下划线错误，但我无法找到当前位置我我在。

我错过了什么？有没有人有一个示例工作源代码文件，我可以从中下载以获取我当前的设备位置？

我使用的代码如下，

这是我的 MainActivity.class

public class MainActivity extends Activity {

MapView mMapView;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    mMapView = (MapView) findViewById(R.id.mapview);
     mMapView.addLayer(new ArcGISTiledMapServiceLayer(
         "http://services.arcgisonline.com/ArcGIS/rest/services/World_Topo_Map/MapServer"));
    mMapView = new MapView(this);

    LocationResult locationResult = new LocationResult(){
        @Override
        public void gotLocation(Location loc){

        }
    };  
    MyLocation mylocation = new MyLocation();
    mylocation.getLocation(this, locationResult);

}

这是 MyLocation.java

public class MyLocation {
Timer timer1;
LocationManager lm;
LocationResult locationResult;
boolean gps_enabled=false;
boolean network_enabled=false;

public boolean getLocation(Context context, LocationResult result)
{
    //I use LocationResult callback class to pass location value from MyLocation to user code.
    locationResult=result;
    if(lm==null)
        lm = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);

    //exceptions will be thrown if provider is not permitted.
    try{gps_enabled=lm.isProviderEnabled(LocationManager.GPS_PROVIDER);}catch(Exception ex){}
    try{network_enabled=lm.isProviderEnabled(LocationManager.NETWORK_PROVIDER);}catch(Exception ex){}

    //don't start listeners if no provider is enabled
    if(!gps_enabled && !network_enabled)
        return false;

    if(gps_enabled)
        lm.requestLocationUpdates(LocationManager.GPS_PROVIDER, 0, 0, locationListenerGps);
    if(network_enabled)
        lm.requestLocationUpdates(LocationManager.NETWORK_PROVIDER, 0, 0, locationListenerNetwork);
    timer1=new Timer();
    timer1.schedule(new GetLastLocation(), 20000);
    return true;
}

LocationListener locationListenerGps = new LocationListener() {
    public void onLocationChanged(Location location) {
        timer1.cancel();
        locationResult.gotLocation(location);
        lm.removeUpdates(this);
        lm.removeUpdates(locationListenerNetwork);
    }
    public void onProviderDisabled(String provider) {}
    public void onProviderEnabled(String provider) {}
    public void onStatusChanged(String provider, int status, Bundle extras) {}
};

LocationListener locationListenerNetwork = new LocationListener() {
    public void onLocationChanged(Location location) {
        timer1.cancel();
        locationResult.gotLocation(location);
        lm.removeUpdates(this);
        lm.removeUpdates(locationListenerGps);
    }
    public void onProviderDisabled(String provider) {}
    public void onProviderEnabled(String provider) {}
    public void onStatusChanged(String provider, int status, Bundle extras) {}
};

class GetLastLocation extends TimerTask {
    @Override
    public void run() {
         lm.removeUpdates(locationListenerGps);
         lm.removeUpdates(locationListenerNetwork);

         Location net_loc=null, gps_loc=null;
         if(gps_enabled)
             gps_loc=lm.getLastKnownLocation(LocationManager.GPS_PROVIDER);
         if(network_enabled)
             net_loc=lm.getLastKnownLocation(LocationManager.NETWORK_PROVIDER);

         //if there are both values use the latest one
         if(gps_loc!=null && net_loc!=null){
             if(gps_loc.getTime()>net_loc.getTime())
                 locationResult.gotLocation(gps_loc);
             else
                 locationResult.gotLocation(net_loc);
             return;
         }

         if(gps_loc!=null){
             locationResult.gotLocation(gps_loc);
             return;
         }
         if(net_loc!=null){
             locationResult.gotLocation(net_loc);
             return;
         }
         locationResult.gotLocation(null);
    }
}

public static abstract class LocationResult{
    public abstract void gotLocation(Location location);
}
}

Answer 1

您必须编写代码以在当前为空的 gotLocation 方法中显示一个红点。这就是为什么地图顶部没有显示任何内容的原因。