google-glass - 如何可靠地获取 Glass 上的最后一个位置？

Question

方法getLastLocation()来自 LocationManager通常返回 null 并且选择最佳提供者非常棘手。文档说:

Warning: Do not use the LocationManager.getBestProvider() method or the constants GPS_PROVIDER or NETWORK_PROVIDER to listen for location updates. Glass uses a dynamic set of providers and listening only to a single provider may cause your application to miss location updates.

如何获得最佳最后位置？

Answer 1

由于 Glass 使用一组动态提供者，您需要从所有提供者中获取位置并选择最准确的位置:

 public static Location getLastLocation(Context context) {
      LocationManager manager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);
      Criteria criteria = new Criteria();
      criteria.setAccuracy(Criteria.NO_REQUIREMENT);
      List<String> providers = manager.getProviders(criteria, true);
      List<Location> locations = new ArrayList<Location>();
      for (String provider : providers) {
           Location location = manager.getLastKnownLocation(provider);
           if (location != null && location.getAccuracy()!=0.0) {
               locations.add(location);
           }
      }
      Collections.sort(locations, new Comparator<Location>() {
          @Override
          public int compare(Location location, Location location2) {
              return (int) (location.getAccuracy() - location2.getAccuracy());
          }
      });
      if (locations.size() > 0) {
          return locations.get(0);
      }
      return null;
 }