如何可靠地获得Glass的最后位置? [英] How to get last location on Glass reliably?

问题描述

LocationManager中的方法getLastLocation()通常返回null，选择最佳提供程序非常棘手.该文档说:

Method getLastLocation() from LocationManager often return null and it's quite tricky to select best provider. The documentation says:

警告:请勿使用LocationManager.getBestProvider()方法或常量GPS_PROVIDER或NETWORK_PROVIDER来侦听位置更新. Glass使用一组动态的提供程序，并且仅侦听单个提供程序可能会导致您的应用程序丢失位置更新.

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.

如何获得最佳的最后位置?

How to get best last location?

推荐答案

由于Glass使用动态的提供程序集，因此您需要从所有提供程序中获取位置并以最佳的精度选择位置:

Because Glass uses dynamic set of providers, you need to get location from all of them and select the location with best accuracy:

 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;
 }

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