在android中快速获取当前位置一次 [英] get the current location fast and once in android

问题描述

我有一个需要设备当前位置(纬度和经度)的 android 应用程序.我在网上尝试了一些教程，特别是堆栈溢出的一些解决方案，但它们对我来说效果不佳.我的要求很简单:首先我需要它快速并且在片段开始时需要一次位置.其次，我需要它尽可能精确，我的意思是如果 GPS 不可用，它应该首先使用 GPS，然后使用网络提供商.

I have an android application that need device current location (latitude and longitude). I've tried some tutorial on the net and specially some solutions from stack overflow, but they doesn't work well for me. My requirement is so simple: First I need it to be fast and need the location once when I the fragment starts. Second I need it to be as precise as possible, I mean it should use GPS first if GPS is not available then use Network provider.

例如，我尝试过 这个解决方案但它在 30 秒后返回 null，但我知道有些事情没问题，因为谷歌地图和其他应用程序运行良好！！！

For example, I've tried this solution but it return null after 30 second, but I know there is some all the things is ok because google map and other application works well !!!

几乎所有答案都建议使用 getLastKnownLocation()，但我想它不是当前的，如果是这样的话我不想要它.

Something that almost all the answers suggest is to use getLastKnownLocation(), but I suppose it's not the current and I don't want it if it is so.

谁能给我一些简单快捷的方法来获得一次位置?！

can anyone suggest me some kind of simple and fast way to get the location just ONCE ?!

推荐答案

这里，你可以用这个...

Here, you can use this...

示例用法:

public void foo(Context context) {
  // when you need location
  // if inside activity context = this;

  SingleShotLocationProvider.requestSingleUpdate(context, 
   new SingleShotLocationProvider.LocationCallback() {
     @Override public void onNewLocationAvailable(GPSCoordinates location) {
       Log.d("Location", "my location is " + location.toString());
     }
   });
}

您可能想要验证 lat/long 是实际值，而不是 0 或其他值.如果我没记错的话，这不应该抛出 NPE，但您可能想要验证这一点.

You might want to verify the lat/long are actual values and not 0 or something. If I remember correctly this shouldn't throw an NPE but you might want to verify that.

public class SingleShotLocationProvider {

  public static interface LocationCallback {
      public void onNewLocationAvailable(GPSCoordinates location);
  }

  // calls back to calling thread, note this is for low grain: if you want higher precision, swap the 
  // contents of the else and if. Also be sure to check gps permission/settings are allowed.
  // call usually takes <10ms
  public static void requestSingleUpdate(final Context context, final LocationCallback callback) {
      final LocationManager locationManager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);
      boolean isNetworkEnabled = locationManager.isProviderEnabled(LocationManager.NETWORK_PROVIDER);
      if (isNetworkEnabled) {
          Criteria criteria = new Criteria();
          criteria.setAccuracy(Criteria.ACCURACY_COARSE);
          locationManager.requestSingleUpdate(criteria, new LocationListener() {
              @Override
              public void onLocationChanged(Location location) {
                  callback.onNewLocationAvailable(new GPSCoordinates(location.getLatitude(), location.getLongitude()));
              }

              @Override public void onStatusChanged(String provider, int status, Bundle extras) { }
              @Override public void onProviderEnabled(String provider) { }
              @Override public void onProviderDisabled(String provider) { }
          }, null);
      } else {
          boolean isGPSEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
          if (isGPSEnabled) {
              Criteria criteria = new Criteria();
              criteria.setAccuracy(Criteria.ACCURACY_FINE);
              locationManager.requestSingleUpdate(criteria, new LocationListener() {
                  @Override
                  public void onLocationChanged(Location location) {
                      callback.onNewLocationAvailable(new GPSCoordinates(location.getLatitude(), location.getLongitude()));
                  }

                  @Override public void onStatusChanged(String provider, int status, Bundle extras) { }
                  @Override public void onProviderEnabled(String provider) { }
                  @Override public void onProviderDisabled(String provider) { }
              }, null);
          }
      }
  }


  // consider returning Location instead of this dummy wrapper class
  public static class GPSCoordinates {
      public float longitude = -1;
      public float latitude = -1;

      public GPSCoordinates(float theLatitude, float theLongitude) {
          longitude = theLongitude;
          latitude = theLatitude;
      }

      public GPSCoordinates(double theLatitude, double theLongitude) {
          longitude = (float) theLongitude;
          latitude = (float) theLatitude;
      }
  }  
}

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