我们在做Android平台GB28181的时候，其中实时位置(MobilePosition)订阅和上报这块，涉及到实时经纬度的获取，特别是执法记录、车载系统的那个等场景，几乎就是标配。

今天主要是分享一段实时获取位置的代码：

/** CameraPublishActivity.java* CameraPublishActivity** Github: https://github.com/daniulive/SmarterStreaming*/private void getLocation(Context context) {try {if ( context == null )return;//1.获取位置管理器if ( mLocationManager == null )mLocationManager = (LocationManager) context.getSystemService(Context.LOCATION_SERVICE);if (mLocationManager == null)return;//2.获取位置提供器，GPS或是NetWorkList<String> providers = mLocationManager.getProviders(true);if ( providers != null ) {if (providers.contains(LocationManager.NETWORK_PROVIDER)){//如果是网络定位mLocationProvider = LocationManager.NETWORK_PROVIDER;}else if (providers.contains(LocationManager.GPS_PROVIDER)){//如果是GPS定位mLocationProvider = LocationManager.GPS_PROVIDER;}else {Toast.makeText(this, "没有可用的位置提供器", Toast.LENGTH_SHORT).show();return;}}if (mLocationProvider == null )return;mLocationManager.removeUpdates(mLocationListener);mLocationManager.requestLocationUpdates(mLocationProvider, 500, 1.0f, mLocationListener);//3.获取上次的位置，一般第一次运行，此值为nullLocation location = mLocationManager.getLastKnownLocation(mLocationProvider);if (location!=null) {updateLocation(location);}}catch (Exception e) {Log.e(TAG, "getLocation exception:" + e.getMessage());e.printStackTrace();}}private void updateLocation(Location location){//long utc_time = location.getTime();//long local_time = utc_time + TimeZone.getDefault().getOffset(utc_time);//Date date = new Date(location.getTime());Date date = new Date(System.currentTimeMillis());SimpleDateFormat dateFormat = new SimpleDateFormat("yyyy-MM-dd'T'HH:mm:ss");String time_str = dateFormat.format(date);// String address = "纬度："+location.getLatitude()+" 经度："+location.getLongitude() + " 时间:" + time_str;//Log.i(TAG, "位置信息: " + address);mLocationTime = time_str;mLatitude   = String.valueOf(location.getLatitude());mLongitude  = String.valueOf(location.getLongitude());}LocationListener mLocationListener = new LocationListener() {@Overridepublic void onStatusChanged(String provider, int {}@Overridepublic void onProviderEnabled(String provider) {}@Overridepublic void onProviderDisabled(String provider) {}// 如果位置发生变化，重新显示@Overridepublic void onLocationChanged(Location location)

国标平台开启位置订阅后，Android平台GB28181接入端根据平台侧发过来的时间间隔要求，周期性的更新实时位置信息，相关流程如下：

 

其中，SUBSCRIBE请求XML描述如下，除了常规信息外，还提供了Interval，供接入端使用。

<?xml versinotallow="1.0" encoding="GB2312"
<Query>
<CmdType>MobilePosition</CmdType>
<SN>55674</SN>
<DeviceID>31011500991320000099</DeviceID>
<Interval>5</Interval>
</Query>

Android国标接入端上报NOTIFY请求示例，请求体XML示例如下：

<?xml versinotallow="1.0" encoding="GB2312"
<Notify>
<CmdType>MobilePosition</CmdType>
<SN>71339</SN>
<TargetID>31011500991320000099</TargetID>
<Time>2022-03-19T12:22:20</Time>
<Longitude>143.507222</Longitude>
<Latitude>33.99011311</Latitude>
</Notify>

当底层有DevicePosition处理诉求时，可参考如下实现：

@Overridepublic void ntsOnDevicePositionRequest(String deviceId, int {handler_.postDelayed(new Runnable() {@Overridepublic void run() {getLocation(context_);Log.v(TAG, "ntsOnDevicePositionRequest, deviceId:" + this.device_id_ + ", Longitude:" + mLongitude+ ", Latitude:" + mLatitude + ", Time:" + mLocationTime);if (mLongitude != null && mLatitude != null) {com.gb.ntsignalling.DevicePosition device_pos = new com.gb.ntsignalling.DevicePosition();device_pos.setTime(mLocationTime);device_pos.setLongitude(mLongitude);device_pos.setLatitude(mLatitude);if (gb28181_agent_ != null ) {gb28181_agent_.updateDevicePosition(device_id_, device_pos);}}}private String device_id_;private int interval_;public Runnable set(String device_id, int {this.device_id_ = device_id;this.interval_ = interval;return this;}}.set(deviceId, interval),0);}

以下是大概的流程，感兴趣的开发者，可以酌情参考。