Android GB28181接入端实时位置订阅和上报之-如何获取当前经纬度

Posted 2022-09-21 音视频牛哥

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NetWork
            List<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null
            Location 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-ddTHH: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() 
        @Override
        public void onStatusChanged(String provider, int 
        
        @Override
        public void onProviderEnabled(String provider) 
        
        @Override
        public void onProviderDisabled(String provider) 
        
        // 如果位置发生变化，重新显示
        @Override
        public 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：

@Override
    public void ntsOnDevicePositionRequest(String deviceId, int 
        handler_.postDelayed(new Runnable() 
            @Override
            public 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。