如何检查特定的latlng特别是圆半径

Question

我正在开发模块，其中驾驶员等人处于移动状态并定期在时间段上发送他的位置，其在地图上有航点和方向，我想知道驾驶员是否已进入特定航点区域？我发现Proximity-Alert如果用户进入特定区域就会发出警报，但我想了解其他用户，例如司机，那么我怎么知道司机是否接近特定的路点？我的Proximity-Alert代码如下。当司机进入区域或我必须使用别的东西时，我能用它来发出警报吗？

public class ProximityIntentReceiver extends BroadcastReceiver {
       private static final int NOTIFICATION_ID = 1000;

       @SuppressWarnings("deprecation")
       @Override
       public void onReceive(Context context, Intent intent) {
           String key = LocationManager.KEY_PROXIMITY_ENTERING;
           Boolean entering = intent.getBooleanExtra(key, false);
           if (entering) {
                     Log.d(getClass().getSimpleName(), "entering");
              }else {
                     Log.d(getClass().getSimpleName(), "exiting");
              }
              NotificationManager notificationManager = (NotificationManager) context.getSystemService(Context.NOTIFICATION_SERVICE);

              Intent notificationIntent = new Intent(context, ProximityAlertActivity.class);
              PendingIntent pendingIntent = PendingIntent.getActivity(context, 0, notificationIntent, 0);
              Notification notification = createNotification();
              notification.setLatestEventInfo(context, "Proximity Alert!", "You are near your point of interest.", pendingIntent);

              notificationManager.notify(NOTIFICATION_ID, notification);
      }

       private Notification createNotification() {
              Notification notification = new Notification();
              notification.icon = R.drawable.ic_launcher;
              notification.when = System.currentTimeMillis();
              notification.flags |= Notification.FLAG_AUTO_CANCEL;
              notification.flags |= Notification.FLAG_SHOW_LIGHTS;
              notification.defaults |= Notification.DEFAULT_VIBRATE;
              notification.defaults |= Notification.DEFAULT_LIGHTS;
              notification.ledARGB = Color.WHITE;
              notification.ledOnMS = 1500;
              notification.ledOffMS = 1500;
              return notification;
        }
}

ProximityAlertActivity.java

public class ProximityAlertActivity extends Activity {
    private static final long POINT_RADIUS = 100; // in Meters
    private static final long PROX_ALERT_EXPIRATION = -1; // It will never expire
    private static final String PROX_ALERT_INTENT = "com.androidmyway.demo.ProximityAlert";
    private LocationManager locationManager;
    private EditText latitudeEditText;
    private EditText longitudeEditText;
    private Button addAlertButton;

    @Override
    public void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_proxymity);

            locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);

            latitudeEditText = (EditText) findViewById(R.id.point_latitude);
            longitudeEditText = (EditText) findViewById(R.id.point_longitude);
            addAlertButton = (Button) findViewById(R.id.add_alert_button);

            addAlertButton.setOnClickListener(new OnClickListener() {
                  public void onClick(View v) {
                         addProximityAlert();
                  }
            });

    }

    private void addProximityAlert() {
           double latitude = Double.parseDouble(latitudeEditText.getText().toString());
           double longitude = Double.parseDouble(longitudeEditText.getText().toString());
           Intent intent = new Intent(PROX_ALERT_INTENT);
           PendingIntent proximityIntent = PendingIntent.getBroadcast(this, 0, intent, 0);
           locationManager.addProximityAlert(
                  latitude, // the latitude of the central point of the alert region
                  longitude, // the longitude of the central point of the alert region
                  POINT_RADIUS, // the radius of the central point of the alert region, in meters
                  PROX_ALERT_EXPIRATION, // time for this proximity alert, in milliseconds, or -1 to indicate no                           expiration
                  proximityIntent // will be used to generate an Intent to fire when entry to or exit from the alert region is detected
           );

           IntentFilter filter = new IntentFilter(PROX_ALERT_INTENT);
           registerReceiver(new ProximityIntentReceiver(), filter);
           Toast.makeText(getApplicationContext(),"Alert Added",Toast.LENGTH_SHORT).show();
    }
}