检查钉子是否在半径之外或是否在反应本机贴图中

如何解决检查钉子是否在半径之外或是否在反应本机贴图中

我想限制用户将标记/大头针拖动到特定的Km之外，以进行本机反应。我正在使用react-native-maps显示地图，并使用圆圈显示半径。它在iOS上运行良好，只要我将图钉拖动到圆圈之外，它就会提示我，但对于android，提示后会相差200-300米。这是代码，

     <MapView
        provider={PROVIDER_GOOGLE}
        style={{ height: mapHeight }}
        region={region}
        ref={_map}
        zoomEnabled={true}
        minZoomLevel={9}
        onMapReady={() => console.log('ready')}
        onRegionChangeComplete={(region) => _onRegionChangeComplete(region)}
        onDoublePress={_setMapDragging}
        onPanDrag={() => setMapDragging(true)}
      >
        {renderBoundaryCircle()}
      </MapView>

  const renderBoundaryCircle = () => {
    return (
      <Circle
        center={{ latitude: initialAddressLatitude,longitude: 
                  initialAddressLongitude }}
        radius={Platform.OS == 'android' ? 2200 : 2050}
        strokeWidth={2}
        strokeColor={'#1a66ff'}
        lineJoin={'round'}
        fillColor={'rgba(230,238,255,0.5)'}
        ref={_circleRef}
      />
    );
  };

  const _onRegionChangeComplete = (region: RegionObject) => {

    const diffInKm = distanceBwTwoLatLng(
      initialAddressLatitude,initialAddressLongitude,latitude,longitude
    );
    if (diffInKm > 2) {
      alert("beyond 2 km");
    } else {
      if (isMapDragging || Platform.OS == 'ios') {
        setMapDragging(false);
        setRegion(region);
        setLatitude(region.latitude);
        setLongitude(region.longitude);
        console.log(region.latitude,region.longitude);
      }

      //this check is put for zoom,even if I remove this check,nothing changes
      if (!isMapDragging && Platform.OS == 'android') {
        return;
      }
    }
  };

//function to calculate the distance between the initial lat-long and newlat-long
 const distanceBwTwoLatLng = (lat1: number,lon1: number,lat2: number,lon2: number) => {
  const deg2rad = (deg: number) => deg * (Math.PI / 180);
  const R = 6371; // Radius of the earth in km
  const dLat = deg2rad(lat2 - lat1); // deg2rad below
  const dLon = deg2rad(lon2 - lon1);
  const a =
    Math.sin(dLat / 2) * Math.sin(dLat / 2) +
    Math.cos(deg2rad(lat1)) * Math.cos(deg2rad(lat2)) * Math.sin(dLon / 2) * Math.sin(dLon / 2);
  const c = 2 * Math.atan2(Math.sqrt(a),Math.sqrt(1 - a));
  const d = R * c; // Distance in km
  console.log(`Distance in km(s): ${d}`);
  return d;
};

请提出一些解决方案。