Flutter obtener ID

rows.dart

    Container seleccionBlock(double rotacion, double margin, int contador) {
      return Container(
          margin: EdgeInsets.only(top: margin),
          child: Transform.rotate(
            angle: rotacion,
            child: Container(
              width: 110.0,
              height: 196.0,
              // padding: const EdgeInsets.all(4.0),

              decoration: BoxDecoration(
               color: const Color.fromRGBO(210, 107, 107, 1.0),
               border: new Border.all(color: Colors.black54)
               
              ),
              child: new Image(image: new AssetImage('assets/'+ aleatorio(contador)+'.jpg')),
            ),
          ));
    }