Flutter网络图片转base64

用dio get请求网络图片的url，请求的options需要设置一下responseType

Options(responseType: ResponseType.bytes)

方法如下:

static Future<String> netImageToBase64(String imageUrl) async {
    Response response = await NetworkManager().get(
      imageUrl,
      options: Options(responseType: ResponseType.bytes),
    );

    String base64Str = base64Encode(response.data);

    return base64Str;
}