如何在Flutter中针对Web API发出POST请求

我通过使用以下代码解决了问题

     Future post(String url,var body)async{
        return await http
            .post(Uri.encodeFull(url), body: body, headers: {"Accept":"application/json"})
            .then((http.Response response) {
    //      print(response.body);
          final int statusCode = response.statusCode;
          if (statusCode < 200 || statusCode > 400 || json == null) {
            throw new Exception("Error while fetching data");
          }
          return _decoder.convert(response.body);
        });
      }