Flutter中如何使用POST方法发送数据

Question

我有问题，我想使用 POST API 方法发送数据。这里我有几个必须发送的参数，分别是list、string、int、date time等形式。

我已经尝试了 flutter 文档中的示例并且它有效，因为它只发送字符串参数，但在我的情况下，我必须发送大量具有不同数据类型的数据。填null会报错，因为所有的表格都需要从服务端填写

我想知道这里有没有人遇到过类似的情况，或者提供一个如何使用POST API方法发送数据的例子。我非常沮丧和困惑，因为我已经好几天没有完成它了，我试着寻找它，但没有找到与我目前正在经历的情况相关的案例。 请帮忙 谢谢你。

响应更新数据失败

发布API

Future<UserBiodata> sendBiodata(
    String? stAgama,
    // List<Agama>? agama,
    String? stKwn,
    // List<Kwn>? kwn,
    String? tempat,
    String? tglLahir,
    String? nik,
    String? nisn,
    String? npwp,
    String? jalan,
    String? stProv,
    // List<Province>? province,
    String? stKab,
    // List<Province>? kab,
    String? stKec,
    // List<Province>? kec,
    String? desa,
    String? dusun,
    String? rt,
    String? rw,
    String? kodePos,
    dynamic telp,
    String? email,
    String kps,
    String? stTrans,
    // List<Trans>? trans,
    String? stJn,
    // List<Jn>? jn,
    String? ipk,
    // int? smt,
    String? namaAyah,
    String? nikAyah,
    String? tglLahirAyah,
    String? stPendidikanAyah,
    // List<PendidikanAyah>? pendidikanAyah,
    String? pekerjaanAyah,
    String? penghasilanAyah,
    String? namaIbu,
    String? nikIbu,
    String? tglLahirIbu,
    String? stPendidikanIbu,
    // List<PendidikanIbu>? pendidikanIbu,
    String? pekerjaanIbu,
    String? penghasilanIbu,
    String? namaWali,
    String? nikWali,
    String? tglLahirWali,
    String? stPendidikanWali,
    // List<PendidikanWali>? pendidikanWali,
    String? pekerjaanWali,
    String? penghasilanWali,
  ) async {
    String url = Constant.baseURL;
    String token = await UtilSharedPreferences.getToken();
    final response = await http.post(
      Uri.parse(
        '$url/auth/mhs_siakad/biodata/update',
      ),
      headers: <String, String>{
        'Authorization': 'Bearer $token',
        'Content-Type': 'application/json; charset=UTF-8',
      },
      body: jsonEncode(<String, dynamic>{
        "st_agama": stAgama,
        // 'agama': agama,
        'st_kwn': stKwn,
        // 'kwn': kwn,
        "tempat": tempat,
        "tgl_lahir": tglLahir,
        "nik": nik,
        "nisn": nisn,
        "npwp": npwp,
        "jalan": jalan,
        "st_prov": stProv,
        // 'province': province,
        "st_kab": stKab,
        // 'kab': kab,
        "st_kec": stKec,
        // 'kec': kec,
        "desa": desa,
        "dusun": dusun,
        "rt": rt,
        "rw": rw,
        "kode_pos": kodePos,
        "telp": telp,
        "email": email,
        "kps": kps,
        "st_trans": stTrans,
        // 'trans': trans,
        "st_jn": stJn,
        // "jn": jn,
        "ipk": ipk,
        // "smt": smt,
        "nama_ayah": namaAyah,
        "nik_ayah": nikAyah,
        "tgl_lahir_ayah": tglLahirAyah,
        "st_pendidikan_ayah": stPendidikanAyah,
        // "pendidikan_ayah": pendidikanAyah,
        "pekerjaan_ayah": pekerjaanAyah,
        "penghasilan_ayah": penghasilanAyah,
        "nama_ibu": namaIbu,
        "nik_ibu": nikIbu,
        "tgl_lahir_ibu": tglLahirIbu,
        "st_pendidikan_ibu": stPendidikanIbu,
        // "pendidikan_ibu": pendidikanIbu,
        "pekerjaan_ibu": pekerjaanIbu,
        "penghasilan_ibu": penghasilanIbu,
        "nama_wali": namaWali,
        "nik_wali": nikWali,
        "tgl_lahir_wali": tglLahirWali,
        "st_pendidikan_wali": stPendidikanWali,
        // "pendidikan_wali": pendidikanWali,
        "pekerjaan_wali": pekerjaanWali,
        "penghasilan_wali": penghasilanWali,
      }),
    );

    print(response.statusCode);
    print(response.body);

    if (response.statusCode == 201) {
      return UserBiodata.fromJson(jsonDecode(response.body));
    } else {
      throw Exception('Failed update data!');
    }
  }

按钮发送

Center(
          child: ElevatedButton(
            onPressed: () {
              setState(() {
                _futureBiodata = BiodataProvider().sendBiodata(
                  _controllerAgama.text,
                  // _controller2.text as List<Agama>?,
                  _controllerKwn.text,
                  // _controller4.text as List<Kwn>?,
                  _controllerTmtLahir.text,
                  _controllerTglLahir.text,
                  _controllerNik.text,
                  _controllerNisn.text,
                  _controllerNpwp.text,
                  _controllerAlamat.text,
                  _controllerProv.text,
                  // _controller12.text as List<Province>?,
                  _controllerKab.text,
                  // _controller14.text as List<Province>?,
                  _controllerKec.text,
                  // _controller16.text as List<Province>?,
                  _controllerKel.text,
                  _controllerDusun.text,
                  _controllerRt.text,
                  _controllerRw.text,
                  _controllerKdPos.text,
                  _controllerNoHp.text,
                  _controllerEmail.text,
                  _controllerKps.text,
                  _controllerNoKps.text,
                  // _controller26.text as List<Trans>?,
                  _controllerTrans.text,
                  // _controller28.text as List<Jn>?,
                  _controllerJnsTinggal.text,
                  // _controller30.text as int?,
                  _controllerNmAyah.text,
                  _controllerNikAyah.text,
                  _controllerTglLhrAyah.text,
                  _controllerPendidikanAyah.text,
                  // _controller35.text as List<PendidikanAyah>?,
                  _controllerPekerjaanAyah.text,
                  _controllerPenghasilanAyah.text,
                  _controllerNmIbu.text,
                  _controllerNikIbu.text,
                  _controllerTglLhrIbu.text,
                  _controllerPekerjaanIbu.text,
                  // _controller42.text as List<PendidikanIbu>?,
                  _controllerPekerjaanIbu.text,
                  _controllerPenghasilanIbu.text,
                  _controllerNmWali.text,
                  _controllerNikWali.text,
                  _controllerTglLhrWali.text,
                  _controllerPendidikanWali.text,
                  // _controller49.text as List<PendidikanWali>?,
                  _controllerPekerjaanWali.text,
                  _controllerPekerjaanWali.text,
                );
              });
            },
            child: const Text('Update Data'),
          ),
        ),

Answer 1

response.statusCode

可能不是

201

而是

200

。我们需要检查状态码是什么。请使用以下代码代替，如果不起作用，请粘贴结果：

if (response.statusCode ~/100 == 2) {
      return UserBiodata.fromJson(jsonDecode(response.body));
    } else {
      print(response.statusCode)
      print(response.body)
      throw Exception('Failed update data!');
    }

Answer 2

如果要求不允许

null

值，那么在您的

Model

中，如果您使用

non-null

类型，那将是首选。

例子：

//String? stAgama,
String stAgama, // Remove nullable operator
String stKwn,   

....
String <non_nullable_variable>

如果

String

在

null

 中，甚至确保用空字符串填充 

jsonEncode

类型

例子：

 jsonEncode(<String, dynamic>{
        "st_agama": stAgama ?? '', // assigning empty string if null
        'st_kwn': stKwn ?? '',
       
        '<non_nullable_variable>': <null_value> ?? ''

Answer 3

void postData() async {
    final response = await http.post(Uri.parse(uri), body: {
      "title": "Anything",
      "body": "Post body",
      "userid": "1",
    });
    debugPrint(response.statusCode.toString());
  }