login.dart

// login page dart
  Widget build(BuildContext context) {
    return Scaffold(
      backgroundColor: Colors.white,
      body: SingleChildScrollView(
        child: Container(
          constraints: BoxConstraints(
              maxHeight: MediaQuery.of(context).size.height,
              maxWidth: MediaQuery.of(context).size.width),
          decoration: BoxDecoration(
            color: Colors.white,
          ),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center,
            children: [
              Expanded(
                flex: 2,
                child: Padding(
                  padding: const EdgeInsets.symmetric(
                      vertical: 36.0, horizontal: 24.0),
                  child: Column(
                    mainAxisAlignment: MainAxisAlignment.center,
                    crossAxisAlignment: CrossAxisAlignment.center,
                    children: [
                      Container(
                          decoration: BoxDecoration(
                              color: Colors.blue, shape: BoxShape.rectangle),
                          child: Image.asset('assets/logo.png')),
                      SizedBox(height: 10.0),
                      Text(
                        "Elekronik Pemantauan Indikator Kinerja",
                        style: TextStyle(fontSize: 18),
                      )
                    ],
                  ),
                ),
              ),
              Expanded(
                flex: 5,
                child: Container(
                    width: double.infinity,
                    decoration: BoxDecoration(
                      color: Colors.white,
                    ),
                    child: Padding(
                      padding: EdgeInsets.all(24.0),
                      child: Column(
                        mainAxisAlignment: MainAxisAlignment.center,
                        crossAxisAlignment: CrossAxisAlignment.center,
                        children: [
                          TextField(
                            controller: nikController,
                            keyboardType: TextInputType.number,
                            decoration:
                                InputDecoration(filled: true, hintText: "NIK"),
                          ),
                          SizedBox(
                            height: 20.0,
                          ),
                          TextField(
                            controller: kodePelatihanController,
                            keyboardType: TextInputType.text,
                            decoration: InputDecoration(
                                filled: true, hintText: "Kode Pelatihan"),
                          ),
                          SizedBox(height: 35.0),
                          Container(
                            width: double.infinity,
                            child: ElevatedButton(
                              style: ElevatedButton.styleFrom(
                                  primary: Colorsys.orange),
                              onPressed: () {
                                if (userModel == null ||
                                    userModel!.data == null) {
                                  UserModel.getLoginData(
                                          nik: nikController.text,
                                          kodePelatihan:
                                              kodePelatihanController.text,
                                          apiUrl: apiUrl)
                                      .then((value) {
                                    userModel = value;
                                    MySharedPreferences.instance.setStringValue(
                                        key: 'token',
                                        value: userModel!
                                            .data!.attributes!.token
                                            .toString());
                                    setState(() {});
                                    MySharedPreferences.instance
                                        .getStringValue(key: 'token')
                                        .then((value) {
                                      setState(() {
                                        print('current active token: ' +
                                            value.toString());
                                        Navigator.pushReplacement(
                                            context,
                                            MaterialPageRoute(
                                                builder: (context) => Home()));
                                      });
                                    });
                                  }).catchError((error) {
                                    print('error Found: ' + error.toString());
                                    Navigator.push(
                                        context,
                                        MaterialPageRoute(
                                            builder: (context) =>
                                                NotfoundPage()));
                                  });
                                }
                              },
                              child: Text(
                                "Masuk",
                                style: TextStyle(
                                    color: Colors.white,
                                    fontWeight: FontWeight.bold,
                                    fontSize: 16.0),
                              ),
                            ),
                          ),
                          SizedBox(
                            height: 25.0,
                          ),
                          Image.asset('assets/images/logo_kementan.png'),
                          SizedBox(
                            height: 10.5,
                          ),
                          Text(
                            "PUSLATAN",
                            style: TextStyle(
                                fontWeight: FontWeight.w800, fontSize: 19.0),
                            textAlign: TextAlign.center,
                          ),
                          Text("BPPSDMP - KEMENTAN",
                              style: TextStyle(
                                  fontWeight: FontWeight.w800, fontSize: 19.0),
                              textAlign: TextAlign.center),
                          Text("@2021",
                              style: TextStyle(
                                  fontWeight: FontWeight.w800, fontSize: 19.0),
                              textAlign: TextAlign.center)
                        ],
                      ),
                    )),
              )
            ],
          ),
        ),
      ),
    );