未处理的异常：NoSuchMethodError：在null上调用了方法'updateProfileInfo'

Question

当我按下“材质”按钮时，会引发错误。该材质按钮在对话框中退出，并且当方法调用具有布尔值并且为true时，我想关闭该对话框。

MaterialButton(
          elevation: 5.0,
          shape: RoundedRectangleBorder(
            borderRadius: BorderRadius.circular(10.0),
          ),
          color: Theme.of(context).accentColor,
          child: Padding(
            padding:
                const EdgeInsets.symmetric(vertical: 8.0, horizontal: 16.0),
            child: Text(
              "Save",
              style:
                  TextStyle(color: Colors.white, fontWeight: FontWeight.bold),
            ),
          ),
          onPressed: () async{
            if (formKey.currentState.validate()) {
              bool success =await model.updateProfileInfo(
                  name:nameController.text,
                  email:emailController.text,
                  gender:selectedGender,
                  phone:phoneController.text,
                  address:addressController.text);
              if(success){
                Navigator.pop(context);
              }else{
                Fluttertoast.showToast(msg: "Something went wrong!");
              }
            }
          },
        ),

引发了以下错误

E/flutter (22845): [ERROR:flutter/lib/ui/ui_dart_state.cc(157)] Unhandled Exception: NoSuchMethodError: The method 'updateProfileInfo' was called on null.
E/flutter (22845): Receiver: null
E/flutter (22845): Tried calling: updateProfileInfo(address: "test test", email: "test@test.com", gender: "Male", name: "test test", phone: "9800000000")
E/flutter (22845): #0      Object.noSuchMethod (dart:core-patch/object_patch.dart:53:5)
E/flutter (22845): #1      SheetButton.build.<anonymous closure> (package:ghyampay/screens/profile.dart:484:41)
E/flutter (22845): #2      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:706:14)
E/flutter (22845): #3      _InkResponseState.build.<anonymous closure> (package:flutter/src/material/ink_well.dart:789:36)
E/flutter (22845): #4      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:182:24)
E/flutter (22845): #5      TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:486:11)
E/flutter (22845): #6      BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:264:5)
E/flutter (22845): #7      BaseTapGestureRecognizer.handlePrimaryPointer 

按预期的输出是在按下该按钮时调用updateProfileInfo方法。updateProfileInfo是另一个类，否则会抛出编译时错误。