MaterialButton onPress函数不工作

Question

我使用Material作为一个可重用的组件，但是它的操作无论如何都不起作用。这就是我面临的错误

Exception caught by gesture 
The following _CastError was thrown while handling a gesture:
Null check operator used on a null value

When the exception was thrown, this was the stack: 
#0      ComplaintsScreen.build.<anonymous closure>.<anonymous closure> (package:elagak/Modules/drawer_screens/complaints.dart:177:62)
#1      _InkResponseState._handleTap (package:flutter/src/material/ink_well.dart:1005:21)
#2      GestureRecognizer.invokeCallback (package:flutter/src/gestures/recognizer.dart:198:24)
#3      TapGestureRecognizer.handleTapUp (package:flutter/src/gestures/tap.dart:613:11)
#4      BaseTapGestureRecognizer._checkUp (package:flutter/src/gestures/tap.dart:298:5)
#5      BaseTapGestureRecognizer.acceptGesture (package:flutter/src/gestures/tap.dart:269:7)
#6      GestureArenaManager.sweep (package:flutter/src/gestures/arena.dart:157:27)
#7      GestureBinding.handleEvent (package:flutter/src/gestures/binding.dart:449:20)
#8      GestureBinding.dispatchEvent (package:flutter/src/gestures/binding.dart:425:22)
#9      RendererBinding.dispatchEvent (package:flutter/src/rendering/binding.dart:329:11)
#10     GestureBinding._handlePointerEventImmediately (package:flutter/src/gestures/binding.dart:380:7)
#11     GestureBinding.handlePointerEvent (package:flutter/src/gestures/binding.dart:344:5)
#12     GestureBinding._flushPointerEventQueue (package:flutter/src/gestures/binding.dart:302:7)
#13     GestureBinding._handlePointerDataPacket (package:flutter/src/gestures/binding.dart:285:7)
#17     _invoke1 (dart:ui/hooks.dart:170:10)
#18     PlatformDispatcher._dispatchPointerDataPacket (dart:ui/platform_dispatcher.dart:331:7)
#19     _dispatchPointerDataPacket (dart:ui/hooks.dart:94:31)
(elided 3 frames from dart:async)
Handler: "onTap"
Recognizer: TapGestureRecognizer#cfff4
  debugOwner: GestureDetector
  state: ready
  won arena
  finalPosition: Offset(274.1, 357.3)
  finalLocalPosition: Offset(264.1, 34.3)
  button: 1
  sent tap down

这是我的密码

MyButtonClass(
                                title: "ارسال الطلب",
                                color: "#1D71B8",
                                    pressAction: () {
                              cubit
                                  .contactUS(
                                      email: cubit.loginModel!.data.email.toString() ?? emailController.text,
                                      name: cubit.loginModel!.data.name
                                          .toString() ?? nameController.text,
                                      phone: cubit.loginModel!.data.phone
                                          .toString() ?? phoneController.text,
                                      body: bodyController.text,
                                      title: titleController.text,
                                      //context: context
                              )
                                  .then((value) => showDialog(
                                      context: context,
                                      builder: (BuildContext context) {
                                        return Dialog(
                                          shape: RoundedRectangleBorder(
                                              borderRadius:
                                                  BorderRadius.circular(20.0)),
                                          child: SizedBox(
                                            height: 200,
                                            child: Padding(
                                              padding: const EdgeInsets.all(10),
                                              child: Column(
                                                mainAxisAlignment:
                                                    MainAxisAlignment.center,
                                                crossAxisAlignment:
                                                    CrossAxisAlignment.center,
                                                children: [
                                                  myImage(
                                                      "assets/images/splash/للوجو.png"),
                                                  const Text(
                                                      "شكرا لك يسعادنا دائما انك معانا",
                                                      style: TextStyle(
                                                          fontSize: 16,
                                                          fontWeight:
                                                              FontWeight.w600)),
                                                ],
                                              ),
                                            ),
                                          ),
                                        );
                                      }))
                                  .catchError((e) => print(e.toString()));
                            })

MyButtonClass

import 'package:flutter/material.dart';
import 'package:hexcolor/hexcolor.dart';

class MyButtonClass extends StatelessWidget {
  MyButtonClass({
    required this.pressAction,
    required this.color,
    required this.title,
    Key? key}) : super(key: key);
    void Function()? pressAction;
    String color;
    String title;
  @override
  Widget build(BuildContext context) {
    return SizedBox(
      width: double.infinity,
      height: 60,
      child: MaterialButton(
          shape:
          RoundedRectangleBorder(borderRadius: BorderRadius.circular(15.0)),
          onPressed: pressAction,
          color: HexColor(color),
          child: Text(title,
              style: const TextStyle(fontSize: 16, color: Colors.white))),
    );
  }
}

事实上，我在5个以上的类中使用了这个类，并且在所有的类中都在工作，但是在这里它不工作

我的接触器功能

Future contactUS(
      {required String email,
      required String name,
      required String phone,
      required String body,
      required String title,
      }) async {
    emit(HomeRegisterLoadingState());
    await http.post(Uri.parse('${api}contact-us'), body: {
      'email': email,
      'name': name,
      'phone': phone,
      'body': body,
      'title': title
    }, headers: {
      'Accept': 'application/json'
    }).then((value) {
      if (jsonDecode(value.body)['code'] == 201) {
        Fluttertoast.showToast(msg: jsonDecode(value.body)['msg'].toString());
        emit(HomeRegisterSuccessState());
      } else {
        Fluttertoast.showToast(msg: "حاول مرة اخرى ");
        emit(HomeRegisterErrorState());
      }
    }).catchError((e) {
      Fluttertoast.showToast(msg: "يرجي المحاولة في وقت لاحق");
      print(e.toString());
      emit(HomeRegisterErrorState());
    });
  }

有人能告诉我如何解决这个问题吗?问题是什么？

Answer 1

作为您的错误Null check operator used on a null value

在您的代码中，此异常具有用于null值的条件null。

您的代码：cubit.loginModel!.data

在您的情况下，此cubit.loginModel返回null，请在执行其他操作之前使用print调试此值并修复数据或添加if (cubit.loginModel != null)。