升级的Flutter后出现Flutter标签栏错误，“ getter'key'被调用为null”

Question

以下NoSuchMethodError被抛出MediaQuery（MediaQueryData（size：Size（360.0，640.0），devicePixelRatio：3.0，textScaleFactor：1.0，platformBrightness：Brightness.light，padding：EdgeInsets.zero，viewPadding：EdgeInsets.zero，viewInsets：EdgeInsets.zero，物理深度：1.7976931348623157157e + 308，alwaysUse24HourFormat：false，可访问Navigation：false，disableAnimations：false，invertColors：false，boldText：false））：getter'key'在null上被调用。接收方：空尝试呼叫：键

由用户创建的导致错误的小部件的祖先是：脚手架文件：///home/midhilajm/Downloads/al-qasier-flutter-solving_issue_20/lib/orderDetails/OrderDetails.dart：27：16引发异常时，这是堆栈：

0 Object.noSuchMethod（dart：core-patch / object_patch.dart：51：5）

1个新的KeyedSubtree.wrap（package：flutter / src / widgets / basic.dart：6605：27）

2 KeyedSubtree.ensureUniqueKeysForList（package：flutter / src / widgets / basic.dart：6623：44）

3 _TabBarViewState._updateChildren（package：flutter / src / material / tabs.dart：1237：37）

4 _TabBarViewState.initState（package：flutter / src / material / tabs.dart：1206：5）...

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import'package：alqaiser / cart / MyCart.dart';导入'package：alqaiser / orderHistory / OrderHistoryModule.dart';导入'package：alqaiser / orderHistory / OrderItem.dart';导入'package：alqaiser / toolbar / MyToolBar.dart';导入'package：alqaiser / utlity / Milla.dart';导入“ package：flutter / material.dart”；

class OrderDetails extends StatefulWidget {
  OrderItem order;
  OrderDetails({this.order}) {}
  @override
  _OrderDetailsState createState() => _OrderDetailsState(order: order);
}

class _OrderDetailsState extends State<OrderDetails> {
  OrderItem order;
  _OrderDetailsState({this.order}) {

  }

  @override
  Widget build(BuildContext context) {
    return Scaffold(
      appBar: MyToolBar().getAppBar(context),
      body: DefaultTabController(
        length: 2,
        child: Scaffold(
          appBar: AppBar(
            title: TabBar(
              tabs: [
                Tab(
                  text: "Work followup",
                ),
                Tab(
                  text: "Payment ",
                ),
              ],
            ),
          ),
          body: TabBarView(children: [getWorkStatus(), getPaymentStatus()]),
        ),
      ),
    );
  }

  Widget getPaymentStatus() {
    if (this.order.paymentS != null)
      return ListView.builder(
          itemCount: this.order.paymentS.length,
          itemBuilder: (BuildContext context, int index) {
            return Bubble(message: this.order.paymentS[index]);
          });
  }

  Widget getWorkStatus() {
    if (this.order.statues != null)
      return ListView.builder(
          itemCount: this.order.statues.length,
          itemBuilder: (BuildContext context, int index) {
            return Bubble(message: this.order.statues[index]);
          });
  }
}

class Bubble extends StatelessWidget {
  Color bg =Colors.blueGrey ;
  String message1="",message2="";
  Bubble(
      {this.message,
      this.time = "12",
      this.delivered = false,
      this.isMe = false});

  final String message, time;
  final delivered, isMe;
  List<String> messageSplit = [];
  @override
  Widget build(BuildContext context) {
    messageSplit = message.split(":");
    if(messageSplit.length>=1?messageSplit[0]!=null?true:false:false)
  message1=messageSplit[0];
    if(messageSplit.length>=3?
  messageSplit[2]!=null?true:false:false)
    message2=messageSplit[2];
    if(messageSplit.length>=2?
    messageSplit[1]!=null?true:false:false)
    bg=isMe ? Colors.white :HexColor(messageSplit[1]);
    final align = isMe ? CrossAxisAlignment.start : CrossAxisAlignment.end;
    final icon = delivered ? Icons.done_all : Icons.done;
    final radius = isMe
        ? BorderRadius.only(
            topRight: Radius.circular(5.0),
            bottomLeft: Radius.circular(10.0),
            bottomRight: Radius.circular(5.0),
          )
        : BorderRadius.only(
            topLeft: Radius.circular(5.0),
            bottomLeft: Radius.circular(5.0),
            bottomRight: Radius.circular(10.0),
          );
    return Column(
      crossAxisAlignment: align,
      children: <Widget>[
        Container(
          margin: const EdgeInsets.all(3.0),
          padding: const EdgeInsets.all(8.0),
          decoration: BoxDecoration(
            boxShadow: [
              BoxShadow(
                  blurRadius: .5,
                  spreadRadius: 1.0,
                  color: Colors.black.withOpacity(.12))
            ],
            color: bg,
            borderRadius: radius,
          ),
          child:Column(
            children: <Widget>[
              Container(

              child:    Text(message1,textAlign: TextAlign.right,style: TextStyle(color: Colors.white),),
          )
          ,
              Text(message2,textAlign: TextAlign.right,
                  style: TextStyle(
                    color: Colors.white70,
                    fontSize: 10.0,
                  )),
            ],
          ),
        )
      ],
    );
  }
}

Answer 1

您应该处理所有条件，例如：

Widget getPaymentStatus() {
 if (this.order.paymentS != null){
   return ListView.builder(
      itemCount: this.order.paymentS.length,
      itemBuilder: (BuildContext context, int index) {
        return Bubble(message: this.order.paymentS[index]);
      });
 }
 else{
  return Container()
 }
}