使用颤振中的选项卡项进行提供程序调用处理

如何解决使用颤振中的选项卡项进行提供程序调用处理

我使用相同的提供程序和模型来存储状态，以便我的 api 以不同的订单状态进行订购，因为只有订单状态发生变化，我将它们显示在选项卡栏中的单独屏幕中，并调用提供程序来获取每个选项卡开关上的响应，但是我在使用 dispose 方法时遇到错误，并且在频繁切换时整个选项卡视图中的数据也不一致，有人可以提出解决此问题的正确方法吗？

这是我的标签项代码

                        OrderMainScreen(token: _token),OrderStatusScreen(
                          token: _token,orderStatus: "unpaid",),orderStatus: "processing",orderStatus: "delivered",]),

这是我获取订单状态的代码

class OrderStatusScreen extends StatefulWidget {
  final String token;
  final String orderStatus;

  OrderStatusScreen({this.token,this.orderStatus});

  _OrderStatusScreenState createState() => _OrderStatusScreenState();
}

class _OrderStatusScreenState extends State<OrderStatusScreen> {
  void initState() {
    if (mounted) {
      Future.delayed(Duration.zero).then((value) {
        Provider.of<OrderProvider>(context,listen: false)
            .fetchUserOrderStatus(widget.token,status: widget.orderStatus);
      });
      super.initState();
    }
  }

频繁切换标签时出现此错误

W/MediaPlayer-JNI(28753): MediaPlayer finalized without being released
E/flutter (28753): [ERROR:flutter/lib/ui/ui_dart_state.cc(186)] Unhandled Exception: This widget has been unmounted,so the State no longer has a context (and should be considered defunct).
E/flutter (28753): Consider canceling any active work during "dispose" or using the "mounted" getter to determine if the State is still active.
[38;5;244mE/flutter (28753): #0      State.context.<anonymous closure>[39;49m
[38;5;244mE/flutter (28753): #1      State.context[39;49m
[38;5;248mE/flutter (28753): #2      _OrderStatusScreenState.initState.<anonymous closure>[39;49m
[38;5;244mE/flutter (28753): #3      _rootRunUnary (dart:async/zone.dart:1362:47)[39;49m
[38;5;244mE/flutter (28753): #4      _CustomZone.runUnary (dart:async/zone.dart:1265:19)[39;49m
[38;5;244mE/flutter (28753): #5      _FutureListener.handleValue (dart:async/future_impl.dart:152:18)[39;49m
[38;5;244mE/flutter (28753): #6      Future._propagateToListeners.handleValueCallback (dart:async/future_impl.dart:704:45)[39;49m
[38;5;244mE/flutter (28753): #7      Future._propagateToListeners (dart:async/future_impl.dart:733:32)[39;49m
[38;5;244mE/flutter (28753): #8      Future._complete (dart:async/future_impl.dart:530:7)[39;49m
[38;5;244mE/flutter (28753): #9      new Future.delayed.<anonymous closure> (dart:async/future.dart:312:16)[39;49m
[38;5;244mE/flutter (28753): #10     _rootRun (dart:async/zone.dart:1346:47)[39;49m
[38;5;244mE/flutter (28753): #11     _CustomZone.run (dart:async/zone.dart:1258:19)[39;49m
[38;5;244mE/flutter (28753): #12     _CustomZone.runGuarded (dart:async/zone.dart:1162:7)[39;49m
[38;5;244mE/flutter (28753): #13     _CustomZone.bindCallbackGuarded.<anonymous closure> (dart:async/zone.dart:1202:23)[39;49m
[38;5;244mE/flutter (28753): #14     _rootRun (dart:async/zone.dart:1354:13)[39;49m
[38;5;244mE/flutter (28753): #15     _CustomZone.run (dart:async/zone.dart:1258:19)[39;49m
[38;5;244mE/flutter (28753): #16     _CustomZone.bindCallback.<anonymous closure> (dart:async/zone.dart:1186:23)[39;49m
[38;5;244mE/flutter (28753): #17     Timer._createTimer.<anonymous closure> (dart:async-patch/timer_patch.dart:18:15)[39;49m
[38;5;244mE/flutter (28753): #18     _Timer._runTimers (dart:isolate-patch/timer_impl.dart:395:19)[39;49m
[38;5;244mE/flutter (28753): #19     _Timer._handleMessage (dart:isolate-patch/timer_impl.dart:426:5)[39;49m
[38;5;244mE/flutter (28753): #20     _RawReceivePortImpl._handleMessage (dart:isolate-patch/isolate_patch.dart:184:12)[39;49m
E/flutter (28753):

解决方法

这可能不是答案，但我仍然会指出可能导致您收到此错误的部分。

1. 您不必检查 if(mounted) 内的 initState 因为 initState 将在构建小部件树时运行，为简单起见，当您导航到此页面时，它将运行initState 先做，剩下的就做。

2. 如果您将 Tab bar 与 Tab Bar View 一起使用，请参阅此链接 https://flutter.dev/docs/cookbook/design/tabs 以了解如何使用 Flutter 标签栏。

3. 如果您所指的 tab items 是 Fl​​utter Tab Bar，那么您必须了解每当您浏览标签栏时，旧的标签视图将被处置，而新的标签您要查看的栏视图将被构建。这可能是您收到此错误的原因。

4. 对于每个标签栏视图来说，最好是一个新的有状态小部件。