【发布时间】：2020-04-12 12:59:25
【问题描述】：
当接收到特定错误状态且列表数据不为空时，我找不到在列内显示对话框警报的方法。警报对话框不涉及按钮单击，所有在线示例都包含一个按钮 onTap。
我想在列表数据不为空且设置了错误标志时显示警报。
下面是我的代码：
@override
Widget build(BuildContext context) {
return Scaffold(
key: scaffoldKey,
appBar: _myAppBar(),
body: RefreshIndicator(
key: _refreshIndicatorKey,
onRefresh: handleRefresh,
child: isListError && ordersListData.isEmpty
? _mainErrorWidget()
: Column(
children: <Widget>[
Expanded(
child: NotificationListener<ScrollNotification>(
onNotification: (ScrollNotification scrollInfo) {
if (hasMoreToLoad &&
!isListLoading &&
!isListError &&
scrollInfo.metrics.pixels ==
scrollInfo.metrics.maxScrollExtent) {
handleLoadMore();
}
},
child: ListView.builder(
itemCount: ordersListData.length,
itemBuilder: (BuildContext context, int index) {
return Card(
child: InkWell(
onTap: () {
Navigator.push(
context,
MaterialPageRoute(
builder: (context) => OrderDetailsPage(
baseurl: widget.baseurl,
username: widget.username,
password: widget.password,
id: ordersListData[index]["id"],
),
),
);
},
child: Row(
mainAxisAlignment: MainAxisAlignment.start,
mainAxisSize: MainAxisSize.max,
crossAxisAlignment:
CrossAxisAlignment.center,
children: <Widget>[
Expanded(
child: Padding(
padding: const EdgeInsets.all(10.0),
child: Column(
mainAxisAlignment:
MainAxisAlignment.start,
mainAxisSize: MainAxisSize.min,
crossAxisAlignment:
CrossAxisAlignment.start,
children: <Widget>[
_orderDate(
ordersListData[index]),
_orderIdAndBillingName(
ordersListData[index]),
_orderStatus(
ordersListData[index]),
_orderTotal(
ordersListData[index])
]),
),
)
]),
),
);
}),
),
),
if (isListLoading)
Container(
height: 60,
child: Center(
child: SpinKitPulse(
color: Colors.purple,
size: 50,
)),
),
_showErrorAlert(),
],
),
),
);
}
void _showErrorAlert() {
if (isListError && ordersListData.isNotEmpty) {
showDialog<void>(
context: context,
barrierDismissible: false,
builder: (BuildContext context) {
return AlertDialog(
title: Text("Retry"),
titlePadding: EdgeInsets.fromLTRB(15, 20, 15, 0),
content: Column(
children: <Widget>[
listError ?? Text(listError),
Text(
"Do you want to retry?",
style: Theme.of(context).textTheme.body1,
),
],
),
contentPadding: EdgeInsets.fromLTRB(15, 10, 15, 0),
actions: <Widget>[
FlatButton(
child: Text("No"),
onPressed: () {
Navigator.of(context).pop();
},
),
FlatButton(
child: Text("Yes"),
onPressed: () {
Navigator.of(context).pop();
fetchOrdersList();
},
)
],
);
});
}
}
我收到以下异常：
I/flutter (15007): ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter (15007): The following assertion was thrown building OrdersListPage(dirty, dependencies:
I/flutter (15007): [_LocalizationsScope-[GlobalKey#a6289], _InheritedTheme], state: _OrdersListPageState#ed7e3):
I/flutter (15007): setState() or markNeedsBuild() called during build.
I/flutter (15007): This Overlay widget cannot be marked as needing to build because the framework is already in the
I/flutter (15007): process of building widgets. A widget can be marked as needing to be built during the build phase
I/flutter (15007): only if one of its ancestors is currently building. This exception is allowed because the framework
I/flutter (15007): builds parent widgets before children, which means a dirty descendant will always be built.
I/flutter (15007): Otherwise, the framework might not visit this widget during this build phase.
I/flutter (15007): The widget on which setState() or markNeedsBuild() was called was:
I/flutter (15007): Overlay-[LabeledGlobalKey<OverlayState>#d7fb9]
I/flutter (15007): The widget which was currently being built when the offending call was made was:
I/flutter (15007): OrdersListPage
I/flutter (15007):
I/flutter (15007): The relevant error-causing widget was:
I/flutter (15007): OrdersListPage file:///C:/Users/itsga/Desktop/flutter/woocommerceadmin/lib/main.dart:121:13
I/flutter (15007):
I/flutter (15007): When the exception was thrown, this was the stack:
I/flutter (15007): #0 Element.markNeedsBuild.<anonymous closure> (package:flutter/src/widgets/framework.dart:3896:11)
I/flutter (15007): #1 Element.markNeedsBuild (package:flutter/src/widgets/framework.dart:3911:6)
I/flutter (15007): #2 State.setState (package:flutter/src/widgets/framework.dart:1168:14)
I/flutter (15007): #3 OverlayState.insertAll (package:flutter/src/widgets/overlay.dart:344:5)
I/flutter (15007): #4 OverlayRoute.install (package:flutter/src/widgets/routes.dart:44:24)
I/flutter (15007): #5 TransitionRoute.install (package:flutter/src/widgets/routes.dart:181:11)
I/flutter (15007): #6 ModalRoute.install (package:flutter/src/widgets/routes.dart:959:11)
I/flutter (15007): #7 NavigatorState.push (package:flutter/src/widgets/navigator.dart:1791:11)
I/flutter (15007): #8 showGeneralDialog (package:flutter/src/widgets/routes.dart:1634:65)
I/flutter (15007): #9 showDialog (package:flutter/src/material/dialog.dart:711:10)
I/flutter (15007): #10 _OrdersListPageState._showErrorAlert (package:woocommerceadmin/src/orders/widgets/OrdersListPage.dart:408:7)
I/flutter (15007): #11 _OrdersListPageState.build (package:woocommerceadmin/src/orders/widgets/OrdersListPage.dart:143:21)
I/flutter (15007): #12 StatefulElement.build (package:flutter/src/widgets/framework.dart:4334:27)
I/flutter (15007): #13 ComponentElement.performRebuild (package:flutter/src/widgets/framework.dart:4223:15)
I/flutter (15007): #14 Element.rebuild (package:flutter/src/widgets/framework.dart:3947:5)
I/flutter (15007): #15 BuildOwner.buildScope (package:flutter/src/widgets/framework.dart:2432:33)
I/flutter (15007): #16 WidgetsBinding.drawFrame (package:flutter/src/widgets/binding.dart:773:20)
I/flutter (15007): #17 RendererBinding._handlePersistentFrameCallback (package:flutter/src/rendering/binding.dart:283:5)I/flutter (15007): #18 SchedulerBinding._invokeFrameCallback (package:flutter/src/scheduler/binding.dart:1102:15)
I/flutter (15007): #19 SchedulerBinding.handleDrawFrame (package:flutter/src/scheduler/binding.dart:1041:9)
I/flutter (15007): #20 SchedulerBinding._handleDrawFrame (package:flutter/src/scheduler/binding.dart:957:5)
I/flutter (15007): #24 _invoke (dart:ui/hooks.dart:259:10)
I/flutter (15007): #25 _drawFrame (dart:ui/hooks.dart:217:3)
I/flutter (15007): (elided 3 frames from package dart:async)
I/flutter (15007):
I/flutter (15007): ════════════════════════════════════════════════════════════════════════════════════════════════════
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标签： flutter