[英]flutter showdialog setState() or markNeedsBuild() called during build
[英]Flutter: setState() or markNeedsBuild() called during build from onPressed
当有人单击 ListTile 的尾随图标时,我试图显示一个对话框,但我收到“在构建期间调用的 setState() 或 markNeedsBuild()”错误消息。 这是卡片(在 MyCard 类中)和 function 给我错误消息 (checkCard):
static Widget buildCard(MyCard card, BuildContext context) {
var dateFormat = DateFormat('MM/dd/yyyy');
return Column(
children: [
Align(
alignment: Alignment.centerRight,
child: Text(dateFormat.format(card.createdOn.toDate()))),
const SizedBox(height: 6),
ListTile(
shape:
RoundedRectangleBorder(borderRadius: BorderRadius.circular(30)),
tileColor: Colors.white,
leading: CircleAvatar(child: Text(card.subCategory)),
title: Text("Score: " + card.score + " Misses: " + card.misses),
subtitle: card.comment.isNotEmpty
? Text("Comment(s): " + card.comment)
: null,
trailing: IconButton(
icon: const Icon(Icons.arrow_forward_ios),
onPressed: checkCard(card, context)),
),
const SizedBox(height: 18),
],
);
}
static checkCard(MyCard card, BuildContext context) {
showDialog(context: context, builder: (context) => const Text("Hello"));
}
它们是从 StatefulWidgets 构建的,如下所示:
@override
Widget build(BuildContext context) =>
FutureBuilder<List<Map<String, dynamic>>>(
future: MyCard.getData(3, Utils.ddfDropdown)!
.whenComplete(() => setState(() {
isLoading = false;
})),
builder: ((context, snapshot) {
if (snapshot.hasData && snapshot.data!.isNotEmpty) {
return FutureBuilder<List<MyCard>>(
future: MyCard.readData(snapshot.data),
builder: (context, cards) {
if (cards.hasData) {
final card = cards.data!;
return Expanded(
child: ListView.builder(
padding: const EdgeInsets.all(16),
itemCount: card.length,
itemBuilder: (context, index) {
return MyCard.buildCard(card[index], context); //Cards being built here
},
),
);
}
我在别处查找了这个错误; 一项建议是执行以下操作:
static checkCard(MyCard card, BuildContext context) {
WidgetsBinding.instance.addPostFrameCallback((_) {
showDialog(context: context, builder: (context) => const Text("Hello"));
});
}
但似乎这样做会调用 showDialog 而不必单击尾随的 IconButton,然后屏幕就会变黑。 另一个建议是做类似的事情:
static checkCard(MyCard card, BuildContext context) {
SchedulerBinding.instance.addPostFrameCallback((_) {
showDialog(context: context, builder: (context) => const Text("Hello"));
});
}
但同样的事情发生了(似乎无需单击即可调用 showDialog 并且屏幕变黑)。
问题来自于在构建小部件时调用方法。
onPressed: checkCard(card, context)),
你喜欢在按下时调用方法,所以它可以是
onPressed:()=> checkCard(card, context)),
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