Future Builder在setState上重建列表视图

Question

我正试图在使用Future Builder从api获取数据的列表中添加收藏夹按钮。然而，当我点击InkWell小部件标记为我的收藏夹时，它会重新加载列表，收藏夹按钮的颜色不会改变，而且似乎setState也不会改变_isFavorite值

未来建设者

Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
leading: IconButton(
icon: Icon(Icons.arrow_back),
onPressed: () => Navigator.of(context).pop(),
),
title: FittedBox(fit: BoxFit.fill, child: Text(getTranslated(context, 'derangement'))),
backgroundColor: Colors.red),
backgroundColor: Color(0xfff0f0f0),
body: Column(
mainAxisAlignment: MainAxisAlignment.start,
children: <Widget>[
SizedBox(height: 20),
buildHeader(widget.productName, Colors.lightBlue),
SizedBox(height: 20),
FutureBuilder<List>(
future: vapi.getDerangement(widget.endpoint, widget.productId),
initialData: List(),
builder: (context, snapshot) {
return futureHandler(snapshot, context, _expansionTile(snapshot));
},
),
],
),
);
}

ListView

Widget _expansionTile(AsyncSnapshot snapshot) {
return Flexible(
child: ListView.builder(
padding: const EdgeInsets.all(10.0),
itemCount: snapshot.data == null ? 0 : snapshot.data.length,
scrollDirection: Axis.vertical,
shrinkWrap: true,
itemBuilder: (context, i) {
bool _isFavourite = snapshot.data[i].isFavourite;
return Row(
children: <Widget>[
InkWell(
splashColor: Colors.yellow,
highlightColor: Colors.red,
child: Icon(
_isFavourite ? Icons.favorite : Icons.favorite_border,
size: 40,
color: _isFavourite ? Colors.red : null,
),
onTap: () {
setState(() {
_isFavourite = !_isFavourite;
});
},
),
Expanded(
child: SingleChildScrollView(
child: Container(
decoration: BoxDecoration(
borderRadius: BorderRadius.circular(25),
color: Colors.white54,
),
child: ExpansionTile(
title:
Text(snapshot.data[i].substanceName, style: TextStyle(fontSize: 20, fontWeight: FontWeight.bold)),
subtitle: Text(snapshot.data[i].name),
children: <Widget>[
SizedBox(
height: 200,
child: SingleChildScrollView(child: Text(snapshot.data[i].references)),
),
],
),
margin: EdgeInsets.symmetric(vertical: 10, horizontal: 2),
padding: EdgeInsets.symmetric(vertical: 5, horizontal: 5),
)))
],
);
},
));
}

Answer 1

future: vapi.getDerangement(widget.endpoint, widget.productId),

不要那样做。这将调用此方法，并在每次调用build方法时生成新future。

在initState中调用此方法，并将返回值保存在变量中。然后将这个变量传递给FutureBuilder，所以如果多次调用build，它仍然是同一个未来，而不是每次都是新的。