当我尝试使用提供程序从此item(like 0 index item)
中删除listview
时,它从列表中删除了最后一项。当我从列表中删除最后一个元素时,成功删除了最后一个项目。我有点困惑为什么我会发生这种问题。
我在这里发布了一些代码,请检查并给出您的宝贵建议。同时在此视频上演示发生了什么问题
链接:https://drive.google.com/file/d/1UYl8Z7vEj_tZCaYzqe0VqZL2iMla5nIZ/view?usp=sharing
预期结果:每当用户按下删除按钮,然后删除该特定行(项目)。
删除方法:-这是删除方法,当用户从列表中按Delete按钮时将调用它。
Future<void> acceptdeclinerequest(String requestStatus,int requestId) async{
String token = await CustomPreferences.getpreferences('token');
Map<String, String> requestHeaders;
if (token.isNotEmpty) {
requestHeaders = {
'Accept': 'application/json',
'Authorization': 'Bearer ' + token
};
} else {
requestHeaders = {
'Accept': 'application/json',
};
}
var reqdata = {
"request_id":requestId.toString(),
"status":requestStatus
};
print('accept request data is $reqdata');
try
{
final response =
await http.post(Connection.url + 'respond-place-request', headers: requestHeaders,body: reqdata);
if (response.statusCode == 200) {
Map<String, dynamic> responseJson = json.decode(response.body);
final existingProductIndex = _items.indexWhere((prod) => prod.id == requestId);
var existingProduct = _items[existingProductIndex];
_items.removeAt(existingProductIndex);
notifyListeners();
return responseJson;
} /*else if (response.statusCode == 500) {
return servererrorresponse;
}*/
} catch (exception) {
throw exception;
}
}
主窗口小部件类:这是我定义Listview
小窗口的主窗口小部件类。我已经使用provider从api中获取数据,该api是用模态类编写的,以Listview
填充,而Listview child widgets
是单独的类RequestWidgets
。在本类(class)中,我传递了rowitems
数据以listview
显示。GlobalKey<ScaffoldState> _scaffoldKey = GlobalKey<ScaffoldState>();
var connectionstatus;
var product;
var _isInit = true;
var _isLoading = false;
@override
void initState() {
super.initState();
}
@override
void didChangeDependencies() {
// TODO: implement didChangeDependencies
if (_isInit) {
setState(() {
_isLoading = true;
});
Provider.of<BandRequestModal>(context).getBandRequestList().then((_) {
setState(() {
_isLoading = false;
});
});
}
_isInit = false;
super.didChangeDependencies();
}
@override
Widget build(BuildContext context) {
connectionstatus = Provider.of<ConnectivityResult>(context);
product = Provider.of<BandRequestModal>(context, listen: false);
// getRequestData();
return WillPopScope(
onWillPop: _onWillPop,
child: Scaffold(
key: _scaffoldKey,
appBar: CustomAppbar(
_scaffoldKey, Constants.requests, 100.0, filterRecord),
endDrawer: MenuDrawer(),
body:
/*(connectionstatus == ConnectivityResult.wifi ||
connectionstatus == ConnectivityResult.mobile)
? */
Consumer<BandRequestModal>(builder: (context, modal, child) {
return !_isLoading
? Container(child: LayoutBuilder(builder:
(BuildContext context, BoxConstraints constraints) {
return Container(
height: constraints.maxHeight,
child: modal.item.length > 0
? ListView.builder(
padding:
EdgeInsets.only(top: 10.0, bottom: 0.0),
itemCount: modal.item.length,
shrinkWrap: true,
// physics: NeverScrollableScrollPhysics(),
itemBuilder: (context, int i) {
return RequestWidgets(data: modal.item[i]);
})
: Center(
child: new Text(
Constants.norecordfound,
style: TextStyle(
fontSize: 20.0,
fontWeight: FontWeight.bold),
),
),
// ],
// ),
);
}))
: Comman.loadingIndicator(Theme.of(context).primaryColor);
})
// : Comman.nointernetconnection(context)
// FutureBuilder<BandRequestModal>(
// future: Connection.bandRequestList(),
// builder: (context, snapshot) {
// switch (snapshot.connectionState)
// {
// case ConnectionState.none:
// break;
// case ConnectionState.waiting:
// return Comman.loadingIndicator(
// Theme.of(context).primaryColor);
// break;
// case ConnectionState.active:
// break;
// case ConnectionState.done:
// if (snapshot.hasError) {
// return Center(
// child: new Text(Constants.servererror),
// );
// }else if(snapshot.data==null){
// return Center(
// child: new Text(Constants.servererror),
// );
// } else if (snapshot.data.data.length == 0) {
// return Center(
// child: new Text(
// Constants.norecordfound,
// style: TextStyle(
// fontSize: 20.0, fontWeight: FontWeight.bold),
// ),
// );
// } else {
// return ListView.builder(
// padding:
// EdgeInsets.only(top: 10.0, bottom: 60.0),
// itemCount: snapshot.data.data.length,
// shrinkWrap: true,
// physics: NeverScrollableScrollPhysics(),
// itemBuilder: (context, int i) {
// return RequestWidgets(data:snapshot.data.data[i]);
// });
// }
// break;
// }
// }):Comman.nointernetconnection(context)
));
}
子级窗口小部件类:这是listview的行项目类。在此类中,我们使用了许多小部件来显示位置数据。class _RequestWidgetsState extends State<RequestWidgets> {
var getData;
var product;
@override
void initState() {
// TODO: implement initState
getData = widget.data;
super.initState();
}
@override
Widget build(BuildContext context) {
product = Provider.of<BandRequestModal>(context, listen: false);
return Container(
// alignment: Alignment.topLeft,
margin: EdgeInsets.only(top: 5.0),
child: ListTile(
// contentPadding: EdgeInsets.zero,
key: ObjectKey(getData),
leading: CircleAvatar(
radius: 30,
backgroundColor: Colors.transparent,
child: ClipOval(
child: (getData.placeDetails.image != null &&
getData.placeDetails.image != '')
? Image.network(
getData.placeDetails.image,
width: 90,
height: 90,
fit: BoxFit.cover,
)
: Image.asset(
Res.defaultImage,
width: 90,
height: 90,
fit: BoxFit.cover,
)),
),
title: Row(
mainAxisAlignment: MainAxisAlignment.start,
children: <Widget>[
Expanded(
child: Text(getData.placeDetails.name,
style: TextStyle(
fontSize: 16.0,
fontFamily: 'Metropolis',
color: CustomColors.commentTitleColor))),
],
),
subtitle: Container(
margin: EdgeInsets.only(top: 1.0),
child: Column(children: <Widget>[
Container(
margin: EdgeInsets.only(top: 1.0),
child: Row(children: <Widget>[
Expanded(
child: Text(getData.placeDetails.address,
style: TextStyle(
fontSize: 15.0,
height: 1.2,
fontFamily: 'Metropolis',
color: CustomColors.commentSubtitleColor))),
]),
),
Container(
margin: EdgeInsets.only(top: 15.0, bottom: 15.0),
child: Row(
mainAxisAlignment: MainAxisAlignment.end,
children: <Widget>[],
)),
Divider(
color: CustomColors.commentlineColor,
thickness: 0.8,
)
])),
trailing: Row(
mainAxisSize: MainAxisSize.min,
children: <Widget>[
GestureDetector(
child: CircleAvatar(
radius: 20,
backgroundColor: Colors.green,
child: Icon(
Icons.check,
color: Colors.white,
),
),
onTap: () {
acceptrejectpopup('1');
// {
// print('accept data $data');
// Comman.hideLoading(context);
// Comman.showSnakBar(data['message'],context);
// });
},
),
SizedBox(
width: 15.0,
),
GestureDetector(
child: CircleAvatar(
backgroundColor: Colors.red,
child: Icon(
Icons.clear,
color: Colors.white,
),
),
onTap: () {
// Comman.showLoading(context);
acceptrejectpopup('0');
/*product.acceptdeclinerequest('0',getData.id.toString()).then((data){
print('decline data $data');
Comman.hideLoading(context);
Comman.showSnakBar(data['message'],context);
});*/
},
)
],
),
),
);
}
//accept and reject
void acceptRejectRequest(String requestStatus) async {
try {
var response =
await product.acceptdeclinerequest(requestStatus, getData.id);
if (response['status'] == Constants.status_true) {
Comman.hideLoading(context);
Comman.showSnakBar(response['message'], context);
// setState(() {});
} else {
Comman.hideLoading(context);
}
} catch (exception) {
Comman.hideLoading(context);
Comman.showSnakBar(Constants.servererror, context);
}
}
//request accept/reject popup
Future<void> acceptrejectpopup(String reqStatus) {
return showDialog(
context: context,
builder: (context) => new AlertDialog(
title: new Text('Alert!',
style: TextStyle(color: Colors.black, fontWeight: FontWeight.bold)),
content: new Text(reqStatus == '1'
? Constants.reqAcceptmessage
: Constants.reqRejectemessage),
actions: <Widget>[
new FlatButton(
onPressed: () => Navigator.of(context).pop(),
child: new Text(Constants.notxt),
),
new FlatButton(
onPressed: () {
Navigator.of(context).pop();
Comman.showLoading(context);
acceptRejectRequest(reqStatus);
},
child: new Text(Constants.yestxt),
),
],
),
);
}
最佳答案
提供程序运行良好,问题是当提供程序通知消费者ListView
更新子级时,但是StatefulWidget
检查它们的类型相同(它们都是RequestWidget
),因此它们只是自我更新(如果您不这样做)提供StatefulWidget
的密钥,他们将尝试检查它们是否相同,并通过didChangeDependencies
方法进行更新),但是您正在initState中更新getData
var(它将仅调用一次),因此即使使用者更新了值(value)不会。像这样尝试
@override
void initState() {
// TODO: implement initState
//getData = widget.data; not here
super.initState();
}
@override
void didChangeDependencies() {
// TODO: implement initState
getData = widget.data; //update it here
super.didChangeDependencies();
}
另一种选择是在itemBuilder中构建窗口小部件时提供特定的密钥,以便使用者更新时对其进行相应更改。return RequestWidgets(key: ValueKey(modal.item[i].id),data: modal.item[i]);
// Or some value unique for each item