如何解决颤振如何确定用户单击PopupMenuItem的ListView中的哪个ListTile?
我有一个包含ListTiles的ListView。每个图块代表我的用户数组中的一个用户。磁贴的尾部是PopupMenuButton。当用户单击一个PopupMenuItem时,应调用一个函数。到现在为止还挺好。我想在“ onSelected”中将相应用户的数据传递给一个函数。
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:cloud_functions/cloud_functions.dart';
import 'package:Flutter/material.dart';
class UserListMobilePortrait extends StatelessWidget {
final List<QueryDocumentSnapshot> users;
const UserListMobilePortrait({
Key key,this.users,}) : super(key: key);
@override
Widget build(BuildContext context) {
final HttpsCallable setRoleCallable = CloudFunctions.instance
.getHttpsCallable(functionName: 'setRoles')
..timeout = const Duration(seconds: 10);
final button = new PopupMenuButton(
itemBuilder: (_) => <PopupMenuItem<String>>[
new PopupMenuItem<String>(
child: const Text('Make Admin'),value: 'admin'),new PopupMenuItem<String>(
child: const Text('Make Editor'),value: 'editor'),],onSelected: (selectedItem) async {
try {
final HttpsCallableResult result = await setRoleCallable.call(
<String,dynamic>{
//'user' shall represent the user of the clicked ListTile,but how to pass it?
'email': user.data()['email'],'role': selectedItem,'permission': 'grant'
},);
print(result.data);
} on CloudFunctionsException catch (e) {
print('caught firebase functions exception');
print(e.code);
print(e.message);
print(e.details);
} catch (e) {
print('caught generic exception');
print(e);
}
});
return ListView(
children: users
.map((user) => ListTile(
title: Text(
(user.data()['email'] != null) ? user.data()['email'] : ""),subtitle: Row(
children: [
Text((user.data()['displayName'] != null)
? user.data()['displayName']
: ""),Container(
width: 6,),user.data()['isAdmin'] == true
? Chip(
label: Text('admin'),backgroundColor: Colors.orange[600],shadowColor: Colors.orange[900],)
: Text(''),user.data()['isEditor'] == true
? Chip(
label: Text('editor'),backgroundColor: Colors.blue[600],shadowColor: Colors.blue[900],trailing: button,))
.toList(),);
}
}
解决方法
了解您的问题,一个简单的解决方法是使用Listview Builder(也可以使用ListView Builder来优化应用程序的速度)
const List = ["Hello","World","Temp"]
ListView.builder(
itemBuilder: (context,index) {
//return (Your widget [a list tile preferably and use onTap(and access the index
in the function)])
return(ListTile(onTap:(){
print(List[index]);
//you can access the index and use the main list to get its following data
};
};
这将锻炼:)
,我的解决方案是将以前的final按钮移到自己的类上。这样我就可以将数据传递给构造函数了。
UserPopupMenuButton
import 'package:cloud_firestore/cloud_firestore.dart';
import 'package:cloud_functions/cloud_functions.dart';
import 'package:flutter/material.dart';
class UserPopupMenuButton extends StatelessWidget {
final QueryDocumentSnapshot user;
const UserPopupMenuButton({
Key key,this.user,}) : super(key: key);
@override
Widget build(BuildContext context) {
final HttpsCallable setRoleCallable = CloudFunctions.instance
.getHttpsCallable(functionName: 'setRoles')
..timeout = const Duration(seconds: 10);
return PopupMenuButton(
itemBuilder: (_) => <PopupMenuItem<String>>[
new PopupMenuItem<String>(
child: const Text('Make Admin'),value: 'admin'),new PopupMenuItem<String>(
child: const Text('Make Editor'),value: 'editor'),],onSelected: (selectedItem) async {
try {
final HttpsCallableResult result = await setRoleCallable.call(
<String,dynamic>{
'email': user.data()['email'],'role': selectedItem,'permission': 'grant'
},);
print(result.data);
} on CloudFunctionsException catch (e) {
print('caught firebase functions exception');
print(e.code);
print(e.message);
print(e.details);
} catch (e) {
print('caught generic exception');
print(e);
}
});
}
}
并将其用作ListTile的结尾:
trailing: UserPopupMenuButton(user: user),
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