在颤振/飞镖中添加联系人的电话号码

Question

我正在颤振中构建一个可选的复选框联系人列表，但如果联系人只有电子邮件而没有号码，则会抛出错误。我想创建一个循环，将"99999"的数字添加到联系人电话号码(如果他们没有(。请有人指导我解释我应该改变什么才能完成这项工作吗？我已经试过了，但我对颤振很陌生，所以我对语法等并不完全确定......

这是我尝试将函数放入的代码部分。

setMissingNo()async {
Iterable<Contact> contactsToLoop = (await ContactsService.getContacts()).toList();
contactsToLoop.forEach((Contact) { contactsToLoop = []..add(Item.fromMap({'label': 'work', 'value': 99999})); });
}
//fetch contacts from setMissingNo
getAllContacts() async{
Iterable<Contact> _contacts = (await ContactsService.getContacts()).toList(); 
setState(() {
contacts = _contacts;
}
);
}

这是我的整个代码

import 'package:flutter/material.dart';
// TODO: make it ask for permissions otherwise the app crashes
import 'package:contacts_service/contacts_service.dart';
class Home extends StatefulWidget {
@override
_HomeState createState() => _HomeState();
}
class _HomeState extends State<Home> {
List<Contact> contacts = [];
List<Contact> contactsFiltered = [];
TextEditingController searchController = new TextEditingController();
@override
void initState() {
super.initState();
getAllContacts();
searchController.addListener(() => filterContacts());
}
//remove the +'s and spaces from a phone number before its searched
String flattenPhoneNumber(String phoneStr) {
return phoneStr.replaceAllMapped(RegExp(r'^(+)|D'), (Match m) {
return m[0] == "+" ? "+" : "";
});
}

//loop and set all contacts without numbers to 99999, pass new list to getAllContacts
setMissingNo()async {
Iterable<Contact> contactsToLoop = (await ContactsService.getContacts()).toList();
contactsToLoop.forEach((Contact) { contactsToLoop = []..add(Item.fromMap({'label': 'work', 'value': 99999})); });
}
//fetch contacts from setMissingNo
getAllContacts() async{
Iterable<Contact> _contacts = (await ContactsService.getContacts()).toList(); 
setState(() {
contacts = _contacts;
}
);
}

//filtering contacts function to match search term
filterContacts() {
List<Contact> _contacts = [];
_contacts.addAll(contacts);
if (searchController.text.isNotEmpty) {
_contacts.retainWhere((contact) {
String searchTerm = searchController.text.toLowerCase();
String searchTermFlatten = flattenPhoneNumber(searchTerm);
String contactName = contact.displayName.toLowerCase();
bool nameMatches = contactName.contains(searchTerm);
if (nameMatches == true) {
return true;
}
if (searchTermFlatten.isEmpty) {
return false;
}
var phone = contact.phones.firstWhere((phn) {
String phnFlattened = flattenPhoneNumber(phn.value);
return phnFlattened.contains(searchTermFlatten);
}, orElse: () => null);
return phone != null;
});
setState(() {
contactsFiltered = _contacts;
});
}
}

final selectedContacts = Set<Contact>();
@override
Widget build(BuildContext context) {
bool isSearching = searchController.text.isNotEmpty;
return Scaffold(
body: SafeArea(
child: Column(
children: <Widget>[
AppBar(
title: Text('Create Group'),
),
Container(
child: TextField(
controller: searchController,
decoration: InputDecoration(
labelText: 'Search Contacts',
border: OutlineInputBorder(
borderSide: new BorderSide(
color: Theme.of(context).primaryColor
)
),
prefixIcon: Icon(
Icons.search,
color: Theme.of(context).primaryColor
)
),
),
),
Expanded( child: ListView.builder(
shrinkWrap: true,
itemCount: isSearching == true ? contactsFiltered.length : contacts.length,
itemBuilder: (context, index) {
Contact contact = isSearching == true ? contactsFiltered[index] : contacts[index];
//TODO: make it so when you clear your search, all items appear again & when you search words it works
return CheckboxListTile(
title: Text(contact.displayName),
subtitle: Text(
contact.phones.elementAt(0).value
),                      
value: selectedContacts.contains(contact),
onChanged: (bool value) { 
if (value) { 
selectedContacts.add(contact); 
} else {
selectedContacts.remove(contact); 
}
setState((){}); 
// TODO: add in function to add contact ID to a list
});
},
),
/*new Expanded(
child: Align(
alignment: Alignment.bottomLeft,
child: BottomNavigationBar(  
currentIndex: _currentIndex,   
items: const <BottomNavigationBarItem>[
//TODO: create new contact functionality to add someone by name + email
BottomNavigationBarItem(
icon: Icon(Icons.add),
title: Text('Add Contact'),
),
BottomNavigationBarItem(
icon: Icon(Icons.create),
title: Text('Create Group'),
),
],  
onTap: (index) {
setState(() {
_currentIndex = index;
});     
}
)
)
)*/
)
],
)
),
);
}
}

Answer 1

更新设备上列出的所有联系人可能需要很长时间，具体取决于设备联系人列表的大小。添加任务正在 UI 线程上完成。您可能需要考虑对任务使用隔离，以转移 UI 线程中的负载。如果您还可以提供您遇到的错误，它将帮助我们了解问题。

另一件事是，您处理问题的方式可能不切实际。真的有必要给联系人写一个占位符电话号码吗？此问题可能源于尝试从联系人处获取号码，但 Object 返回 null。也许您可能希望考虑仅在选择联系人时更新电话号码。