我在尝试刷新 FutureBuilder 中的 ListView 时遇到了问题，我无法刷新它，而不是通过使用 setState，而不是其他任何东西，有更多经验的人能否建议我使用 FutureBuilder 或 setState 的方式有什么问题？
这是我遇到问题的代码：
class ChatScreen extends StatefulWidget {
@override
_ChatScreenState createState() => _ChatScreenState();
}
class _ChatScreenState extends State<ChatScreen> {
String contact_name;
int contact_id;
String str_id;
List<Align> messagesList = [];
Align messageUnit;
int ownID;
String ownName;
double height;
double width;
final TextEditingController messageGetter = TextEditingController();
@override
void initState() {
super.initState();
final res = Variables.getContactName();
contact_name = res;
final res_2 = Variables.getContactID();
contact_id = res_2;
str_id = res_2.toString();
final res_3 = Variables.getOwnID();
ownID = res_3;
final res_4 = Variables.getOwnName();
ownName = res_4;
}
@override
Widget build(BuildContext context) {
return FutureBuilder(
future:getMessages(),
builder: (BuildContext context, AsyncSnapshot<String> snapshot) {
if (snapshot.hasData) {
final data = snapshot.data;
width = MediaQuery
.of(context)
.size
.width;
height = MediaQuery
.of(context)
.size
.height;
print(data);
return Scaffold(
appBar:
AppBar(
title: Text(contact_name),
backgroundColor: Color(0xD3232323),
),
body:
Column(
children: [
Expanded(
child: ListView(
children: messagesList,
reverse: true,
),
),
Container(
child: Row(
children: [
Expanded(
child: Padding(
child: TextField(
controller: messageGetter,
decoration: InputDecoration(
border: OutlineInputBorder(
borderRadius: BorderRadius.circular(20.0),
borderSide: BorderSide(),
),
),
),
padding: EdgeInsets.fromLTRB(8, 8, 8, 8),
),
),
Container(
child: Padding(
child: OutlinedButton(
onPressed: () {
sendMessage();
setState(() {
getMessages();
});
},
child: Text("+"),
style: ButtonStyle(
),
),
padding: EdgeInsets.fromLTRB(8, 8, 8, 8),
),
),
],
),
),
],
)
);
}
if (snapshot.hasError) {
return Scaffold(
appBar: AppBar(
title: Text(contact_name),
backgroundColor: Color(0xD3232323),
),
body:
Container(
child:
Align(alignment: Alignment.center,
child:
Text("Error"),
),
),
);
}
if (snapshot.connectionState != ConnectionState.done) {
return Scaffold(
appBar: AppBar(
title: Text(contact_name),
backgroundColor: Color(0xD3232323),
),
body:
Container(
child:
Align(alignment: Alignment.center,
child:
CircularProgressIndicator(
),
),
),
);
}
else
return Text("Meow");
}
);
}
Future<String> getMessages() async{
final result = await context.read<TelegramService>().send(
TdApi.GetChatHistory(chatId: contact_id, limit: 1, )
);
print(result);
final res = await context.read<TelegramService>().send(
TdApi.GetChatHistory(chatId: contact_id, limit: 999)
);
TdApi.Messages messages = res;
messagesList.clear();
for(var i = 0; i < messages.totalCount; i++) {
TdApi.Message message = messages.messages[i];
TdApi.MessageContent text = message.content;
TdApi.MessageText textContent = text;
TdApi.FormattedText textFinal = textContent.text;
TdApi.MessageSenderUser messageSender = message.sender;
if (messageSender.userId == ownID) {
messageUnit = Align (
alignment: Alignment.centerRight,
child: Padding(
padding: EdgeInsets.fromLTRB(0, 8, 0, 8),
child: OutlinedButton(
child: Text(textFinal.text,
style: TextStyle(
color: Color(0xD3232323),
),
),
style: ButtonStyle(
backgroundColor: MaterialStateProperty.all(Color(0xD300FFEA)),
),
),
),
);
}
else {
messageUnit = Align (
alignment: Alignment.centerLeft,
child: Padding(
padding: EdgeInsets.fromLTRB(0, 8, 0, 8),
child: OutlinedButton(
child: Text(textFinal.text),
style: ButtonStyle(
backgroundColor: MaterialStateProperty.all(Color(0xD3383838)),
),
),
),
);
}
messagesList.add(messageUnit);
}
return "Messages Retrieved";
}
sendMessage() async {
TdApi.FormattedText messageText = TdApi.FormattedText(text: messageGetter.text, entities: []);
TdApi.MessageSendOptions messageSendOptions = TdApi.MessageSendOptions(disableNotification: false) ;
TdApi.InputMessageText message = TdApi.InputMessageText(text: messageText);
final result = await context.read<TelegramService>().send(
TdApi.SendMessage(chatId: contact_id, inputMessageContent: message, options: messageSendOptions),
);
print(result);
messageGetter.clear();
}
}