Dart 错误状态:在flutter中从addStream添加项目时,无法关闭主题
我使用RxDart来观察更改并相应地更新UI。当应用程序启动时,我正在进行网络呼叫并成功获取数据,观察更改并相应更新UI。但是当我在关闭屏幕时处理Dart 错误状态:在flutter中从addStream添加项目时,无法关闭主题,dart,flutter,rxdart,Dart,Flutter,Rxdart,我使用RxDart来观察更改并相应地更新UI。当应用程序启动时,我正在进行网络呼叫并成功获取数据,观察更改并相应更新UI。但是当我在关闭屏幕时处理主题时。它给出了以下错误: ══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════ I/flutter (15524): The following StateError was thrown while f
主题时。它给出了以下错误:
══╡ EXCEPTION CAUGHT BY WIDGETS LIBRARY ╞═══════════════════════════════════════════════════════════
I/flutter (15524): The following StateError was thrown while finalizing the widget tree:
I/flutter (15524): Bad state: You cannot close the subject while items are being added from addStream
下面是bloc类:
class MovieDetailBloc {
final _repository = Repository();
final _movieId = PublishSubject<int>();
final _trailers = BehaviorSubject<Future<TrailerModel>>();
Function(int) get fetchTrailersById => _movieId.sink.add;
Observable<Future<TrailerModel>> get movieTrailers => _trailers.stream;
MovieDetailBloc() {
_movieId.stream.transform(_itemTransformer()).pipe(_trailers);
}
dispose() {
_movieId.close();
_trailers.close();
}
_itemTransformer() {
return ScanStreamTransformer(
(Future<TrailerModel> trailer, int id, int index) {
print(index);
trailer = _repository.fetchTrailers(id);
return trailer;
},
);
}
}
classmoviedetailbloc{
最终_repository=repository();
最终_movieId=PublishSubject();
最终_=行为主体();
函数(int)get fetchtrailersbyd=>\u movieId.sink.add;
可观察的get movieTrailers=>\u trailes.stream;
MovieDetailBloc(){
_movieId.stream.transform(_itemTransformer()).pipe(_trailes);
}
处置{
_movieId.close();
_拖车。关闭();
}
_itemTransformer(){
回程扫描变压器(
(未来预告片,整数id,整数索引){
打印(索引);
拖车=_repository.fetchtrailes(id);
返回拖车;
},
);
}
}
这是UI屏幕,我将其称为:
import 'dart:async';
import 'package:flutter/material.dart';
import '../blocs/movie_detail_bloc_provider.dart';
import '../models/trailer_model.dart';
class MovieDetail extends StatefulWidget {
final posterUrl;
final description;
final releaseDate;
final String title;
final String voteAverage;
final int movieId;
MovieDetail({
this.title,
this.posterUrl,
this.description,
this.releaseDate,
this.voteAverage,
this.movieId,
});
@override
State<StatefulWidget> createState() {
return MovieDetailState(
title: title,
posterUrl: posterUrl,
description: description,
releaseDate: releaseDate,
voteAverage: voteAverage,
movieId: movieId,
);
}
}
class MovieDetailState extends State<MovieDetail> {
final posterUrl;
final description;
final releaseDate;
final String title;
final String voteAverage;
final int movieId;
MovieDetailBloc bloc;
MovieDetailState({
this.title,
this.posterUrl,
this.description,
this.releaseDate,
this.voteAverage,
this.movieId,
});
@override
void didChangeDependencies() {
bloc = MovieDetailBlocProvider.of(context);
bloc.fetchTrailersById(movieId);
super.didChangeDependencies();
}
@override
void dispose() {
bloc.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return Scaffold(
body: NestedScrollView(
headerSliverBuilder: (BuildContext context, bool innerBoxIsScrolled) {
return <Widget>[
SliverAppBar(
expandedHeight: 220.0,
floating: false,
pinned: false,
flexibleSpace: FlexibleSpaceBar(
background: Image.network(
"https://image.tmdb.org/t/p/w500$posterUrl",
fit: BoxFit.cover,
)),
),
];
},
body: Padding(
padding: const EdgeInsets.all(10.0),
child: Column(
crossAxisAlignment: CrossAxisAlignment.start,
children: <Widget>[
Container(margin: EdgeInsets.only(top: 5.0)),
Text(
title,
style: TextStyle(
fontSize: 25.0,
fontWeight: FontWeight.bold,
),
),
Container(margin: EdgeInsets.only(top: 8.0, bottom: 8.0)),
Row(
children: <Widget>[
Icon(
Icons.favorite,
color: Colors.red,
),
Container(
margin: EdgeInsets.only(left: 1.0, right: 1.0),
),
Text(
voteAverage,
style: TextStyle(
fontSize: 18.0,
),
),
Container(
margin: EdgeInsets.only(left: 10.0, right: 10.0),
),
Text(
releaseDate,
style: TextStyle(
fontSize: 18.0,
),
),
],
),
Container(margin: EdgeInsets.only(top: 8.0, bottom: 8.0)),
Text(description),
Container(margin: EdgeInsets.only(top: 8.0, bottom: 8.0)),
Text(
"Trailer",
style: TextStyle(
fontSize: 25.0,
fontWeight: FontWeight.bold,
),
),
Container(margin: EdgeInsets.only(top: 8.0, bottom: 8.0)),
StreamBuilder(
stream: bloc.movieTrailers,
builder:
(context, AsyncSnapshot<Future<TrailerModel>> snapshot) {
if (snapshot.hasData) {
return FutureBuilder(
future: snapshot.data,
builder:
(context, AsyncSnapshot<TrailerModel> itemSnapShot) {
if (itemSnapShot.hasData) {
if (itemSnapShot.data.results.length > 0)
return trailerLayout(itemSnapShot.data);
else
return noTrailer(itemSnapShot.data);
} else {
return CircularProgressIndicator();
}
},
);
} else {
return CircularProgressIndicator();
}
},
),
],
),
),
),
);
}
Widget noTrailer(TrailerModel data) {
return Center(
child: Container(
child: Text("No trailer available"),
),
);
}
}
Widget trailerLayout(TrailerModel data) {
return Row(
children: <Widget>[
Expanded(
child: Column(
children: <Widget>[
Container(
margin: EdgeInsets.all(5.0),
height: 100.0,
color: Colors.grey,
),
Text(
data.results[0].name,
maxLines: 1,
overflow: TextOverflow.ellipsis,
),
],
),
),
Expanded(
child: Column(
children: <Widget>[
Container(
margin: EdgeInsets.all(5.0),
height: 100.0,
color: Colors.grey,
),
Text(
data.results[1].name,
maxLines: 1,
overflow: TextOverflow.ellipsis,
),
],
),
),
],
);
}
导入'dart:async';
进口“包装:颤振/材料.省道”;
导入“../blocs/movie_detail_bloc_provider.dart”;
导入“../models/trailer_model.dart”;
类MovieDetail扩展StatefulWidget{
最后一个月;
最后说明;
最终发布日期;
最后的字符串标题;
最终字符串voteAverage;
最终国际电影ID;
电影细节({
这个名字,
这是posterUrl,
这个.说明,,
这个,发布日期,
这是平均值,
这个,电影ID,
});
@凌驾
状态createState(){
返回电影详细信息状态(
标题:标题,,
posterUrl:posterUrl,
描述:描述,
releaseDate:releaseDate,
voteAverage:voteAverage,
电影ID:movieId,
);
}
}
类MovieDetailState扩展了状态{
最后一个月;
最后说明;
最终发布日期;
最后的字符串标题;
最终字符串voteAverage;
最终国际电影ID;
电影集团;
电影状态({
这个名字,
这是posterUrl,
这个.说明,,
这个,发布日期,
这是平均值,
这个,电影ID,
});
@凌驾
void didChangeDependencies(){
bloc=MovieDetailBlocProvider.of(上下文);
集团。fetchTrailersById(电影ID);
super.didChangeDependencies();
}
@凌驾
无效处置(){
集团处置();
super.dispose();
}
@凌驾
小部件构建(构建上下文){
返回脚手架(
正文:嵌套滚动视图(
headerSliverBuilder:(BuildContext上下文,boolInnerBoxIsCrolled){
返回[
滑杆(
扩展高度:220.0,
浮动:假,
错,,
flexibleSpace:FlexibleSpaceBar(
背景:Image.net(
"https://image.tmdb.org/t/p/w500$posterUrl“,
适合:BoxFit.cover,
)),
),
];
},
主体:填充物(
填充:常数边集全部(10.0),
子:列(
crossAxisAlignment:crossAxisAlignment.start,
儿童:[
容器(边距:仅限边集(顶部:5.0)),
正文(
标题
样式:TextStyle(
字体大小:25.0,
fontWeight:fontWeight.bold,
),
),
容器(仅限边缘集(顶部:8.0,底部:8.0)),
划船(
儿童:[
图标(
我的最爱,
颜色:颜色,红色,
),
容器(
边距:仅限边集(左:1.0,右:1.0),
),
正文(
voteAverage,
样式:TextStyle(
字体大小:18.0,
),
),
容器(
边距:仅限边集(左:10.0,右:10.0),
),
正文(
发布日期,
样式:TextStyle(
字体大小:18.0,
),
),
],
),
容器(仅限边缘集(顶部:8.0,底部:8.0)),
文本(说明),
容器(仅限边缘集(顶部:8.0,底部:8.0)),
正文(
“预告片”,
样式:TextStyle(
字体大小:25.0,
fontWeight:fontWeight.bold,
),
),
容器(仅限边缘集(顶部:8.0,底部:8.0)),
StreamBuilder(
流:集团,电影人,
建设者:
(上下文,异步快照){
if(snapshot.hasData){
回归未来建设者(
未来:snapshot.data,
建设者:
(上下文,异步快照项快照){
if(itemSnapShot.hasData){
如果(itemSnapShot.data.results.length>0)
返回trailerLayout(itemsnashot.data);
其他的
返回noTrailer(itemSnapShot.data);
}否则{
返回循环ProgressIndicator();
}
},
);
}否则{
返回循环ProgressIndicator();
}
},
),
],
),
),
),
);
}
小部件noTrailer(TrailerModel数据){
返回中心(
子:容器(
子项:文本(“无可用预告片”),
),
);
}
}
小部件trailerLayout(TrailerModel数据){
返回行(
奇尔德雷
dispose() async {
_movieId.close();
await _trailers.drain();
_trailers.close();
}
MovieDetailBloc() {
_movieId.stream.transform(_itemTransformer()).pipe(_trailers);
}
MovieDetailBloc() {
_movieId.stream.transform(_itemTransformer()).listen((data) {
if (!_categories.isClosed) {
_trailers.add(data);
}
});
}