我正在尝试从网络加载图像,并将其显示在GridView
中。我正在使用一个StatefulWidget
并在build
方法中加载图像。但是根据我的理解,在build
方法中进行网络调用是不好的。如何从网络下载BLoC
文件中的图像,然后将下载的图像列表传递给小部件?下面是我当前的实现。
class MovieList extends StatefulWidget {
@override
State<StatefulWidget> createState() {
return MovieListState();
}
}
class MovieListState extends State<MovieList> {
@override
void initState() {
super.initState();
bloc.fetchAllMovies();
}
@override
void dispose() {
bloc.dispose();
super.dispose();
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Popular Movies'),
),
body: StreamBuilder(
stream: bloc.allMovies,
builder: (context, AsyncSnapshot<ItemModel> snapshot) {
if (snapshot.hasData) {
return buildList(snapshot);
} else if (snapshot.hasError) {
return Text(snapshot.error.toString());
}
return Center(child: CircularProgressIndicator());
},
),
);
}
Widget buildList(AsyncSnapshot<ItemModel> snapshot) {
return GridView.builder(
itemCount: snapshot.data.results.length,
gridDelegate:
new SliverGridDelegateWithFixedCrossAxisCount(crossAxisCount: 2),
itemBuilder: (BuildContext context, int index) {
return GridTile(
child: InkResponse(
enableFeedback: true,
child: Image.network(
'https://image.tmdb.org/t/p/w185${snapshot.data
.results[index].poster_path}',
fit: BoxFit.cover,
),
onTap: () => openDetailPage(snapshot.data, index),
),
);
});
}
openDetailPage(ItemModel data, int index) {
Navigator.push(
context,
MaterialPageRoute(builder: (context) {
return MovieDetailBlocProvider(
child: MovieDetail(
title: data.results[index].title,
posterUrl: data.results[index].backdrop_path,
description: data.results[index].overview,
releaseDate: data.results[index].release_date,
voteAverage: data.results[index].vote_average.toString(),
movieId: data.results[index].id,
),
);
}),
);
}
}
最佳答案
我建议你用
https://pub.dartlang.org/packages/cached_network_image
这对我的案子很有用。
简单的代码示例
CachedNetworkImage(
imageUrl: "http://via.placeholder.com/350x150",
placeholder: CircularProgressIndicator(),
errorWidget: Icon(Icons.error),
),
或
Image(image: CachedNetworkImageProvider(url))
您应该添加到pubspec文件
cached_network_image: <actual version here>
进入依赖项部分
关于flutter - 从网络 flutter 中加载图像的更好方法,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/53577962/