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stream_builder_demo.dart
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stream_builder_demo.dart
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import 'package:flutter/material.dart';
import 'package:pro_flutter/demo/stream_demo/stream_demo_event.dart';
import 'package:pro_flutter/demo/stream_demo/stream_demo_model.dart';
import 'package:pro_flutter/demo/stream_demo/stream_demo_state.dart';
class StreamBuilderDemo extends StatefulWidget {
@override
_StreamBuilderDemoState createState() => _StreamBuilderDemoState();
}
class _StreamBuilderDemoState extends State<StreamBuilderDemo> {
final model = StreamDemoModel();
@override
void initState() {
model.dispatch(FetchData(hasData: true));
super.initState();
}
@override
Widget build(BuildContext context) {
return Scaffold(
appBar: AppBar(
title: Text('Stream Builder Demo'),
),
floatingActionButton: FloatingActionButton(
backgroundColor: Colors.yellow,
child: Icon(
Icons.cached,
color: Colors.black87,
),
onPressed: () {
model.dispatch(FetchData());
},
),
body: StreamBuilder(
stream: model.streamState,
builder: (buildContext, snapshot) {
if (snapshot.hasError) {
return _getInformationMessage(snapshot.error);
}
var streamState = snapshot.data;
if (!snapshot.hasData || streamState is BusyState) {
return Center(
child: CircularProgressIndicator(
valueColor: AlwaysStoppedAnimation<Color>(Colors.yellow),
backgroundColor: Colors.yellow[100],
),
);
}
if (streamState is DataFetchedState) {
if (!streamState.hasData) {
return _getInformationMessage('not found data');
}
}
return ListView.builder(
itemCount: streamState.data.length,
itemBuilder: (buildContext, index) =>
_getListItem(index, streamState.data),
);
},
),
);
}
Widget _getListItem(int index, List<String> listItems) {
return Column(
children: <Widget>[
ListTile(
title: Text(listItems[index]),
),
Divider(),
],
);
}
Widget _getInformationMessage(String message) {
return Center(
child: Text(
message,
style: TextStyle(
fontSize: 16.0,
fontWeight: FontWeight.w900,
color: Colors.grey[500]),
textAlign: TextAlign.center,
),
);
}
}