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June 17, 2025 16:07
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Dart tip of the day / Lecture 20 / Stream
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import 'dart:async'; | |
import 'dart:math'; | |
import 'package:flutter/material.dart'; | |
void main() async { | |
// var firstUser = await getUserName(); | |
// var secondUser = await getUserName(); | |
// var thirdUser = await getUserName(); | |
print('헬로우 월드'); | |
// await for (var user in getUserNameStream()) { | |
// print('user : $user'); | |
// } | |
// print('헬로우 월드 2'); | |
var userNameStream = | |
getUserNameStream() | |
.asyncMap((username) { | |
return '$username is awesome!'; | |
}) | |
.distinct() | |
.asBroadcastStream(); | |
StreamSubscription<String>? subscription; | |
subscription = userNameStream.listen( | |
(user) { | |
print('user : $user'); | |
if (user == 'Bob') { | |
subscription?.cancel(); | |
} | |
}, | |
onDone: () { | |
print('onDone'); | |
}, | |
); | |
// userNameStream.listen( | |
// (user) { | |
// print('user : $user'); | |
// | |
// if (user == 'Bob') { | |
// subscription?.cancel(); | |
// } | |
// }, | |
// onDone: () { | |
// print('onDone'); | |
// }, | |
// ); | |
} | |
Stream<String> getUserNameStream() async* { | |
List<String> names = ["John", "Jane", "Bob", "Alice", "Tom"]; | |
await Future.delayed(const Duration(seconds: 1)); | |
yield "Bob"; | |
await Future.delayed(const Duration(seconds: 3)); | |
yield "Bob"; | |
await Future.delayed(const Duration(seconds: 2)); | |
yield names[Random().nextInt(names.length)]; | |
} | |
Future<String> getUserName() async { | |
List<String> names = ["John", "Jane", "Bob", "Alice", "Tom"]; | |
await Future.delayed(const Duration(seconds: 1)); | |
return names[Random().nextInt(names.length)]; | |
} |
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