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Exercise: Listening to events
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Did you remember to call listen() on the stream? | |
Did you call to processValue inside listen()? |
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import 'dart:async'; | |
void listenToStream(Stream<String> stream) { | |
// implement this method | |
} |
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void listenToStream(Stream<String> stream) { | |
stream.listen((event) => processValue(event)); | |
} |
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var processWasCalled = false; | |
void processValue(String value) { | |
print(value); | |
processWasCalled = value == "event"; | |
} | |
void main() { | |
// ignore: close_sinks | |
final controller = StreamController<String>(sync: true); | |
final stream = controller.stream; | |
listenToStream(stream); | |
// Check if student used `listen` | |
if (!controller.hasListener) { | |
_result(false, ['Something went wrong! Stream has no listeners. Did you call to `stream.listen()`?']); | |
return; | |
} | |
controller.add("event"); | |
// Check if student called to processValue inside listen | |
if (processWasCalled) { | |
_result(true); | |
} else { | |
_result(false, ['Something whent wrong! `processValue()` was not called when emitting a value']); | |
} | |
} |
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