Flutter apps terus-terusan nangani asynchronous operations (network requests, file access, database queries). Futures Dart (single async results) lan Streams (sequences of async events), karo async/await lan widgets kaya FutureBuilder/StreamBuilder, iku essential kanggo async UI.
// a Future represents a single async result that completes later
Future<String> fetchUser() async {
final response = await http.get(url); // await pauses until the Future completes
return response.body; // returns the result
}
// using it
final data = await fetchUser(); // await the result
// or: fetchUser().then((data) => ...); // callback style
Future = nilai tunggal kang ana mengko (network response, file read). async/await ndadekake async code maca kanthi sequential.
// FutureBuilder rebuilds the UI based on the Future's state (loading/data/error)
FutureBuilder<String>(
future: fetchUser(),
builder: (context, snapshot) {
if (snapshot.connectionState == ConnectionState.waiting) {
return CircularProgressIndicator(); // loading
} else if (snapshot.hasError) {
return Text('Error: ${snapshot.error}'); // error
} else {
return Text(snapshot.data!); // got the data
}
},
)
// a Stream = a SEQUENCE of async events over time (e.g. live data, websocket, sensor)
Stream<int> counter() async* {
for (int i = 0; i < 10; i++) {
await Future.delayed(Duration(seconds: 1));
yield i; // emit each value
}
}
// StreamBuilder rebuilds the UI as new events arrive
StreamBuilder<int>(stream: counter(), builder: (context, snapshot) => Text('${snapshot.data}'))
Ngerteni async, Futures, lan Streams iku essential amarga Flutter apps terus-terusan nangani asynchronous operations, dadi nangani iku karo bener iku fundamental kanggo ngbangun real apps.
Sakethene app nindakake async work — network requests, file access, database queries, real-time data — lan Dart's async primitives iku cara kanggo nangani iku.
Ngerteni Futures (mewakili single async result kang ana mengko, kaya network response) karo async/await (ndadekake async code maca kanthi sequential lan bersih) iku essential kanggo nindakake async operations.
Ngerteni FutureBuilder khususnya penting kanggo UI: iku ngubunake UI based on Future's state, nangani kanthi bener loading, error, lan data states — kang iku persis apa sing real apps butuh (nampilake spinner pas lagi loading, error message waktu failure, lan data pas success), pola umum lan essential kanggo async UI.
Ngerteni Streams (sequences saka async events liwat wektu, kaya live data, websockets, utawa sensor readings) lan StreamBuilder (rebuild UI nalika events anyar teka) iku essential kanggo reactive, real-time UIs lan kanggo state management approaches kang dibangun ing streams.
Nangani async kanthi bener — kaasil loading/error/data states kang FutureBuilder lan StreamBuilder manage — iku fundamental kanggo ngbangun apps kang fetch lan display data kanthi bener (inti saka paling apps).
Cara Flutter apps terus-terusan nindakake asynchronous operations (network, files, real-time data) lan nampilake hasilnya butuh nangani async states kanthi bener, lan cara Futures, Streams, async/await, lan Builder widgets iku essential tools kanggo iku, ngerteni async, Futures, lan Streams ing Flutter iku essential, frequently-applied knowledge — fundamental kanggo ngbangun apps kang nangani data lan async operations kanthi bener, core skill kang dibutuhake ing sakethene real Flutter application kang fetch utawa process data.