同期された Realm を開く - Flutter SDK

// Helper function to check if device is connected to the internet.
Future<bool> isDeviceOnline() async {
  // ...logic to check if device is online
}
final config = Configuration.flexibleSync(currentUser, [Tricycle.schema]);
// Only use asynchronous open if app is online.
late Realm realm;
if (await isDeviceOnline()) {
  // If the device is online, download changes and then open the realm.
  realm = await Realm.open(config);
} else {
  // If the device is offline, open the realm immediately
  // and automatically sync changes in the background when the device is online.
  realm = Realm(config);
}

double progressEstimate = -1;
final realm = await Realm.open(config, onProgressCallback: (syncProgress) {
  progressEstimate = syncProgress.progressEstimate;
  print('Sync progress: ${progressEstimate * 100}% complete.');
  if (progressEstimate == 1.0) {
    // Transfer is complete
  }
});

final token = CancellationToken();
// Cancel the open operation after 30 seconds.
// Alternatively, you could display a loading dialog and bind the cancellation
// to a button the user can click to stop the wait.
Future<void>.delayed(
    const Duration(seconds: 30),
    () => token.cancel(CancelledException(
        cancellationReason: "Realm took too long to open")));
// If realm does not open after 30 seconds with asynchronous Realm.open(),
// open realm immediately with Realm() and try to sync data in the background.
late Realm realm;
try {
  realm = await Realm.open(config, cancellationToken: token);
} on CancelledException catch (err) {
  print(err.cancellationReason); // prints "Realm took too long to open"
  realm = Realm(config);
}