Amplify DataStore:如何知道何时完成同步?

Question

我们如何知道DataStore已经完成同步?

当用户登录后做第一个await DataStore.query(MyEntity)时，DataStore立即返回，而不是等待数据与云同步。

我想等待同步完成，并在数据尚未同步时加载。

Answer 1

您可以使用Amplify.Hub.listen.侦听数据存储通道上的事件

细节:

subscription = Amplify.Hub.listen([HubChannel.DataStore], (dynamic hubEvent) async {
switch (hubEvent.eventName) {
case 'networkStatus':
_amplifyIsUp.value = hubEvent.payload.active;
break;
case 'subscriptionsEstablished':
_amplifyMessage.value = 'Starting to sync from cloud...';
break;
case 'syncQueriesStarted':
_amplifyIsSyncing.value = true;
_amplifyMessage.value = 'Syncing...';
break;
case 'modelSynced':
ModelSyncedEvent mse = hubEvent.payload;
_amplifyMessage.value = '${mse.modelName} has been sync'd from cloud...';
break;
case 'syncQueriesReady':
_amplifyMessage.value = 'Done!';
_amplifyIsSyncing.value = false;

///do your bits here
onSyncsReady.call();

break;
case 'ready':
_amplifyIsSyncing.value = false;
break;
case 'subscriptionDataProcessed':

SubscriptionDataProcessedEvent sdpe = hubEvent.payload;
_amplifyMessage.value = 'Syncing ${sdpe.element.model.classType.modelName()}...';
if (sdpe.element.model is DeviceStatus) {
DeviceStatus ds = sdpe.element.model as DeviceStatus;
if (ds.clientID == _clientService.client.id && ds.status == Status.REQUESTSTATUS) {
_statusService.performHeartbeat();
} 
}
break;
case 'outboxMutationEnqueued':
_amplifyIsSyncing.value = true;
_amplifyHasDirt.value = true;
break;
case 'outboxMutationProcessed':
OutboxMutationEvent ome = hubEvent.payload;
_amplifyIsSyncing.value = false;
break;
case 'outboxStatus':
OutboxStatusEvent ose = hubEvent.payload;
if (ose.isEmpty) {
_amplifyIsSyncing.value = false;
_amplifyHasDirt.value = false;
} else {
_amplifyHasDirt.value = true;
}
break;
}
});

(boop)

Answer 2

让你的模型类成为可观察的，这样它就可以实时检查数据

Amplify.DataStore.observeQuery(MyEntity.classType).listen((event) {
if (event.isSynced) {//boolean value
print("Synced Successfully!");
// even you can get synced data here also
List< MyEntity> items = event.items;
} else {
//Show ProgressBar Here
print("Fetching Data From Cloud");
}
});