在Flutter中停止收听Cloud Firestore中的快照更新

问题描述

我想停止收听快照更新.即使关闭屏幕，快照仍会继续监听更新.我正在使用以下代码来监听更新.

I want to stop listening to snapshot updates. The snapshot keeps listening to updates even after the screen is closed. I am using the below code to listen to the updates.

CollectionReference reference = Firestore.instance.collection('Events');
reference.snapshots().listen((querySnapshot) {
  querySnapshot.documentChanges.forEach((change) {
    // Do something with change
  });
})

推荐答案

您的侦听器类型为StreamSubscription，因此您可以在侦听器上调用一些有用的方法，例如cancel()

Your listener is of type StreamSubscription, so you can call some helpful methods on your listener such as cancel()

    CollectionReference reference = Firestore.instance.collection('Events');
StreamSubscription<QuerySnapshot> streamSub = reference.snapshots().listen((querySnapshot) {
  querySnapshot.documentChanges.forEach((change) {
    // Do something with change
  });
});
//somewhere
streamSub.cancel();

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