ios - FirebaseDatabase - removeAllObservers() - 它实际上删除了什么？

Question

removeAllObservers() 是否仅删除其调用的 DatabaseReference 实例的所有观察者，或指定路径上的任何引用？

例如:

MainController.swift

let ref = Database.(...).child("foo/bar").observe(.value, with: handler)



ItemController.swift

public var ref2: DatabaseReference?

public func someMethod() {
    self.ref2 = Database.(...).child("foo/bar").observe(.value, with: handler2)
}

override func viewDidDisappear() {
    self.ref2?.removeAllObservers()
}

来自 MainController 的 ref 是否仍会观察 foo/bar 路径，或者该观察者也将被删除？

Answer 1

根据documentation :

If multiple listeners have been added to a database reference, each listener is called when an event is raised. In order to stop syncing data at that location, you must remove all observers at a location by calling the removeAllObservers method.

Calling removeObserverWithHandle or removeAllObservers on a listener does not automatically remove listeners registered on its child nodes; you must also keep track of those references or handles to remove them.

因此，换句话说，您需要将它们全部删除，它们不会自动删除，并且 MainController 中的 ref 仍然会观察到。