ios - NSOperationQueue 什么时候从队列中删除一个操作？

Question

我需要知道 NSOperationQueue 何时从队列中删除操作？我有 NSOperationQueue，其中包含 NSOperation 列表。 NSOperationQueue 何时从队列中删除操作？

1. 开始手术后？或者
2. 完成/取消操作后？

因为当 NSOPerationqueue 中的所有操作完成时我需要通知。为此，我提到了 this link

Answer 1

根据苹果开发者引用

An operation queue executes its queued NSOperation objects based on their priority and readiness. After being added to an operation queue, an operation remains in its queue until it reports that it is finished with its task.

因此，NSOperationQueue 在操作完成后将其删除。

来源 - https://developer.apple.com/library/mac/documentation/Cocoa/Reference/NSOperationQueue_class/Reference/Reference.html