相关疑难解决方法(0)

添加观察者是否会增加对象的保留计数？如果是,ARC是否也会处理此观察者的移除？如果没有,我应该在哪里删除观察者？

当我注册一个对象foo以从另一个对象栏接收KVO通知时(使用addObserver:...),如果我然后解除分配foo,我是否需要在-dealloc中removeObserver:forKeyPath:向bar发送消息？

我看到了以下崩溃报告,但它不可重现.我该如何调试呢？这是AFNetworking问题吗？我正在使用2.4.1版.

Crashed: com.apple.NSURLSession-work
EXC_BAD_ACCESS KERN_INVALID_ADDRESS at 0x0000000000000000

Thread : Crashed: com.apple.NSURLSession-work
0  CoreFoundation                 0x0000000184aad978 CFDictionaryGetValue + 56
1  Foundation                     0x0000000185aa9300 _NSSetLongLongValueAndNotify + 72
2  Foundation                     0x0000000185aa9300 _NSSetLongLongValueAndNotify + 72
3  CFNetwork                      0x0000000184543468 -[__NSCFLocalSessionTask _task_onqueue_didFinish] + 472
4  CFNetwork                      0x0000000184544b38 -[__NSCFLocalSessionTask connection:didFinishLoadingWithError:] + 40
5  CFNetwork                      0x000000018458d030 __46-[__NSCFURLSessionConnection _task_sendFinish]_block_invoke + 136
6  libdispatch.dylib              0x0000000196a49994 _dispatch_call_block_and_release + 24
7  libdispatch.dylib              0x0000000196a49954 _dispatch_client_callout + 16
8  libdispatch.dylib              0x0000000196a540a4 _dispatch_queue_drain + 1448
9  libdispatch.dylib              0x0000000196a4ca5c _dispatch_queue_invoke + 132
10 libdispatch.dylib              0x0000000196a56318 _dispatch_root_queue_drain + 720 …