为什么EAAccessoryDidConnectNotification会发生两次？ [英] Why does EAAccessoryDidConnectNotification occur twice?

问题描述

我有一个班级来管理来自和转到iPad的外部附件的消息。在init中我有以下代码：

I have a class that manages messages coming from and going to an external accessory to an iPad. In the init I have the following code:

- (id) init
{
    self = [super init];
    if (!self) return;

    [[EAAccessoryManager sharedAccessoryManager] registerForLocalNotifications];    //we want to hear about accessories connecting and disconnecting
    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(accessoryDidConnect:)
                                                 name:EAAccessoryDidConnectNotification
                                               object:nil];

    [[NSNotificationCenter defaultCenter] addObserver:self
                                             selector:@selector(accessoryDidDisconnect:)
                                                 name:EAAccessoryDidDisconnectNotification
                                               object:nil];
    ...
}

在dealloc我有

- (void) dealloc
{
    [[NSNotificationCenter defaultCenter] removeObserver:self name:EAAccessoryDidDisconnectNotification object:nil];
    [[NSNotificationCenter defaultCenter] removeObserver:self name:EAAccessoryDidConnectNotification object:nil];
    [[EAAccessoryManager sharedAccessoryManager] unregisterForLocalNotifications];    
}

出于某种原因，当我将外部配件连接到iPad时，accessoryDidConnect：火灾后跟一个accessoryDidDisconnect：然后是accessoryDidConnect：

For some reason, when I connect the external accessory to the iPad the accessoryDidConnect: fires followed by an accessoryDidDisconnect: followed by accessoryDidConnect:

我无法弄清楚为什么我会得到额外的连接和断开连接。任何想法？

I can't figure out why I would get an extra connect and disconnect. Any ideas?

推荐答案

eaaccessory框架将始终从某种原因触发2个连接和2个断开连接通知。第一个连接断开线对没有协议字符串，你可以忽略它们。

the eaaccessory framework will always fire 2 connect and 2 disconnect notifications from some reason. The first connect disconnect pair will have no protocol strings, you can ignore these.

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