How to reliably detect if an external keyboard is connected on iOS 9?

Question

Previous to iOS 9, the most reliable method of determining whether an external keyboard is connected was to listen for UIKeyboardWillShowNotification and make a

Answer 1

You can subscribe notification when the external device is connected:

[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(deviceConnected:) name:EAAccessoryDidConnectNotification object:nil];
[[NSNotificationCenter defaultCenter] addObserver:self selector:@selector(deviceDisconnected:) name:EAAccessoryDidDisconnectNotification object:nil];
[[EAAccessoryManager sharedAccessoryManager] registerForLocalNotifications];

Or just retrieve the list of attached devices:

EAAccessoryManager* accessoryManager = [EAAccessoryManager sharedAccessoryManager];

if (accessoryManager)
{
    NSArray* connectedAccessories = [accessoryManager connectedAccessories];
    NSLog(@"ConnectedAccessories = %@", connectedAccessories);
}