UIBarButtonItem: target-action not working?

I do not think the target and action of the UIBarButtonItem apply to custom views. Try using a UIButton instead of UIImageView and applying the target and action to the button.

Sample code in Swift:

let button  = UIButton(type: .Custom)
if let image = UIImage(named:"icon-menu.png") {
    button.setImage(image, forState: .Normal)
}
button.frame = CGRectMake(0.0, 0.0, 30.0, 30.0)
button.addTarget(self, action: #selector(MyClass.myMethod), forControlEvents: .TouchUpInside)
let barButton = UIBarButtonItem(customView: button)
navigationItem.leftBarButtonItem = barButton

I had the same problem, but was averse to using a UIButton instead of a custom view for my UIBarButtonItem (per drawnonward's response).

Alternatively, you could add a UIGestureRecognizer to the custom view before using it to initialize UIBarButtonItem; this appears to work in my project.

This is how I would modify your original code:

UIImageView *SOCImageView = [[UIImageView alloc] initWithImage:
                             [UIImage imageNamed:@"cancel_wide.png"]];

UITapGestureRecognizer *tapGesture = 
       [[UITapGestureRecognizer alloc] initWithTarget:self 
                                               action:@selector(deselectAll:)];
[SOCImageView addGestureRecognizer:tapGesture];

SOItem.leftBarButtonItem = 
       [[[UIBarButtonItem alloc] initWithCustomView:SOCImageView] autorelease];
[tapGesture release];
[SOCImageView release];