UIKeyCommand with modifier won't be recognized on first invocation

Question

I support keyboard shortcuts in my iOS app through serving UIKeyCommand instances from my view controller.

The following works like a charm and causes the provided selector to be invoked every time you press e:

- (BOOL)canBecomeFirstResponder {
    return YES;
}

- (NSArray *)keyCommands {
    return @[
        [UIKeyCommand keyCommandWithInput:@"e" modifierFlags:0 action:@selector(foo:)]];
    ];
}

However, I want the key command to be ⌘+e, or

[UIKeyCommand keyCommandWithInput:@"e" modifierFlags:UIKeyModifierCommand action:@selector(foo:)]

This still works, kind of. It won't work the first time you press ⌘+e, but it will work like a charm after that. Why does that happen and how can I fix it?

Aaron Brager · Accepted Answer · 2015-03-03T23:32:07.383

This is a known bug. As a workaround, you can register to respond to just the Command key by passing in an empty string and a selector that does nothing:

[UIKeyCommand keyCommandWithInput:@""
                    modifierFlags:UIKeyModifierCommand 
                           action:@selector(doNothing:)]

Then, by the time the user hits ⌘+e, it'll be the second invocation and it'll register fine.

More information on the bug can found here on OpenRadar. It was submitted on January 27, 2015, and marked as a duplicate on February 24.

UIKeyCommand with modifier won't be recognized on first invocation

1 Answers1