How to tell programmatically if a IBAction has been called by code or by user action

Question

How can I tell programmatically if a IBAction has been called by code or by user action.

Eg I have a method, -(IBAction)someMethodWithIts:(id)sender which I have linked to a valueChanged on a UISegmentedControl.

It can be called by,

User changing segment
setting the selectedIndex in code
calling [self someMethodWithIts:foo];

Is there a way to distinguish if the call has come from the first way?

Cheers

Sam

An instance of what? You can use that information to distinguish. — BoltClock, Aug 23 '11 at 01:46
From 1 or 2 the sender will be a pointer to the control. From 3 it's whatever foo is. — progrmr, Aug 23 '11 at 01:53

Rob Napier · Accepted Answer · 2011-08-23T15:18:11.077

If you can pass nil as the sender (which is traditional) and use that to indicate it was sent programmatically, that's ok. But anything else I believe is too fragile and you should break up the code like this:

- (void)someMethod {
  // stuff shared by everyone
}

- (IBAction)someMethodWithIts:(id)sender {
  // stuff specific to IBAction
  [self someMethod];
}

If you really want a sender, then you can do it this way:

- (void)someMethodWithIts:(id)sender triggeredByUser:(BOOL)isUser {
}

- (IBAction)someMethodWithIts:(id)sender {
  [self someMethodWithIts:sender triggeredByUser:YES];
}

But in general, if you want the IBAction to be different than programatic changes, then don't wire programatic changes to the IBAction.

score 0 · Answer 2 · answered Aug 23 '11 at 05:31

if ([sender isKindOfClass:[UIControl class]]) {
    UIControl *controlSender = (UIControl *)sender;
    if (sender.selected) {
        // then it's #1
    } else {
        // then it's #2
    }
} else if ([sender isKindOfClass:[Foo class]]) {
    // then it's #3
}

Might work. Or poke around other properties of sender defined on UIControl or UISegmentedControl. Maybe state. My guess is you can find something that's different when the user is interacting vs. when they're not.

score 0 · Answer 3 · answered Aug 23 '11 at 07:14

You really want to use method like this

-(IBAction)actionWithSender:(id)sender event:(UIEvent*)event
{
    if (event) {

    } else {

    }
}

If you find the event parameter is nil, it's from a call in your code, otherwise, the call is from user event.

How to tell programmatically if a IBAction has been called by code or by user action

3 Answers3