Events for custom UIView

Question

What's the best way for registering events for my UIView subclass, so that I can connect them to IBAction-s in interface builder?

Currently I've just got a standard UIView dropped onto my main view and I've set the class to "RadioDial" (my custom class). This displays the view fine, but I have no idea how to get events out of it.

Thanks

Answer 1

Create a method in your view controller (if nothing else, you should have a RootViewController in you project). Let's say your method is

  -(void) buttonClicked { code code code }

In the controller's header file (for example RootViewController.h) you then put:

  -(IBAction) buttonClicked;

And in IB you right-click your button/radio dial/whatever. You will see a list of events and you can drag FROM the connector of the event you want your controller to receive, to the object in IB that represents the controler (probably First Responder). This depends on how your IB structure is set up, but it should be straightforward.

Another alternative is to learn how to create UIViews programatically, and forget about IB for the time being. Opinions are divided about whether it's better to learn to use IB at the outset, or whether it's better to learn how to do everything in code and save IB for later. In any case, it's necessary to learn both ways of setting up an interface at some point.

Answer 2

Please clarify: do you mean that you would like Interface Builder to offer your view controllers to wire up custom events that your view subclass will be emitting (much like the Button controls allow you to wire up Touch Inside, etc)?

If you need this type of functionality, you will need to use a generalized 'delegate' property on your View combined with a protocol.

@protocol RadioDialDelegate
-(void)dialValueChanged:(id)sender
@end

@interface RadioDial
{
    id<RadioDialDelegate> radioDelegate;
}
@property (nonatomic, assign) IBOutlet id<RadioDialDelegate> radioDelegate;

This will allow the controller to wire up to the view (assuming it implements RadioDialDelegate) and receive any events that come out of the view. Alternatively, you can use an untyped delegate and in your View code, use a late bound call:

if([radioDelegate respondsToSelector:@selector(dialValueChanged:)]) {
    [radioDelegate dialValueChanged:self];
}