UIButton block equivalent to addTarget:action:forControlEvents: method?

Question

I looked around, but couldn\'t find this on the internet, nor anywhere in the Apple docs, so I\'m guessing it doesn\'t exist.

But is there a iOS4 blocks equivalent A

Answer 1

I find it easy and versatile to use a tiny helper class:

@interface Handler : NSObject

@end

@implementation Handler {
    void (^block)(id);
}

+ (Handler *)create:(void (^)(id))block {
    Handler *result = [[Handler alloc] init];

    result->block = block;

    return result;
}

- (void)call:(id)sender {
    block(sender);
}

@end

and use it like this:

Handler *handler = [Handler create:^(id sender) {
    // ... handle the event, using local state captured by the block ...
}];

// store the handler because the target is not retained in addTarget
[handlers addObject:handler];

[button addTarget:handler action:@selector(call:) forControlEvents:UIControlEventTouchUpInside];