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

There is a library of blocks additions to the common Foundation/UI classes: BlocksKit. Here is the documentation.

It does not subclass UIButton, but adds UIControl category:

[button addEventHandler:^(id sender) {
    //do something
} forControlEvents:UIControlEventTouchUpInside];

There is also blocks/functional additions to collections (map, filter, etc), views-related stuff and more.

NOTE: it does not play well with Swift.

Answer 2

I just implemented this. It work's like a charm!

And it wasn't even hard.

typedef void (^ActionBlock)();

@interface UIBlockButton : UIButton {
    ActionBlock _actionBlock;
}

-(void) handleControlEvent:(UIControlEvents)event
                 withBlock:(ActionBlock) action;
@end

@implementation UIBlockButton

-(void) handleControlEvent:(UIControlEvents)event
                 withBlock:(ActionBlock) action
{
    _actionBlock = action;
    [self addTarget:self action:@selector(callActionBlock:) forControlEvents:event];
}

-(void) callActionBlock:(id)sender{
    _actionBlock();
}
@end

Answer 3

There is REKit which brings out Blocks latent ability. It gives you ability to add/override method to a instance using Block.

With REKit, you can dynamically make a target - which responds to buttonAction - like below:

id target;
target = [[NSObject alloc] init];
[target respondsToSelector:@selector(buttonAction) withKey:nil usingBlock:^(id receiver) {
    // Do something…
}];
[button addTarget:target action:@selector(buttonAction) forControlEvents:UIControlEventTouchUpInside];

You don't need to make a subclass nor a category.

In addition to target/action paradigm, you can use REKit for delegation pattern.