Simple UIButton Category to Support Event Blocks

UIButton+EventBlocks.h

// The MIT License (MIT)

// Copyright (c) 2014 Jan Cássio

// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#import <UIKit/UIKit.h>

typedef void (^UIEventBlock)(id sender, UIEvent *event);

@interface UIButton (EventBlocks)

@property (nonatomic, copy) UIEventBlock onTouchUpInside;

@end

UIButton+EventBlocks.m

// The MIT License (MIT)

// Copyright (c) 2014 Jan Cássio

// Permission is hereby granted, free of charge, to any person obtaining a copy
// of this software and associated documentation files (the "Software"), to deal
// in the Software without restriction, including without limitation the rights
// to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
// copies of the Software, and to permit persons to whom the Software is
// furnished to do so, subject to the following conditions:

// The above copyright notice and this permission notice shall be included in
// all copies or substantial portions of the Software.

// THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
// IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
// FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
// AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
// LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
// OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
// THE SOFTWARE.

#import "UIButton+EventBlocks.h"
#import <objc/runtime.h>

@interface UIButton (_EventBlocks_)

- (void)button:(UIButton *)button touchUpInsideWithEvent:(UIEvent *)event;

@end

@implementation UIButton (EventBlocks)

@dynamic onTouchUpInside;

static void *onTouchUpInsideKey = &onTouchUpInsideKey;

- (void)setOnTouchUpInside:(UIEventBlock)onTouchUpInside
{
  if(onTouchUpInside)
  {
    objc_setAssociatedObject(self, onTouchUpInsideKey, onTouchUpInside, OBJC_ASSOCIATION_COPY_NONATOMIC);
    [self addTarget:self action:@selector(button:touchUpInsideWithEvent:) forControlEvents:UIControlEventTouchUpInside];
  }
  else
  {
    objc_setAssociatedObject(self, onTouchUpInsideKey, nil, OBJC_ASSOCIATION_COPY_NONATOMIC);
    [self removeTarget:self action:@selector(button:touchUpInsideWithEvent:) forControlEvents:UIControlEventTouchUpInside];
  }
}

- (UIEventBlock)onTouchUpInside
{
  return objc_getAssociatedObject(self, onTouchUpInsideKey);
}

- (void)button:(UIButton *)button touchUpInsideWithEvent:(UIEvent *)event
{
  self.onTouchUpInside(button, event);
}

@end

UIButton+EventBlocks.md

#UIButton+EventBlocks

It's a simple category to implement event handler based in blocks.

Usage

1. Import UIButton+EventBlocks.h in your class

#import "UIButton+EventBlocks.h"

2. At any button instance of your class, you can handle UIControlEventTouchUpInside like this:

button.onTouchUpInside = ^(UIButton *button, UIEvent *event)
{
	// do something...
}

Also you can unlisten events if you pass nil as value for onTouchUpInside

button.onTouchUpInside = nil;

It's a very simple implementation for UIControlEventTouchUpInside, you can add blocks for any events you want, for example to add a handler block for UIControlEventTouchDown event, follow the steps:

1. Add a new property to category to access the block, onTouchDown is a good name for this

@property (nonatomic, copy) UIEventBlock onTouchDown;

2. Mark this call as @dynamic, without this, is impossible to bind the block

@dynamic onTouchDown;

3. Add a target handler in (EventBlocks) internal category

@interface UIButton (_EventBlocks_)

- (void)button:(UIButton *)button touchUpInsideWithEvent:(UIEvent *)event;
- (void)button:(UIButton *)button touchDownWithEvent:(UIEvent *)event;

@end

4. Add a pointer to set/get the reference for block

static void *onTouchDownKey = &onTouchDownKey;

5. Implement the setter method for onTouchDown property:

- (void)setOnTouchDown:(UIEventBlock)onTouchDown
{
  // If you pass nil
  if(onTouchDown)
  {
    objc_setAssociatedObject(self, onTouchDownKey, onTouchDown, OBJC_ASSOCIATION_COPY_NONATOMIC);
    [self addTarget:self action:@selector(button:touchDownWithEvent:) forControlEvents:UIControlEventTouchDown];
  }
  else
  {
    objc_setAssociatedObject(self, onTouchDownKey, nil, OBJC_ASSOCIATION_COPY_NONATOMIC);
    [self removeTarget:self action:@selector(button:touchDownWithEvent:) forControlEvents:UIControlEventTouchDown];
  }
}

6. Implement the getter method for onTouchDown property:

- (UIEventBlock)onTouchDown
{
  return objc_getAssociatedObject(self, onTouchDownKey);
}

7. Implement the target handler for UIControlEventTouchDown:

- (void)button:(UIButton *)button touchDownWithEvent:(UIEvent *)event
{
  self.onTouchDown(button, event);
}

Yes there is many steps to implement more callbacks but this will be handy in your day and this category is flexible enough for any project.