用block改写UIButton点击事件,block改写UIAlerView的代理

大致就是自定义一个BlockButton继承UIButton，然后在里面用

addTarget:(id)target action:(SEL)action forControlEvents:(UIControlEvents)controlEvents

这个方法触发block，代码很简单，不多说了

BlockButton.h

@class BlockButton;
typedef void (^TouchButton)(BlockButton*);

@interface BlockButton : UIButton

@property(nonatomic,copy)TouchButton block;

@end

BlockButton.m

#import "BlockButton.h"
#import <QuartzCore/QuartzCore.h>//这里要注意，如果想使用UIButton的layer属性更改button样式，要添加QuartzCore.framewor并且在头文件导入。

@implementation BlockButton

- (id)initWithFrame:(CGRect)frame
{
    self = [super initWithFrame:frame];
    if (self) {
        self.layer.masksToBounds = YES;
        self.layer.cornerRadius = 10;
        self.layer.borderWidth = 2;
        self.layer.shadowRadius = 2;
        self.layer.shadowColor = [UIColor grayColor].CGColor;
        self.layer.borderColor = [UIColor redColor].CGColor;
        [self addTarget:self action:@selector(touchAction:) forControlEvents:UIControlEventTouchUpInside];
        
    }
    return self;
}

- (void)touchAction:(id)sender{
    _block(self);
}

@end

ViewController.h里面没有添加任何代码

下面是ViewController.m

#import "ViewController.h"
#import "BlockButton.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    self.view.backgroundColor = [UIColor whiteColor];
    BlockButton *button = [[BlockButton alloc]initWithFrame:CGRectMake(100, 100, 40, 20)];
    [button setBlock:^(BlockButton *button){
        NSLog(@"按下去了");
    }];
    [self.view addSubview:button];
    [button release];
    
    for (int i = 0; i < 3; i ++) {
        BlockButton *btn = [[BlockButton alloc]initWithFrame:CGRectMake(40 + i*70, 200, 50, 25)];
        [btn setTitle:[NSString stringWithFormat:@"%d",i] forState:UIControlStateNormal];
        [btn setTitleColor:[UIColor blackColor] forState:UIControlStateNormal];
        btn.block = ^(BlockButton *btn){
             NSLog(@"按下%d",i);
        };
        [self.view addSubview:btn];
        [btn release];
    }
}


@end

下面再改写Alert这个控件，思路是一样的，在自定义的Alert里面用block触发点击事件，而在Alert定义的代码里执行事件触发的行为。
AlertBlock.h

#import <UIKit/UIKit.h>

@class AlertBlock;
typedef void (^TouchBlock)(NSInteger);
@interface AlertBlock : UIAlertView

@property(nonatomic,copy)TouchBlock block;
//需要自定义初始化方法，调用Block
- (id)initWithTitle:(NSString *)title
            message:(NSString *)message
  cancelButtonTitle:(NSString *)cancelButtonTitle
  otherButtonTitles:(NSString*)otherButtonTitles
              block:(TouchBlock)block;
@end

AlertBlock.m

#import "AlertBlock.h"

@implementation AlertBlock

- (id)initWithTitle:(NSString *)title message:(NSString *)message cancelButtonTitle:(NSString *)cancelButtonTitle otherButtonTitles:(NSString*)otherButtonTitles block:(TouchBlock)block{
    self = [super initWithTitle:title message:message delegate:self cancelButtonTitle:cancelButtonTitle otherButtonTitles:otherButtonTitles, nil];//注意这里初始化父类的
    if (self) {
        self.block = block;
    }
    return self;
}

//#pragma mark -AlertViewDelegate
- (void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex{
//这里调用函数指针_block(要传进来的参数);
    _block(buttonIndex);
}

@end

ViewController.m

#import "ViewController.h"
#import "AlertBlock.h"

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad
{
    [super viewDidLoad];
    UIButton *button = [UIButton buttonWithType:UIButtonTypeRoundedRect];
    [button addTarget:self action:@selector(buttonAction:) forControlEvents:UIControlEventTouchUpInside];
    button.frame = CGRectMake(self.view.bounds.size.width/2, self.view.bounds.size.height/2, 80, 30);
    [self.view addSubview:button];
}

- (void)buttonAction:(id)sender{
    AlertBlock *alert = [[AlertBlock alloc]initWithTitle:@"提示" message:nil cancelButtonTitle:@"取消" otherButtonTitles:@"确定" block:^(NSInteger buttonIndex){
//在这里面执行触发的行为，省掉了代理，这样的好处是在使用多个Alert的时候可以明确定义各自触发的行为，不需要在代理方法里判断是哪个Alert了
        if (buttonIndex == 0) {
            NSLog(@"取消");
        }else if (buttonIndex == 1){
            NSLog(@"确定");
        }
    }];
    [alert show];
    [alert release];
}