block 和delegate的用法

//block 和delegate的用法 设置代理
#import <UIKit/UIKit.h>

typedef void (^ASIHeadersBlock)(NSString *myString);

@protocol AHViewControllerDelegate <NSObject>

- (void)smyheadersReceivedBlock:(NSString *)string;

@end

@interface AHViewController : UIViewController
{
    ASIHeadersBlock headersReceivedBlock;

    NSObject <AHViewControllerDelegate> *delegate;
}

@property (nonatomic, assign) NSObject <AHViewControllerDelegate> * delegate;

- (void)setHeadersReceivedBlock:(ASIHeadersBlock)aReceivedBlock;

@end

---------------------------------------------------------------------

//
//  AHViewController.m
//  TestBlock
//
//  Created by ganvin on 13-4-12.
//  Copyright (c) 2013年 ganvin. All rights reserved.
//

#import "AHViewController.h"

@interface AHViewController ()

@end

@implementation AHViewController
@synthesize  delegate;
- (void)setHeadersReceivedBlock:(ASIHeadersBlock)aReceivedBlock
{
[headersReceivedBlock release];
headersReceivedBlock = [aReceivedBlock copy];
}

- (void)viewDidLoad
{
    [super viewDidLoad];

// Do any additional setup after loading the view, typically from a nib.
if(headersReceivedBlock)
    {
     headersReceivedBlock(@"ssss");
  }

    if (delegate!= nil && [delegate respondsToSelector:@selector(smyheadersReceivedBlock:)])
    {
        [delegate performSelector:@selector(smyheadersReceivedBlock:) withObject:@"sssss"];
    }
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}
- (void)dealloc
{
    delegate = nil;
if (headersReceivedBlock)
    {
[headersReceivedBlock release];
headersReceivedBlock = nil;
}
    [super dealloc];
}
@end