代理

第一步：
@protocol SDCycleScrollViewDelegate <NSObject>
//@optional
/** 点击图片回调 */
- (void)cycleScrollView:(SDCycleScrollView *)cycleScrollView didSelectItemAtIndex:(NSInteger)index;

@end


第二步:
@property (nonatomic, weak) id<SDCycleScrollViewDelegate> delegate;

第三步：
if ([self.delegate respondsToSelector:@selector(cycleScrollView:didSelectItemAtIndex:)]) {
  [self.delegate cycleScrollView:self didSelectItemAtIndex:indexPath.item % self.imagePathsGroup.count];
    }

第四步：
<SDCycleScrollViewDelegate>

第五步：
_bannerView.delegate = self;

第六步：
- (void)cycleScrollView:(SDCycleScrollView *)cycleScrollView didSelectItemAtIndex:(NSInteger)index{
//执行相应的方法
}

block

第一步：
@class LYUser;
typedef void (^LoginSuccessBlock)(LYUser *);

第二步：
/* 登录成功之后的回调闭包 */
@property (nonatomic, copy) LoginSuccessBlock block;

第三步：
if(self.block) {
   self.block(user);
 }

第四步：
LYLoginViewController *loginVc = [[LYLoginViewController alloc] init];
loginVc.block = ^(LYUser *user) {
    UIImage *image = [UIImage imageWithData:[NSData dataWithContentsOfURL:[NSURL URLWithString:user.avatar_url]]];
    [weakSelf.headerView.iconButton setBackgroundImage:image forState:UIControlStateNormal];
    weakSelf.headerView.nameLabel.text = user.nickname;
           
  // 保存登录状态
 [[NSUserDefaults standardUserDefaults] setBool:YES forKey:@"isLogin"];
 [[NSUserDefaults standardUserDefaults] setObject:user.avatar_url forKey:@"avatar_url"];
 [[NSUserDefaults standardUserDefaults] setObject:user.nickname forKey:@"nickname"];
 [[NSUserDefaults standardUserDefaults] synchronize];
// 登录成功重新请求数据以及刷新视图
  [weakSelf loadLikeLoad];
  [weakSelf inspectStatus];
  };
        
MRNavigationController *loginNav = [[MRNavigationController alloc] initWithRootViewController:loginVc];
[self.navigationController presentViewController:loginNav animated:YES completion:nil];
 }

block2

第一步：
/** block方式监听点击 */
@property (nonatomic, copy) void (^clickItemOperationBlock)(NSInteger currentIndex);

第二步：
   if (self.clickItemOperationBlock) {
   self.clickItemOperationBlock(indexPath.item % self.imagePathsGroup.count);
    }

第三步 ：
ViewController2 *vc =[[ViewController2 alloc]init];
    // 回调修改颜色
    vc.clickItemOperationBlock = ^(NSInteger currentIndex){
        //执行相应的方法
    };

block3

@property (nonatomic, copy) void(^sureAndGetCodeActionBlock)(UIButton *sender);

 if (self.sureAndGetCodeActionBlock) {
        self.sureAndGetCodeActionBlock(sender);
    }

 self.bindView.sureAndGetCodeActionBlock = ^(UIButton *sender) {
   
    }