IOS Block的回调

//  Student.h

#import <Foundation/Foundation.h>

@interface Student : NSObject
- (void)PlayBeforeExam:(void(^)(NSString*))TakingMakeUpExam Punish:(void(^)(void))CompletionHandler;
@end

//  Student.m

#import "Student.h"

@implementation Student
- (void)PlayBeforeExam:(void (^)(NSString *))TakingMakeUpExam Punish:(void(^)(void))CompletionHandler{
    NSLog(@"play with my girlfriend!");
    NSLog(@"one month later...");
    /*方法执行完毕之后在某个时机调用block*/
    TakingMakeUpExam(@"english");
    CompletionHandler();
}
@end

- (void)viewDidLoad {
    [super viewDidLoad];
    
    Student *Zhangsan = [Student new];
    [Zhangsan PlayBeforeExam:^(NSString *English) {
        NSLog(@"Zhangsan is taking %@ make-up exam, but failed again!",English);
    }Punish:^{
        NSLog(@"Break Up!");
    }];
    
}

2016-04-21 00:33:31.335 callback[1520:131334] play with my girlfriend!
2016-04-21 00:33:31.350 callback[1520:131334] one month later...
2016-04-21 00:33:31.350 callback[1520:131334] Zhangsan is taking english make-up exam, but failed again!
2016-04-21 00:33:31.350 callback[1520:131334] Break Up!