-(void)click:(UIButton *)sender
{NSString *message = @"你是谁";UIAlertView *alert = [[UIAlertView alloc]initWithTitle:@"提示" message:@"我要传值·" delegate:self cancelButtonTitle:@"确定" otherButtonTitles:nil];alert.delegate = self;[alert show];//#import <objc/runtime.h>头文件//objc_setAssociatedObject需要四个参数：源对象，关键字，关联的对象和一个关联策略。//1 源对象alert//2 关键字 唯一静态变量key associatedkey//3 关联的对象 sender//4 关键策略  OBJC_ASSOCIATION_ASSIGN
//    enum {
//        OBJC_ASSOCIATION_ASSIGN = 0,           若引用/**< Specifies a weak reference to the associated object. */
//        OBJC_ASSOCIATION_RETAIN_NONATOMIC = 1, /**< Specifies a strong reference to the associated object.
//                                                *   The association is not made atomically. */
//        OBJC_ASSOCIATION_COPY_NONATOMIC = 3,   /**< Specifies that the associated object is copied.
//                                                *   The association is not made atomically. */
//        OBJC_ASSOCIATION_RETAIN = 01401,       /**< Specifies a strong reference to the associated object.
//                                                *   The association is made atomically. */
//        OBJC_ASSOCIATION_COPY = 01403          /**< Specifies that the associated object is copied.
//                                                *   The association is made atomically. */
//    };objc_setAssociatedObject(alert, @"msgstr", message,OBJC_ASSOCIATION_ASSIGN);//把alert和message字符串关联起来，作为alertview的一部分，关键词就是msgstr，之后可以使用objc_getAssociatedObject从alertview中获取到所关联的对象，便可以访问message或者btn了//    即实现了关联传值objc_setAssociatedObject(alert, @"btn property",sender,OBJC_ASSOCIATION_ASSIGN);
}
-(void)alertView:(UIAlertView *)alertView clickedButtonAtIndex:(NSInteger)buttonIndex
{//通过 objc_getAssociatedObject获取关联对象NSString  *messageString =objc_getAssociatedObject(alertView, @"msgstr");UIButton *sender = objc_getAssociatedObject(alertView, @"btn property");NSLog(@"%ld",buttonIndex);NSLog(@"%@",messageString);NSLog(@"%@",[[sender titleLabel] text]);//使用函数objc_removeAssociatedObjects可以断开所有关联。通常情况下不建议使用这个函数，因为他会断开所有关联。只有在需要把对象恢复到“原始状态”的时候才会使用这个函数。
}