自定义块上的EXC_BAD_ACCESS

Question

我在一个类中定义了一个块:

BXButton.h

typedef void(^ButtonClicked)(id sender, NSDictionary *userInfo);
@property (assign, nonatomic) ButtonClicked onButtonClicked;
- (void)setClickBlock:(ButtonClicked)buttonClicked;

BXButton.m

- (void)setClickBlock:(ButtonClicked)buttonClicked {
    onButtonClicked = buttonClicked;
}
- (void)internalButtonClicked {
    DLog(@"internal clicked");
    if (self.onButtonClicked) {
        onButtonClicked(self, self.userInfo);
    }
}

我试图在视图控制器中这样调用:

[_testButton setClickBlock:^(BXButton *sender, NSDictionary *userInfo) {
        DLog(@"userInfo %@", userInfo);
        [sender startLoading];
        [[BXAPIClient sharedPublicClient]postPath:@"/" parameters:nil success:^(AFHTTPRequestOperation *operation, id responseObject) {
            [sender endLoading];
            //[safeSelf stop];
        } failure:^(AFHTTPRequestOperation *operation, NSError *error) {
            [sender endLoading];
            [self stop];
        }];
    }];

每当我尝试访问[self method]或在块外部定义的任何变量时,我总是得到BAD_ACCESS.有任何想法吗？谢谢!

Answer 1

你得到的原因EXC_BAD_ACCESS是因为默认情况下会在堆栈上创建块,所以如果你用assign属性引用它们,当堆栈被拆掉时它们就会停止存在.

为了解决这个问题,您应该将块复制到堆中.一种方法是使用copy而不是assign在定义属性时.

将您的声明更改为

@property(copy, nonatomic) ButtonClicked onButtonClicked;

并且在分配块时使用其setter/getter而不是直接访问ivar

- (void)setClickBlock:(ButtonClicked)buttonClicked {
    self.onButtonClicked = buttonClicked;
}
- (void)internalButtonClicked {
    DLog(@"internal clicked");
    if (self.onButtonClicked) {
        self.onButtonClicked(self, self.userInfo);
    }
}