IOS 代码块block :capturing self strongly in this block is 告警

我们在代码块中使用对象的成员时(成员变量是属性strong，MRC估计是retain时效果一样，使用方法时也一样):

警告：

capturing self strongly in this block is likely to lead to a retain cycle

意思应该是block会retain一次，所以使用前最好 __block MyClass* bObject = self;

简单代码如下：

    __block LoginViewController *  blockSelf = self;        if (name ==nil || name.length<=3) {          [self.alert addButton:@"OK" actionBlock:^(void) {         [blockSelf.userNameField  becomeFirstResponder];        }];        [self.alert showInfo:self title:@"信息不完整" subTitle:@"用户名长度必须大于3." closeButtonTitle:nil duration:0.0f ];                self.checkFormStatus = FALSE;        self.alert = nil;                return FALSE;    }

代码里添加了

__block LoginViewController *  blockSelf = self;

同事替换了之前的写法 self.userNameField  改成 blockSelf.userNameField 

告警就木有了！