定义、使用、循环引用

1:oc中blcok是一个匿名函数，常用于回调 2:oc中blcok的三种常见定义： #import "HttpTool.h" typedef void(^myBlock)(NSString *name); @interface HttpTool () //typedef定义法 - (void)httpToolBlock:(myBlock)callBlock; // void(^block名字)(参数列表) @property (nonatomic, copy)void(^callBlock)(NSString *name); // 方法的block定义 //(void(^)(NSString *str))callBlock - (void)blockFunc:(void(^)(NSString *name))callBlock; @end 3:对于block中经常会注意循环引用的问题：最好的办法是使用weckself，常见写法： #define WS(weakSelf) __weak __typeof(&*self)weakSelf = self; 1. __weak XJViewController *weakSelf = self; 2. __weak typeof(self) weakSelf = self; 3. __weak __typeof(self)weakSelf