Block相关备忘

block定义

int (^addBlock)(int a,int b) = ^(int a,int b){
    return a+b;
};

typedef常用block

typedef int (^SomeBlock)(BOOL flag,int value);
SomeBlock block = ^(BOOL flag,int value){
};

常用

//用来在块内修改变量
__block NSInteger count = 0;

//用来避免出现循环引用
__weak typeof (self) weakSelf = self;

//用来加强一下引用，避免weakSelf被释放掉
__strong typeof (self) strongSelf = weakSelf;