如何在Objective-C中声明Block?？
局部变量:
returnType (^blockName)(parameterTypes) = ^returnType(parameters) {...};类属性(property):
@property (nonatomic, copy) returnType (^blockName)(parameterTypes);方法声明中的参数:
- (void)someMethodThatTakesABlock:(returnType (^)(parameterTypes))blockName;方法调用中的参数:
[someObject someMethodThatTakesABlock:^returnType (parameters) {...}];typedef的方式:
typedef returnType (^TypeName)(parameterTypes);
TypeName blockName = ^returnType(parameters) {...};