将引用作为Objective-C中的实例变量阻止

Question

我想知道是否可以将对匿名函数(块)的引用存储为Objective-C中的实例变量.

我知道如何使用委托,目标行动等.我不是在谈论这个.

Answer 1

当然.

typedef void(^MyCustomBlockType)(void);

@interface MyCustomObject {
  MyCustomBlockType block;
}
@property (nonatomic, copy) MyCustomBlockType block; //note: this has to be copy, not retain
- (void) executeBlock;
@end

@implementation MyCustomObject
@synthesize block;

- (void) executeBlock {
  if (block != nil) {
    block();
  }
}

- (void) dealloc {
  [block release];
  [super dealloc];
}
@end

//elsewhere:

MyCustomObject * object = [[MyCustomObject alloc] init];
[object setBlock:^{
  NSLog(@"hello, world!");
}];

[object executeBlock];
[object release];

Answer 2

是的,您当然可以存储对Objective-C块的(副本)的引用.变量声明有点毛茸茸,就像C函数指针一样,但除此之外它没有问题.对于带有id和返回void 的块:

typedef void (^MyActionBlockType)(id);

@interface MyClass : NSObject 
{

}

@property (readwrite,nonatomic,copy) MyActionBlockType myActionBlock;
@end

会做的.