objective-c - block 引用作为Objective-C中的实例变量

Question

我想知道是否可以将匿名函数( block )的引用存储为 Objective-C 中的实例变量。

我知道如何使用委托(delegate)、目标 Action 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];