iphone - 创建 block 变量

Question

我有函数，在其中我将块变量 blockIfLoadingImageFromServer 添加到数组:

- (UIImage *)getImageWithblockIfLoadingImageFromServer:(void (^)(UIImage *imageCompleted))blockIfLoadingImageFromServer
{
      [array addObject:blockIfLoadingImageFromServer];
}

然后，我想获取此变量，但是我不知道如何。我试过了:

(void (^)(UIImage *imageCompleted))blockIfLoadingImageFromServer = [array objectAtIndex:0];
void (^)(UIImage *imageCompleted) *blockIfLoadingImageFromServer = [array objectAtIndex:0];

但这会产生错误(语法错误)。我怎样才能做到这一点？

Answer 1

我通常使用typedef来简化生活:

typedef void (^ImageBlock)(UIImage*);

接着:

- (void) doSomethingWithBlock: (ImageBlock) block
{
    [array addObject:[block copy]];
}

- (void) doSomethingElse
{
    ImageBlock block = [array lastObject];
    …
}