块而不是performSelector：withObject：afterDelay： [英] Blocks instead of performSelector:withObject:afterDelay:

问题描述

我经常想在未来几秒钟内执行一些代码。现在，我这样解决：

I often want to execute some code a few microseconds in the future. Right now, I solve it like this:

- (void)someMethod
{
    // some code
}

并且：

[self performSelector:@selector(someMethod) withObject:nil afterDelay:0.1];

它工作，但我必须每次创建一个新的方法。是否可以使用块而不是这个？基本上我正在寻找一种方法如：

It works, but I have to create a new method every time. Is it possible to use blocks instead of this? Basically I'm looking for a method like:

[self performBlock:^{
    // some code
} afterDelay:0.1];

这对我来说非常有用。

推荐答案

没有内置的方法可以做到这一点，但通过类别添加并不难：

There's no built-in way to do that, but it's not too bad to add via a category:

@implementation NSObject (PerformBlockAfterDelay)

- (void)performBlock:(void (^)(void))block 
          afterDelay:(NSTimeInterval)delay 
{
    block = [[block copy] autorelease];
    [self performSelector:@selector(fireBlockAfterDelay:) 
               withObject:block 
               afterDelay:delay];
}

- (void)fireBlockAfterDelay:(void (^)(void))block {
    block();
}

@end

http://www.mikeash.com/pyblog/friday-qa-2009-08-14-practical-blocks.html\"> Miley Ash 的基本实施。

Credit to Mike Ash for the basic implementation.

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