[[self class] cancelPreviousPerformRequestsWithTarget:self selector:@selector(todoSomething:) object:btn]; [self performSelector:@selector(todoSomething:) withObject:btn afterDelay:0.2f];
在0.2秒时间间隔内多次点击只响应一次点击事件

[[self class] cancelPreviousPerformRequestsWithTarget:self selector:@selector(todoSomething:) object:btn]; [self performSelector:@selector(todoSomething:) withObject:btn afterDelay:0.2f];