ios - dispatch_after 递归 vs NSTimer scheduledtimerwithtimeinterval

Question

我读了一段代码，它每秒检查数据并更新 UI。这听起来像我们通常使用 NSTimer scheduledtimerwithtimeinterval 所做的事情。但是这段代码是通过递归调用 dispatch_after 实现的，如下所示:

- (void) retriggerMethod {
    ... do stuff here, assuming you want to do it on first invocation ...
    dispatch_after( ..., ^{
        [self retriggerMethod];
    });
}

dispatch_after recursion 和 NSTimer scheduledtimerwithtimeinterval 有什么区别？使用前者是否存在潜在风险？因为我认为当您使用它时，只要不结束此递归，调用堆栈就会增长。

Answer 1

NSTimer:

1. Need a NSRunloop.
2. Can repeat.
3. Can be invalid anytime if u want to cancel.
4. Can only run with delegate.
5. High level API.

调度后:

1. Can be run everywhere that u want with dispatch_queue.
2. Can't repeat by itself.
3. Can't be cancel.
4. It run as block.
5. GCD.