dart - dart计时器定期文档令人困惑

Question

我的任务很长，我想在运行结束后的固定间隔内安排新的运行，我发现了这一点。以下是什么意思？特别是最后一段。

Timer.periodic(Duration duration, Function void callback(Timer timer))

Creates a new repeating timer.

The callback is invoked repeatedly with duration intervals until canceled with the cancel function.

The exact timing depends on the underlying timer implementation. No more than n callbacks will be made in duration * n time, but the time between two consecutive callbacks can be shorter and longer than duration.

In particular, an implementation may schedule the next callback, e.g., a duration after either when the previous callback ended, when the previous callback started, or when the previous callback was scheduled for - even if the actual callback was delayed.

Answer 1

假设您将计时器设置为每30秒运行一次。如果第二次调用该回调需要10秒才能完成，则对该回调的第三次调用可能是:

在第二个 call 开始后30秒

第二个通话结束后30秒(第二个通话开始后40秒，因为花费了10秒)，所以

计划第二个 call 运行30秒后(基于上述情况，可能已被延迟，例如，由于第一个 call 的持续时间)