run method

void run()

启动倒计时

Implementation

void run() {
  if (isActive || periodic <= 0 || totalTime <= 0) return;
  Duration duration = Duration(milliseconds: periodic);
  _runCallback(totalTime);
  timer = Timer.periodic(duration, (Timer timer) {
    totalTime -= periodic;
    if (totalTime >= periodic) {
      _runCallback(totalTime);
    } else if (totalTime == 0) {
      _runCallback(totalTime);
    } else {
      cancel();
    }
  });
}