定时器.周期性颤振，

Question

@override
void initState() {
 super.initState();

 bool isLastPage = (_currentPage.round() == sliderArrayList.length - 1 );

 //Trying to build automatic scrollable
 Timer.periodic(Duration(seconds: 5), (Timer timer) {
  if (_pageController.hasClients && !isLastPage) {
    _pageController.nextPage(
      duration: Duration(milliseconds: 200),
      curve: Curves.easeIn);}
  if(isLastPage){
    timer.cancel();
  }
 });
}

I am trying to build a periodic timer which scrolls pages in pageview, flutter after every 5 seconds, however it keeps on scrolling even after the last page. I have tried to implement the above method if(isLastPage){timer.cancel();} and it doesnt work.

Answer 1

You've to evaluate that expression everytime timer ticks. Also, Put the isLastPage check before the hasClients check.

Timer.periodic(Duration(seconds: 5), (Timer timer) {
  final isLastPage = _currentPage.round() == sliderArrayList.length - 1;
  if (isLastPage) {
    timer.cancel();
    return;
  }
  if (_pageController.hasClients) {
    _pageController.nextPage(
      duration: Duration(milliseconds: 200),
      curve: Curves.easeIn);
  }
});