Flutter/Dart - 在延迟或中断之前打开视图

Question

在问题"Open a view after a delay"，copsOnRoad 给出 结果如下：

import 'dart:async';

// 1. Option with Timer
Timer(Duration(seconds: 5), () {
  // 5s over, navigate to a new page
  Navigator.pushNamed(context, MaterialPageRoute(builder: (_) => Screen2()));
});


// 2. Option -- Using Future.delayed class
Future.delayed(Duration(seconds: 5), () {
  // 5s over, navigate to a new page
  Navigator.pushNamed(context, MaterialPageRoute(builder: (_) => Screen2()));
});

我想给用户一个选项来停止 Navigator.pushNamed 的执行 在等待的 5 秒内。这怎么可能？

Answer 1

您可以定义一个布尔值，如果它被取消，则推送或不喜欢：

import 'dart:async';

bool isCancelled = false;

// 1. Option with Timer
Timer(Duration(seconds: 5), () {
  // 5s over, navigate to a new page
  Navigator.pushNamed(context, MaterialPageRoute(builder: (_) => Screen2()));
});


// 2. Option -- Using Future.delayed class
Future.delayed(Duration(seconds: 5), () {
  if(!isCancelled )
  Navigator.pushNamed(context, MaterialPageRoute(builder: (_) => Screen2()));
});

and a button to change state of isCancelled