Flutter - How to delay a function for some seconds-CodePudding

I have a function which returns false when the user select incorrect answer.

tappedbutton(int index) async {
 final userAnswer = await userAnswer();
   if (userAnswer) {
// Executing some code
}else{
ErrorSnackbar(); // This snackbar takes 2 second to close.
}

My objective is to delay calling the function for two seconds(user can click the button again , with no action triggering) after the user selects the wrong answer and to prevent the click immediatly. How can i achieve it?

CodePudding user response：

You'll have to add an helper variable in the outer scope, that will indicate whether the user is on an answer cooldown or not.

The shortest solution will be:

var answerCooldownInProgress = false;
tappedbutton(int index) async {
  // Ignore user taps when cooldown is ongoing
  if (answerCooldownInProgress) {
    return;
  }
  final userAnswer = await userAnswer();
  if (userAnswer) {
    // ...
  } else {
    ErrorSnackbar();

    answerCooldownInProgress = true;
    await Future.delayed(const Duration(seconds: 2));
    answerCooldownInProgress = false;
  }
}

CodePudding user response：

You can use Future.delay or Timer() class to achieve that.

CodePudding user response：

In order to delay a function you can do below code or use Timer() class

tappedbutton(int index) async {
               await Future.delayed(Duration(seconds: 2));
}

CodePudding user response：

I don't think that your goal is to delay the function. You're trying to find a way to let the user wait until the ErrorSnackbar is gone, right?

Try this approach. It saves the time when a button was clicked the last time and cancels every button press until 2 seconds have passed.

DateTime lastPressed = DateTime(0);

  tappedButton(int index) async {
    DateTime now = DateTime.now();
    if (lastPressed.difference(now).inSeconds < 2) {
      // button pressed again in under 2 seconds, cancel action
      return;
    }
    lastPressed = now;
    final userAnswer = await userAnswer();
    if (userAnswer) {
      // answer correct
    } else{
      // answer incorrect
      ErrorSnackbar();
    }
  }