previousStep method
void
previousStep()
Returns to the previous step.
Decrements the current step index by 1. Does not validate if the previous step exists - callers should check bounds.
Example:
if (controller.value.currentStep > 0) {
controller.previousStep();
}
Implementation
void previousStep() {
value = StepperValue(
stepStates: value.stepStates,
currentStep: value.currentStep - 1,
);
}