handleBack method
Handle a back gesture. Returns true when the flow consumed it by stepping backwards; false means the host should close the flow.
Implementation
bool handleBack() {
// Mid-submit, back does nothing rather than tearing down a request in flight.
if (_step == _Step.submitting) return true;
// From the form, back returns to the annotations it came from.
if (_step == _Step.form && widget.screenshot != null) {
setState(() => _step = _Step.annotate);
return true;
}
return false;
}