getSnapToEdgeSpace method
获取吸附后回弹至与边缘的距离
Implementation
Future<double> getSnapToEdgeSpace() async {
var c = Completer<dynamic>();
var cmd = _ControllerCommand(ControllerEnumType.getSnapToEdgeSpace, completer: c);
try {
_commandController.add(cmd);
} catch (_) {
c.complete(0.0);
}
if (!_hasListeners) c.complete(0.0);
return c.future.then((value) => value is double ? value : 0.0);
}