down static method
decrease system volume by step, step must be in range 0.0, 1.0.
return the system volume value after decrease.
the return volume value may be not equals to the current volume - step.
Implementation
static Future<double?> down({double step = _defaultStep}) {
if (step < 0.0 || step > 1.0) {
return Future.error(
ArgumentError.value(step, "step must in range [0.0, 1.0]"));
} else {
return FijkPlugin._channel
.invokeMethod("volumeDown", <String, dynamic>{'step': step});
}
}