Add custom icon to SymbolOptions

[miladsalimiiii]

For adding icon image to symbols we use this :

.withIconImage(MAKI_ICON_HARBOR)

in

            symbolLayerIconFeatureList.add(
                SymbolOptions()
                    .withLatLng(point.latitude?.let { point.longitude?.let { latitude ->
                        LatLng(it,
                            latitude
                        )
                    } })
                    .withIconImage(MAKI_ICON_HARBOR)
                    .withIconSize(2.0f)
            )

.withIconImage() argument is String like MAKI_ICON_HARBOR .

How can we see all icon options in string and how can we add our drawable as iconImage in .withIconImage() ?