This sample demonstrates how you can hide or show sublayers of a map image layer. Tap on the Sublayers button in the bottom toolbar to displays the list of sublayers. Each sublayer in the list has a switch, which can be used to toggle it's visibility.
How it works
The mapImageSublayers property on AGSArcGISMapImageLayer is used to get the list of AGSArcGISMapImageSublayer. Each of these sublayers has a property called isVisible, which is used to toggle visibility.