Thanks for the reply. May I inquire to confirm the following info: Are you using Zoom default UI or Custom UI on iOS SDK?
If you are using the Zoom default UI, switching between views can be simply done by swiping the screen to the left or to the right(If you have not disabled the gallery view). So switching is available in default UI, we just do not have an interface to do this programmatically.
If you are using Custom UI, since the main concept of Custom UI is you have all the control of your meeting UI, so you will implement your active speaker view and gallery view; Switching between views usually done by the developer since we do not know which view is the active view and which view is the gallery view.
Hope this helps. Thanks!