I have an interesting observation and question, but first a comment. I have been using Delphi for 14 years and have taken a job developing an iOS mobile application using XE5. This is my first time using FMX and frankly I feel like I am stepping back in time many moons ago. In other words, if this is the future, then it feels like I have crippled. No problem though. Roll with the punches. Developing in this brave new world is not just a job. It is an adventure.
Now my question. Start a FMX mobile project using the "Header/Footer with Navigation" as your base. Then add an edit control (Edit1) to the first tab item. Then set the tab control align to none and move it to the right until you can clearly see the form itself. Then add an edit control (Edit2) to the form.
Now set the form's active control to Edit1 and run the app - no focus on Edit1. Now set the form's active control to Edit2 and run the app - focus is placed on Edit2. Interesting. Tab is a foreign word to tablets, right? Why have active control or even setfocus available? Is this an oversight by Embarcadero? Any thoughts?
Long story short I think they both have potential uses.
I use the SetFocus call to manually show the keyboard. Lets say the user navigates to a page where they're 100% sure to be putting in their username (or any text), I'll use ctrl.SetFocus to show the keyboard just to save them having to click (or is it press now?) on the edit.
I don't see ActiveControl being as useful, but it could definitely still be used. You could possibly use it to set up some sort of tabbing like structure for when the user presses Next on the keyboard (when the edit's ReturnKeyType is rkNext).