To be clear, Tano’s solution is sufficient to answer this question. But, in case others run into the same use case I did, here’s some more background that may potentially help you…
I had been running into this issue specifically while trying to make a non-editable Material Exposed Dropdown Menu and set it’s initial value programmatically. The documentation to create this type of “dropdown” can be found in the Exposed Dropdown Menus section here, which suggests a mechanism using TextInputLayout and AutocompleteTextView (even if you don’t want autocomplete functionality).
Failed Solution 1:
At first glance setListSelection() and getListSelection() seemed like they might do the trick. But after many trials, I learned that they may not be sufficient because they only work when the list popup isShowing(). So for example, if you simply want to set the initial selection without having to show the list popup first, this will not work.
Failed Solution 2:
Then I tried setText() which showed the proper text in my textbox. Yay! But wait! When I clicked on the text view, only a subset of options in the list popup were shown for some reason. Why was that? The key thing to keep in mind here is that since this is an autocomplete textview, it by default filters out options based off of the text in the textview. This might not be apparent, especially if you’re solely using this control for the sake of making a simple non-editable dropdown selector.
Solution:
This brings us to our actual solution (suggested by Tano)… setText() with filter as false will turn off the filtering capabilities AND it will not change the contents of your list popup.
autoCompleteTextView.setText(myText, false);