In AOSP Code ,there are many TextView Resource use "textSize" in style.xml to limit the text size, by in a normal alllication ,they use "android:textSize" to limit text size.
So what's the different between those two things?
In style.xml file the textSize is used for mentioning default text size value of that style.
so whenever you call that style in your view you will get that size of text.
Other hand in android:textSize we hard code the text size of that view.
Hope that make sense.