New to android need to understand “?android:attr/actionBarSize”

Question

I was going through Lars Vogel\'s tutorial on using Fragments and I came across the following code:

android:layout_marginTop=\"?android:attr/actionBarSize\"
         


        

Answer 1

Instead of write Numerical number in value of android:layout_marginTop , you can use the height specified by actionBarSize like an Example in Android Training .

You can use ?android:attr or ?attr [ in case support library ] If you need to use any android attributes[ attr ] can be found in R.attr

For More Description about ?android:attr Quiz 1 ,Quiz 2