How to center the content inside a linear layout?

Question

I\'m trying to center an ImageView inside a LinearLayout horizontally and vertically, but I just can\'t do it. The main reason why I\'m not using a

Answer 1

android:gravity can be used on a Layout to align its children.

android:layout_gravity can be used on any view to align itself in its parent.

NOTE: If self or children is not centering as expected, check if width/height is match_parent and change to something else