Welcome to the Treehouse Community

Want to collaborate on code errors? Have bugs you need feedback on? Looking for an extra set of eyes on your latest project? Get support with fellow developers, designers, and programmers of all backgrounds and skill levels here with the Treehouse Community!

Looking to learn something new?

Treehouse offers a seven day free trial for new students. Get access to thousands of hours of content and join thousands of Treehouse students and alumni in the community today.

Start your free trial

Android Styles and Themes in Android Themes and Compatibility AppCompat and Themes

1 Answer

it's used to refer to the values of an attribute which are already built-in on Android and available to use such as text appearance, font size, themes, and so on, on the other hand ?attr is used to refer the value of an attribute which you have defined on your own in your application.

you can check it out the link below for further reading: https://developer.android.com/guide/topics/resources/accessing-resources.html#ReferencesToThemeAttributes