Missing styles, Using CardView in android studio

Question

With CardView as root layout in xml file(for a custom view), i get an error from android studio-

Missing styles. Is the correct theme chosen for this layout? Use the Theme combo box above the layout to choose a different layout, or fix the theme style references. Failed to find style with id 0x7fff000e in current theme .

I tried choosing different themes for the layout, none worked it seems.
I am using the new appCompatActivity in my app.
any theme works fine with the old ActionBarActivity.

Answer 1

Adding the elements below to the AppTheme helped me to solve a similar problem

    <item name="colorPrimary">@color/primary</item>
    <item name="colorPrimaryDark">@color/primary_dark</item>
    <item name="colorAccent">@color/accent</item>

Answer 2

I guess this is a bit ate for your question but just in case someone needs it:

Mine was solved after restarting android studio using the below option:

File -> Invalidate Caches/Restart...