Use an ImageView, there are official icon packs where you can find an ic_action_collapse.png
and ic_action_expand
.
(You can find in them in the folders 02_navigation_expand
and 02_navigation_collapse
) in dark and light and the 4 resolution variants (mdpi
, hdpi
, xhdpi
and xxhdpi
).
Just copy the directories into your res
folder and the correct resolution will be picked by android automaticall.