Let’s say I just added two standard widgets — CheckBox and CheckedTextView. The first one has nice, clear padding despite that fact I didn’t set any, and there is no padding set in .xml file. The other one comes without any padding.
Now, I could get the value (fixed) of the padding from CheckBox by trial&error. But my question is how to set it in kind of dynamic fashion — i.e. if in Android 7.0 padding for CheckBox will be “20sp” and I set “10sp” (because it is now 10sp — I am making this up) then my two widgets would be with different paddings.
And I would like to have a consistent padding. So how to set something like "?android/default_padding" for padding?
Clarification: I am interested in using the system default padding, not hardcoding the same value made up by me over all widgets.
I looked it up for you, in API Level 10 (and also on every other Android platform) Android uses 9-Patch images with prefdefined paddings (there is no padding declared in the Selector), e.g. I mesured the checkbox and it as this pasddings: left, right: 6dp; top, bottom: 12dp. And the default button has a padding of 10dp; so there is no default padding as far as I can tell. But 10dp is good in most cases. Also, it just really depends on the screensize of your device. You will have to declare your own prefered padding like Daniel suggested. E.g: In your Values file 10dp and in values-large maybe 15.
Edit:
Here is the default checkbox for mdpi on Android 2.3.3: