How do I apply mathematical operations to Android dimensions?

Question

How do I avoid this hardcoded math...

<resources>  <dimen name="uno">10dip</dimen>  <dimen name="dos">6dip</dimen>  <dimen name="uno_plus_dos">16dip</dimen> </resources>  <Button   android:layout_marginTop="@dimen/uno_plus_dos" /> 

...and covert it to something like this?

<Button  android:layout_marginTop="@dimin/uno + @dimen/dos" /> 

Answer 1

You don't, sorry. Layout XML files do not support expressions. You either:

• Leave it as @dimen/uno_plus_dos, or
• Set your margins in Java code, where you can replace a single resource with a bunch of extra lines of code, or
• Write your own layout preprocessor that handles expressions like this

UPDATE The data binding library supports some operations in its expressions. I am uncertain if it can handle this specific scenario.

Answer 2

One trick for simple addition is to use margin + padding.