Question: Let's say we have strings\_test.xml, which stores string values for testing and should be shown in a debug-release. When the apk gets build as a release version all values should be change to an empty string e.g. `<string name="test_some_card_text">@string/empty</string>`.

Is there a possibility to achieve this?

As always, thanks in advance.

Answer: 
As @Aditya Naik said it is possible using Flavors. 
Official doc says

> 
> BuildType -> Flavor -> main -> Dependencies.
> 
> 
> This means that if a resource is declared in both the Build Type and in main, the one from Build Type will be selected.
> 
> 
> Note that for the scope of the merging, resources of the same (type, name) but different qualifiers are handled separately.
> 
> 
> This means that if src/main/res has 
> 
> 
> * res/layout/foo.xml
> * res/layout-land/foo.xml 
> 
> 
> and src/debug/res has
> * res/layout/foo.xml   
>   
> 
>  Then the merged resource folder will contain the default foo.xml from src/debug/res but the landscape version from src/main/res
> 
> 
> 

**for more info visit [Official doc - Resource Merging](http://tools.android.com/tech-docs/new-build-system/resource-merging)**
It is not possible to change the string value after creation of the apk.
But you can assing the value to text or edittext ... etx dynamically after creation of the apk.