How to concatenate multiple strings in android XML? [duplicate]

Problem
I would like to be able to do something like that in Android XML code:

<string name="title">@string/app_name test</string>
<string name="title2">@string/app_name @string/version_name</string>

Regarding first line of code compiler shows this error

No resource found that matches the given name (at 'title' with value '@string/app_name test')

and regarding second line of code compiler shows this error

No resource found that matches the given name (at 'title2' with value '@string/app_name @string/version_name')

Question
Does anybody know how to concatenate multiple strings in Android XML?

Rationale
It is bad practice to duplicate variable values in many places of code (in this case XML).

I've tried to do a similar maneuver myself but I was told this is not doable in Android.

The interesting thing is that you get an error message that indicates that it indeed is possible but due to errors in resource matching it's not possible right now. (Are you sure you have defined the "app_name" and "version_name" strings before the "title" and "title2" strings?)

You can however do something like:

<string name="title">%1$s test</string>
<string name="title2">%1$s %2$s</string>

<string name="app_name">AppName</string>
<string name="version_name">1.2</string>

And then from Java code do something like:

Resources res = getResources();
String appName = res.getString(R.string.app_name);
String versionName = res.getString(R.string.version_name);

String title = res.getString(R.string.title, appName);
String title2 = res.getString(R.string.title2, appName, versionName);

More about formatting strings in Android.

Hope this helps.