I recently ran into the problem that the Citrix MDX Toolkit could not find the Android SDK. Normally you have the option to select the main folder of the Android SDK, but this option was not available for me. Fortunately there is a good workaround for this problem.
To solve this problem, open Finder and browse to the Android SDK folder. Open the build-tools folder and start searching for the zipalign program which is located somewhere in a subfolder (depending on the Android SDK version you are using).
Right click the zipalign file and open the file Info. Highlight the file location path (after Where) and copy it.
In Finder browse to Programs > Citrix > MDXToolkit and open the android_settings.txt
Remove the // in front of the PATH statement and past the file location path of the zipalign after the = sign (see screenshot above) and save the file.
This solved my problem and I was able to wrap Android applications again.