unable to compute hash of

The problem with API 23 and Google Play Services is still not resolved.

Just in case you get something like “unable to compute hash of /intermediates/classes-proguard/release/classes.jar” – just add a few lines to the

-dontwarn org.apache.http.**

Stack overflow thread:
Star google bug:


Obfuscate your Android application

Proguard is the nice way to obfuscate your Android application to prevent reverse engineering. Here is Google tutorial for this

But you can face some difficulties with it:

  1. To minimize risk of “class not found” exceptions – don’t obfuscate external libraries that you have in your project. Add -keep option to proguard.cfg
    -keep public class** {
        public protected *;
  2. If you are using reflection in your code – add these classes to the exclude list:
    -keepclassmembers class * {
        public static void buildUriMatcher(android.content.UriMatcher, java.lang.String);
  3. Stop using onClick listeners in xml resources!:) Or also add an exception:
    public void on*(android.view.View);
  4. In Eclipse you can easily get “conversion to dalvik format failed with error 1”:

    Don’t worry – don’t obfuscate external libraries + don’t use Eclipse for export signed application. Just create build.xml for Ant and all will be just perfect!

    Read more about this problem here:

  5. Try to reverse engineering your code with JD (as described here). You may need to remove some debug log String constants to make your code completely unreadable:)



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