How to enable ProGuard obfuscation in Android Studio?

I have to protect my app by enabling Proguard obfuscation in Android Studio. I have searched for the process of how to apply it but i did not get any clear solution. When i try it, i always get an error. So can anyone tell me the clear steps to apply it in my app?

I am doing this by the following steps:

1. In Android Studio, open up an Android project.

2. Change to Project View.

3. Change the following line:

   minifyEnable false to minifyEnable true

4. Set ProGuard Rules(optional)

   4.1 In Project View, select the proguard-rules.pro file.

   4.2 Add in the following lines to tell ProGuard not to obfuscate certain classes.

   -keepclassmembers class com.dom925.xxxx 
   {
     public *
   }
   

Error that I am getting by following the steps are

Error:Execution failed for task ':app:packageRelease'. Unable to compute hash of D:\Android\Pojectname\app\build\intermediates\classes-proguard\release\classes.jar

To enable ProGuard in Android Studio.

Below is the sample how to enable default ProGuard in Android Studio.

1. Go to the build.gradle file of app
2. enable the minifyEnabled true
3. enable shrinkResources true to reduce the APK size

4. proguardFiles getDefaultProguardFile('proguard-android.txt') to enable the default one. If you want to use your own proguard file then use the below rules.

   buildTypes {
       release {
           debuggable false
           minifyEnabled true
           shrinkResources true
           proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
       }
   
       debug {
           debuggable true
           minifyEnabled true
           shrinkResources true
           proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
       }
   }
   

The link with ProGuard settings for Android and other settings are available in these links:

• Default ProGuard file
• Gist with example

For more detail go through this link

I figured out the problem:

Open up the proguard-rules.pro for your project and add this to the bottom:

-dontwarn java.nio.file.Files
-dontwarn java.nio.file.Path
-dontwarn java.nio.file.OpenOption
-dontwarn org.codehaus.mojo.animal_sniffer.IgnoreJRERequirement

Basically how I solved it was this I tried to run my app in 'release' mode and got a bunch of errors similar to this guy here: https://github.com/square/okio/issues/144

I pretty much followed what he said and fixed it.

Hope this can help others with generating their APK's!

visit more detail here :

Error:Execution failed for task ':app:packageRelease'. > Unable to compute hash of /../AndroidStudioProjects/../classes.jar

if you are building the android project with jack, then it will automatically do the shrinking, obfuscation, repackaging and multidex. Just add below in :

defaultConfig {
       jackOptions {
            enabled true
        }        
    }

and in build types, mention the project proguard file :

buildTypes {
        release {
            // Jack build environment does not require minifyEnabled or shrinkResources.
            // Conceptually, the jack compiler consolidates the functionality of javac, ProGuard, and dex in a single conversion step
            //minifyEnabled = true      
            //shrinkResources true

            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-project.txt'
       }

       debug {
...................
        }
    } 

To disable the ProGuard obfuscation, it is required to add below line in your proguard-project.txt file

####No obfuscation
-dontobfuscate