Android Volley Always Fails With Proguard

The goal is to deploy an application with obfuscation and minification applied. Usual builds without minification work fine. But when minifyEnabled is switched to true, everything

Solution 1:

Should admit, that even with all information provided, my question was very difficult to analyze, because of many possible sources of described errors.

I'll begin from the end of my question. Guava didn't work correctly, because ProGuard just excluded Guava's Subscribe-methods from my code to be packed. ProGuard removes unused code, and as far as Subscribe-methods are analyzed as unused (even IDE don't highlight them as used ones) ProGuard has decided to remove these methods. To solve this issue, we should keep Subscribe-methods from ProGuard's processing:

# Keep subscribe-methods from deletion
-keepclassmembers class ** {
  @com.google.common.eventbus.Subscribe <methods>;
}

And my first problem - when Volley always calls onErrorResponse callbacks in all requests being fired. I used a custom deserializer for Json-repsonses which also checks, if server has provided some required fields (marked with a corresponding annotation). And, of course, ProGuard by default could not work correctly with these annotations and deserializer - that's why I had to keep these entities too:

# To make right deserialization
-keepclassmembers class ** {
  @com.some.package.server.JsonDeserializerWithOptions$FieldRequired public *;
}
-keep @interface com.some.package.server.JsonDeserializerWithOptions$FieldRequired
-keep classcom.some.package.server.JsonDeserializerWithOptions

Solution 2:

Its difficult the pinpoint any error with the logs, however you should try it without using proguard. skip the proguard file syntax and see if it works fine. Make sure you have multidex enabled, else your project will fail to execute.

android {

compileSdkVersion 21
buildToolsVersion "21.1.0"

defaultConfig {
    ...
    minSdkVersion 14
    targetSdkVersion 21
    ...

    // Enabling multidex support.
    multiDexEnabled true
}
...
}

dependencies {
    compile 'com.android.support:multidex:1.0.0'
}

More details : https://developer.android.com/studio/build/multidex.html