Gradle Build Failure

Question

My project compiles and executes well on debug mode but when i try to generate a signed apk, errors arise. This appears on the message log:

:app:proguardRelease
Warning:android.support.v4.app.DialogFragment: can't find referenced class android.support.v4.app.DialogFragment$DialogStyle
Warning:android.support.v4.app.FragmentTransaction: can't find referenced class android.support.v4.app.FragmentTransaction$Transit
Warning:android.support.v4.view.ViewCompat: can't find referenced class android.support.v4.view.ViewCompat$ResolvedLayoutDirectionMode
Warning:android.support.v4.view.ViewCompat: can't find referenced class android.support.v4.view.ViewCompat$LayoutDirectionMode
Warning:android.support.v4.view.ViewCompat: can't find referenced class android.support.v4.view.ViewCompat$LayerType
Warning:android.support.v4.view.ViewCompat: can't find referenced class android.support.v4.view.ViewCompat$AccessibilityLiveRegion
Warning:android.support.v4.view.ViewCompat: can't find referenced class android.support.v4.view.ViewCompat$ImportantForAccessibility
Warning:android.support.v4.view.ViewCompat: can't find referenced class android.support.v4.view.ViewCompat$OverScroll
Warning:android.support.v4.widget.DrawerLayout: can't find referenced class android.support.v4.widget.DrawerLayout$EdgeGravity
Warning:android.support.v4.widget.DrawerLayout: can't find referenced class android.support.v4.widget.DrawerLayout$LockMode
Warning:android.support.v4.widget.DrawerLayout: can't find referenced class android.support.v4.widget.DrawerLayout$State
Warning:there were 11 unresolved references to classes or interfaces.
         You may need to add missing library jars or update their versions.
         If your code works fine without the missing classes, you can suppress
         the warnings with '-dontwarn' options.
         (http://proguard.sourceforge.net/manual/troubleshooting.html#unresolvedclass)
Exception while processing task 
java.io.IOException: Please correct the above warnings first.
    at proguard.Initializer.execute(Initializer.java:473)
    at proguard.ProGuard.initialize(ProGuard.java:233)
    at proguard.ProGuard.execute(ProGuard.java:98)
    at proguard.gradle.ProGuardTask.proguard(ProGuardTask.java:1074)
    at com.android.build.gradle.tasks.AndroidProGuardTask.doMinification(AndroidProGuardTask.java:139)
    at com.android.build.gradle.tasks.AndroidProGuardTask$1.run(AndroidProGuardTask.java:115)
    at com.android.builder.tasks.Job.runTask(Job.java:48)
    at com.android.build.gradle.tasks.SimpleWorkQueue$EmptyThreadContext.runTask(SimpleWorkQueue.java:41)
    at com.android.builder.tasks.WorkQueue.run(WorkQueue.java:227)
    at java.lang.Thread.run(Thread.java:745)
:app:dexRelease UP-TO-DATE
:app:crashlyticsStoreDeobsRelease
:app:crashlyticsUploadDeobsRelease
:app:validateExternalOverrideSigning
:app:packageRelease FAILED
Error:Execution failed for task ':app:packageRelease'.
> Unable to compute hash of /home/kombo/RAL/Mpasho/app/build/intermediates/classes-proguard/release/classes.jar

I have tried every possible way of remedying this by updating my build tools, using the latest gradle version, checking all the dependencies and the error still shows up.

I am pretty sure the v4 support library is present in the project since no errors arise in debug mode.

Solution 1

I also had this issue when upgrading everything that is built related to 23 (Android Libraries, SDK etc).

This proguard configuration fixed it for me:

-dontwarn org.apache.http.**
-dontwarn android.net.http.AndroidHttpClient
-dontwarn com.google.android.gms.**
-dontwarn com.android.volley.toolbox.**

Source

Solution 2

Turns out I had omitted the getDefaultProguardFile('proguard-android.txt') line on the proguard files and was just using proguard-rules.pro

Solution 3

added these two line in progaurd

-dontwarn android.net.http.AndroidHttpClient
-dontwarn com.google.android.gms.**

and it works..

It is related to library used in project.

Solution 4

The default ProGuard file already has a rule to ignore support library warnings. If you don't have it you can add to your file

-dontwarn android.support.**

but would be better to add the default one. See Proguard configuration@Android Developers

Solution 5

This also could happen due to errors/warnings related to included .jar files Check in build output for proguard warnings/errors.

I had issue related to opencsv jar file. Hint by Lakedaemon in above comment helped me and its solved.

View more solutions

Comments

[Alex Kombo]

That only gets me as far as removing the warnings. But this error still persists, Error:Execution failed for task ':app:packageRelease'. > Unable to compute hash of /home/kombo/RAL/Mpasho/app/build/intermediates/classes-progu‌​ard/release/classes.‌​jar

[Lakedaemon]

I had the same problem. Cleaning, clearing caches didn't resolve it. When I looked higher in the build log, I noticed that proguard was spouting some warnings. I probably had 2 libraries that were sharing some code (duplicate classes..) I removed one of the offending library and it fixed my proguard issue --> look at your build output for proguard warnings/errors

[Brill Pappin]

Same problem... no solution.

[Niklas]

@dangalg checkout my answer

[Diego Palomar]

This is very frustrating, I have tried almost everything and I can not fix it :$

[justadev]

Good find. This was it.

[Roon13]

Worked for me too!! after 3 hrs of searching!! Thanks a lot sir!!

[Ahmed]

Same problem, no solution yet

[Niklas]

@Ahmed in your proguard configuration file

[GuilhE]

Not working for me: stackoverflow.com/questions/35804397/proguard-and-apache-leg‌​acy

[IgorGanapolsky]

This is assuming people are using volley.

[Nativ]

so you are not using proguard at all mate. try to decompile you apk and see that you get the exact project files

[Bolein95]

Thanks! You saved my day

[Ivan Leong]

This is not a solution is you need pro-guard enabled