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.

Answer 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

Answer 2

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

Answer 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.

Answer 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

Answer 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.

Answer 6

Try to look up in the whole error message. It may contain info that you include a library twice. This was the problem in my case and it was fixed after removing duplicated includes.

Answer 7

Try add this code in your proguard-rules.pro:

-ignorewarnings 

It solved my problem.

Answer 8

I think your app build.gradle buildTypes > release > minifyEnabled is true

That cause you get this error message.

Avoid this error message, set buildTypes > release > minifyEnabled is false

---

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