Unable to sign release APK - :app:shrinkReleaseMul

Question

I'm trying to generate a signed apk and the log keeps showing me the following error:

:app:compileReleaseJavaWithJavac
Note: Some input files use or override a deprecated API.
Note: Recompile with -Xlint:deprecation for details.
:app:compileReleaseNdk UP-TO-DATE
:app:compileReleaseSources
:app:collectReleaseMultiDexComponents
:app:proguardRelease
Warning:com.google.android.gms.internal.zzac: can't find referenced class android.net.http.AndroidHttpClient
Warning:com.google.android.gms.internal.zzw: can't find referenced method 'void addHeader(java.lang.String,java.lang.String)' in program class com.google.android.gms.internal.zzw$zza
Warning:com.google.android.gms.internal.zzw$zza: can't find referenced method 'void setURI(java.net.URI)' in program class com.google.android.gms.internal.zzw$zza
Warning:com.ironsource.mobilcore.j: can't find referenced method 'void setLatestEventInfo(android.content.Context,java.lang.CharSequence,java.lang.CharSequence,android.app.PendingIntent)' in library class android.app.Notification
Warning:com.mopub.volley.toolbox.HttpClientStack: can't find referenced method 'void addHeader(java.lang.String,java.lang.String)' in program class com.mopub.volley.toolbox.HttpClientStack$HttpPatch
Warning:com.mopub.volley.toolbox.HttpClientStack$HttpPatch: can't find referenced method 'void setURI(java.net.URI)' in program class com.mopub.volley.toolbox.HttpClientStack$HttpPatch
Warning:com.mopub.volley.toolbox.Volley: can't find referenced class android.net.http.AndroidHttpClient
Warning:there were 4 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)
Warning:there were 4 unresolved references to program class members.
         Your input classes appear to be inconsistent.
         You may need to recompile the code.
         (http://proguard.sourceforge.net/manual/troubleshooting.html#unresolvedprogramclassmember)
Warning:there were 1 unresolved references to library class members.
         You probably need to update the library versions.
         (http://proguard.sourceforge.net/manual/troubleshooting.html#unresolvedlibraryclassmember)
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:shrinkReleaseMultiDexComponents FAILED
Error:Execution failed for task ':app:shrinkReleaseMultiDexComponents'.
> java.io.IOException: The output jar [<project_path>\app\build\intermediates\multi-dex\release\componentClasses.jar] must be specified after an input jar, or it will be empty.

Below is my app-level build.gradle:

apply plugin: 'com.android.application'

android {
    compileSdkVersion 23
    buildToolsVersion "23.0.1"

    defaultConfig {
        applicationId "com.my.app"
        minSdkVersion 14
        targetSdkVersion 23
        versionCode 25
        versionName "2.5"

        // Enabling multidex support.
        multiDexEnabled true
    }
    buildTypes {
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
        }
    }

    dexOptions {
        incremental true
        javaMaxHeapSize "2048M"
    }
}

repositories {
    mavenCentral()
    maven { url "https://jitpack.io" }
}

dependencies {
    compile 'com.android.support:multidex:1.0.1'
    compile 'com.android.support:appcompat-v7:23.0.1'
    compile 'com.android.support:design:23.0.1'
    compile 'com.android.support:recyclerview-v7:23.0.1'
    compile 'com.google.android.gms:play-services:8.1.0'
    compile 'com.google.code.gson:gson:2.3.1'
    compile 'com.squareup.okhttp:okhttp:2.4.0'
    compile 'com.facebook.android:facebook-android-sdk:4.2.0'
    compile 'me.dm7.barcodescanner:zxing:1.7.2'
    compile 'de.hdodenhof:circleimageview:1.3.0'
    compile 'com.scottyab:secure-preferences-lib:0.1.3'
    compile 'com.soundcloud.android:android-crop:1.0.0@aar'
    compile('com.afollestad.material-dialogs:core:0.8.1.0@aar') {
        transitive = true
    }
    compile('com.mopub:mopub-sdk:3.13.0@aar') {
        transitive = true
    }
    compile project(':android-support-v4-preferencefragment')
    compile project(':circular_progress_bar')
    compile files('libs/mobilecore_V1.1.jar')
    compile files('libs/libAdapterSDKMoPub.jar')
    compile files('libs/adcolony.jar')
}

And my top-level build.gradle:

// Top-level build file where you can add configuration options common to all sub-projects/modules.

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:1.3.0'

        // NOTE: Do not place your application dependencies here; they belong
        // in the individual module build.gradle files
    }
}

allprojects {
    repositories {
        jcenter()
    }
}

I have tried with other version of gradle like 1.4.0-beta1', 1.4.0-beta2, and 1.3.1 still no luck.

Answer 1

this is a very easy problem to solve. the problem rises when you are developing an app and somewhere in the middle you update your SDK. this is fine but you what you don't know the gradle configuration for you project should be up to date. so simply create a new project and look at your classpath which for mine was com.android.tools.build:gradle:1.3.1 in the project but now new projects class path are classpath 'com.android.tools.build:gradle:1.5.0' . the other thing to consider is compileSdkVersion , buildToolsVersion , targetSdkVersion. you should also check if your libraries version are up to date. you can find their versions by simply opening you SDK-manager. so to wrap it up: this is what your project gradle should be updated:

buildscript {
    repositories {
        jcenter()
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:1.5.0' //update this section to the lates gradle core available
    }
}

and this is the sections in gradle module level file that should be updated:

android {
    compileSdkVersion 23 // update this one
    buildToolsVersion "23.0.2" // update this one

    defaultConfig {
        applicationId "ranjbar.hadi.something"
        minSdkVersion 14
        targetSdkVersion 23 // update this one
        versionCode 1
        versionName "1.0"
    }
    buildTypes {
        release {
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'),
                    'proguard-rules.pro'
        }
    }
}

hope this helps

Answer 2

There is some info right there in your trace --

Warning:there were 4 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)

At least part of your problem is that AndroidHttpClient was removed in API 23, and at least one of your libraries depends on it. You have three options.

1) You can include the following in your build.gradle file. Which includes the legacy library in your apk. See Apache HTTP Client Removal.

android {
    useLibrary 'org.apache.http.legacy'
}

2) You can lower your target and compile sdk to 22 instead of 23. That should allow you to compile, or at least resolve the AndroidHttpClient issue until the libraries are updated to not require it.

3) You can add -dontwarn commands to your proguard file to suppress the warns to get a build. As noted in the documentation, this can be dangerous if you aren't certain the warnings can be safely ignored. I am not certain if ignoring warnings stemming from the removal of HttpClient and associated classes is safe or not. It might lead to an unstable build when running on M, but should be safe for L and below because those classes exist on devices at that API level.

ADDED: For whoever struggles the same, keep in mind that you'll have to lower your builToolsVersion and com.android.support in the dependency to 22.0.1.