transformClassesAndResourcesWithProguardForRelease FAILED

I am trying to Build my Android application with Gradle in console. But getting below error about task ':app:transformClassesAndResourcesWithProguardForRelease':

build.gradle:

buildscript {
    repositories {
        jcenter()
        maven { url "https://jitpack.io" }
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:2.2.3'
        classpath 'com.google.gms:google-services:3.0.0'
    }
}

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

task clean(type: Delete) {
    delete rootProject.buildDir
}

app/build.gradle

apply plugin: 'com.android.application'

android {
    compileSdkVersion 24
    buildToolsVersion '24.0.2'
    defaultConfig {
        applicationId "com.XXX.XXX"
        minSdkVersion 14
        targetSdkVersion 24
        versionCode 1
        versionName "0.1.0"
        testInstrumentationRunner "android.support.test.runner.AndroidJUnitRunner"
        multiDexEnabled true
    }
    buildTypes {
        release {
            shrinkResources true
            minifyEnabled true
            proguardFiles getDefaultProguardFile('proguard-android.txt'),
                    'proguard-rules.pro'
        }
    }
}


dependencies {
    compile fileTree(include: ['*.jar'], dir: 'libs')
    androidTestCompile('com.android.support.test.espresso:espresso-core:2.2.2', {
        exclude group: 'com.android.support', module: 'support-annotations'
    })
    compile('com.squareup.retrofit2:retrofit:2.1.0') {
        exclude module: 'okhttp'
    }
    compile 'com.android.support:appcompat-v7:24.2.1'
    compile 'com.android.support:design:24.2.1'
    compile 'com.squareup.okhttp3:okhttp:3.4.1'
    compile 'com.squareup.retrofit2:converter-moshi:2.1.0'
    compile 'moe.banana:moshi-jsonapi:2.2.0'
    compile 'com.squareup.moshi:moshi-adapters:1.3.1'
    compile 'com.google.android.gms:play-services-maps:9.6.0'
    compile 'com.android.support:multidex:1.0.1'
    compile 'com.google.firebase:firebase-core:9.6.0'
    compile 'com.google.firebase:firebase-crash:9.6.0'
    testCompile 'junit:junit:4.12'
}

apply plugin: 'com.google.gms.google-services'

gradle-wrapper.properties

distributionBase=GRADLE_USER_HOME
distributionPath=wrapper/dists
distributionUrl=https\://services.gradle.org/distributions/gradle-3.3-all.zip
zipStoreBase=GRADLE_USER_HOME
zipStorePath=wrapper/dists

./gradlew build --stacktrace

This is the exception I am receiving:

org.gradle.api.tasks.TaskExecutionException: Execution failed for task
':app:transformClassesAndResourcesWithProguardForRelease'.

Try adding this code to your proGuard rules, it worked for me

-ignorewarnings
-keep class * {
    public private *;
}

The answer was posted here: https://stackoverflow.com/questions/41362386/execution-failed-for-task-apptransformclassesandresourceswithproguardforrelea

add this code to ..your-project/app/proguard-rules.pro

 -ignorewarnings

your signed apk will be generated successfully...

> Update : > > That's better to fix your warning messages using -dontwarn or -keep > keys on your proguard-rules.pro... Because if you use (maybe your libraries) java reflection in your code the application will be crashed...

It worked for me I also had to add following in a pro-gaurd.txt file

#### -- Picasso --
 -dontwarn com.squareup.picasso.**

 #### -- OkHttp --

 -dontwarn com.squareup.okhttp.internal.**

 #### -- Apache Commons --

 -dontwarn org.apache.commons.logging.**

     -ignorewarnings 
-keep class * {
public private protected *;
}

I have changed nothing just comment

// shrinkResources true
// minifyEnabled true

you don't want to change any proguard file I have already searched for this issue after 2days wasted

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

Please remove above mentioned code in your gradle. This worked for me. This is only for given problem.

got this issue due to warning from Android
See comment: https://github.com/flutter/flutter/issues/40218#issuecomment-531047713

add the following rule to /android/app/proguard-rules.pro:
-dontwarn android.**

Use this code in 'proguard-rules.pro' may be resolve.

-keep class * {
public private protected *;
}

or

-keep class * {*;}

• note : above commands ignore obfuscates

• can use this instead above for save obfuscates state

  -keepnames class * {*;}

In Android Studio click "Rebuild Project" in the "Build" menu.

I have struggled with proguard-rules.pro for quite some time and am by no means a pro here! I am posting my file to show that you should not -keep class * without any parameters as this turns off all obfuscation. You can however protect every class that extends from a certain class or any class that implements a certain interface. You can also protect any class that has a constructor having specific elements. Please note that I did not comment every single line as I am not 100% sure of what everything does - it's more like an educated guess. My project includes ksoap2 (okhttp3, okio, XmlPull) that's what many rules are for.

Maybe this can be a starting point for you - you still may need to put some additional rules for your classes in.

-android
-dontpreverify
-repackageclasses ''
-allowaccessmodification
-optimizations !code/simplification/arithmetic
-keepattributes *Annotation*
-renamesourcefileattribute SourceFile
-keepattributes SourceFile,LineNumberTable

-keep public class * extends android.app.Activity
-keepclasseswithmembers class * extends com.way4net.oner.lifa.plugin.ThemedFragment
-keepclasseswithmembers class * extends com.way4net.oner.lifa.plugin.ThemedActivity
-keep public class * extends android.app.Application
-keep public class * extends android.app.Service
-keep public class * extends android.content.BroadcastReceiver
-keep public class * extends android.content.ContentProvider
-keepattributes Signature #there were 1 classes trying to access generic signatures using reflection emfehlung von proguard selbst

-keep public class * extends android.view.View {
      public <init>(android.content.Context);
      public <init>(android.content.Context, android.util.AttributeSet);
      public <init>(android.content.Context, android.util.AttributeSet, int);
      public void set*(...);
}

-keepclasseswithmembers class * {
     public <init>(android.content.Context, android.util.AttributeSet);
 }

-keepclasseswithmembers class * {
    public <init>(android.content.Context, android.util.AttributeSet, int);
}

-keepclassmembers class * extends android.content.Context {
    public void *(android.view.View);
    public void *(android.view.MenuItem);
}

-keepclassmembers class * implements android.os.Parcelable {
    static ** CREATOR;
}

-keepclassmembers class **.R$* {
    public static <fields>;
}

-keepclassmembers class * {
    @android.webkit.JavascriptInterface <methods>;
}

-dontwarn okhttp3.**
-dontwarn okio.**
-dontwarn android.support.v4.**
#-dontwarn javax.annotation.**
#-dontwarn org.xmlpull.v1.**
-dontnote android.net.http.*
-dontnote org.apache.commons.codec.**
-dontnote org.apache.http.**
-dontnote okhttp3.**
-dontnote org.kobjects.util.**
-dontnote org.xmlpull.v1.**
-keep class okhttp3.** {
      *;
 }

-keep class org.xmlpull.v1.XmlSerializer {
    *;
}
-keep class org.xmlpull.v1.XmlPullParser{
    *;
}
-dontwarn org.xmlpull.v1.XmlPullParser

-keep class org.xmlpull.v1.XmlSerializer {
    *;
}
-dontwarn org.xmlpull.v1.XmlSerializer

-keep class org.kobjects.** { *; }
-keep class org.ksoap2.** { *; }
-keep class okio.** { *; }
-keep class org.kxml2.** { *; }
-keep class org.xmlpull.** { *; }

I got the same error message when I was trying to build release build in android after install react-native-firebase.

These are the steps I followed,

1. Do all the configurations they mention in the react-native-firebase documentation.

2. Build an android app using this command

   ./gradlew assembleRelease

3. Got this error message.

> FAILURE: Build failed with an exception. > > * What went wrong: Execution failed for task ':app:transformClassesAndResourcesWithProguardForRelease'. > > Job failed, see logs for details

Resolved this issue by changing this code line in android/app/build.gradle

minifyEnabled true

to this

minifyEnabled enableProguardInReleaseBuilds

This was the only change I did. It works for me.

add -ignorewarnings in your proguard file and keep only those class that you did not want to obfuscate. Some of the libraries suggest to keep some of their classes if you are using proguard rules. Visit your libraries for details

add this line to gradle properties

android.enableR8=true