Example of use from Proguard, from Android Studio

build.gradle

buildscript {
    repositories {
        mavenCentral()
        maven {
            url 'https://oss.sonatype.org/content/repositories/snapshots/'
        }
    }
    dependencies {
        classpath 'com.android.tools.build:gradle:0.9.+'
        classpath 'com.squareup.gradle:gradle-android-test-plugin:0.9.1-SNAPSHOT'
    }
}
apply plugin: 'android'
apply plugin: 'android-test'

repositories {
    mavenCentral()
    maven {
        url 'https://oss.sonatype.org/content/repositories/snapshots/'
    }
}

android {
    compileSdkVersion 19
    buildToolsVersion "19.1.0"

    defaultConfig {
        minSdkVersion 9
        targetSdkVersion 19
    }

    signingConfigs {
        debug {
            storeFile file("debug.keystore")
        }

        release {
            storeFile file("project.keystore")
            storePassword "1234"
            keyAlias "Project"
            keyPassword "1234"
        }
    }

    buildTypes {
        release {
            debuggable false
            runProguard true
            signingConfig signingConfigs.release
            proguardFile getDefaultProguardFile('proguard-android-optimize.txt')
        }
    }

    productFlavors {
        defaultFlavor {
            proguardFile 'proguard-rules.txt'
        }
    }

    sourceSets {
        main {
            java.srcDirs = ['src/main/java', 'src-gen/main/java']
        }
        instrumentTest.setRoot('src/test')
    }
}

dependencies {

    compile 'com.actionbarsherlock:actionbarsherlock:4.4.0@aar'
    compile 'com.android.support:support-v4:19.1.+'
    compile 'de.greenrobot:greendao:1.3.7'
    compile 'com.google.android.gms:play-services:4.4.52'

    testCompile 'junit:junit:4.10'
    testCompile 'org.robolectric:robolectric:2.1.+'
    testCompile 'com.squareup:fest-android:1.0.+'

    instrumentTestCompile 'junit:junit:4.10'
    instrumentTestCompile 'org.robolectric:robolectric:2.1.+'
    instrumentTestCompile 'com.squareup:fest-android:1.0.+'
}

task wrapper(type: Wrapper) {
    gradleVersion = '1.8'
}

proguard-rules

####################################################################################################
####################################################################################################
####################################################################################################
######################################### PROGUARD #################################################
####################################################################################################
####################################################################################################
####################################################################################################

# This is a configuration file for ProGuard.
# http://proguard.sourceforge.net/index.html#manual/usage.html
-dontusemixedcaseclassnames
-dontskipnonpubliclibraryclasses
-verbose

# Optimization is turned off by default. Dex does not like code run
# through the ProGuard optimize and preverify steps (and performs some
# of these optimizations on its own).
#-dontoptimize
#-dontpreverify

# If you want to enable optimization, you should include the
# following:
-optimizations !code/simplification/arithmetic,!code/simplification/cast,!field/*,!class/merging/*
-optimizationpasses 5
-allowaccessmodification
#
# Note that you cannot just include these flags in your own
# configuration file; if you are including this file, optimization
# will be turned off. You'll need to either edit this file, or
# duplicate the contents of this file and remove the include of this
# file from your project's proguard.config path property.

-keep public class * extends android.app.Activity
-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
-keep public class * extends android.app.backup.BackupAgent
-keep public class * extends android.preference.Preference
-keep public class * extends android.support.v4.app.Fragment
-keep public class * extends android.support.v4.app.DialogFragment
-keep public class * extends com.actionbarsherlock.app.SherlockListFragment
-keep public class * extends com.actionbarsherlock.app.SherlockFragment
-keep public class * extends com.actionbarsherlock.app.SherlockFragmentActivity
-keep public class * extends android.app.Fragment
-keep public class com.android.vending.licensing.ILicensingService

# For native methods, see http://proguard.sourceforge.net/manual/examples.html#native
-keepclasseswithmembernames class * {
 native <methods>;
}

-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.app.Activity {
 public void *(android.view.View);
}

# For enumeration classes, see http://proguard.sourceforge.net/manual/examples.html#enumerations
-keepclassmembers enum * {
 public static **[] values();
 public static ** valueOf(java.lang.String);
}

-keep class * implements android.os.Parcelable {
 public static final android.os.Parcelable$Creator *;
}

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

-keep class android.support.v4.app.** { *; }
-keep interface android.support.v4.app.** { *; }
-keep class com.actionbarsherlock.** { *; }
-keep interface com.actionbarsherlock.** { *; }
# The support library contains references to newer platform versions.
# Don't warn about those in case this app is linking against an older
# platform version. We know about them, and they are safe.
-dontwarn android.support.**
-dontwarn com.google.ads.**