Android SDK (r20 ou superior)
Verifique o proguard.config predefinido referido em project.properties
proguard.config=${sdk.dir}/tools/proguard/proguard-android.txt
Mais informações: http://proguard.sourceforge.net/manual/examples.html#androidapplication
No Gradle:
buildTypes {
release {
minifyEnabled true
shrinkResources true
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
...
}
}
Aqui você pode verificar um arquivo proguard "padrão" que continuo atualizando: https://medium.com/code-procedure-and-rants/android-my-standard-proguard-ffeceaf65521
Android SDK (r19 ou inferior)
Você pode adicioná-lo ao default.properties. Eu tenho adicionado manualmente sem ter tido problemas até agora.
Se você adicionar a linha:
proguard.config=proguard.cfg
Como disse, ele só usará o ProGuard ao exportar aplicativo assinado (Android Tools => Export Signed Application)
Se você iniciar o projeto com o SDK antes do Android 2.3, o proguard.cfgarquivo não será criado (próximo a default.propertiescomo em 2.3>).
Para habilitar a criação automática dele, basta atualizar para o SDK do Android 2.3 e criar um novo projeto com as fontes existentes (que são as fontes do projeto que você possui atualmente).
Automagicamente, o proguard.cfgpreenchimento será criado.
Se ainda assim, você deseja criá-lo manualmente, é o que ele deve conter:
-dontusemixedcaseclassnames
-dontskipnonpubliclibraryclasses
-dontwarn android.support.**
-verbose
-dontoptimize
-dontpreverify
-keepattributes *Annotation*
-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 com.google.vending.licensing.ILicensingService
-keep public class com.android.vending.licensing.ILicensingService
-keep public class * extends android.support.v4.app.Fragment
-keep public class * extends android.app.Fragment
-keepclasseswithmembernames class * {
native <methods>;
}
-keepclasseswithmembernames class * {
public <init>(android.content.Context, android.util.AttributeSet);
}
-keepclasseswithmembernames class * {
public <init>(android.content.Context, android.util.AttributeSet, int);
}
-keepclassmembers public class * extends android.view.View {
void set*(***);
*** get*();
}
-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>;
}
Acho que respondi a todas as perguntas acima.
ATUALIZAÇÃO :
Uma explicação linha por linha:
#Use 5 step of optimization
#-optimizationpasses 5
#When not preverifing in a case-insensitive filing system, such as Windows. This tool will unpack your processed jars,(if using windows you should then use):
-dontusemixedcaseclassnames
#Specifies not to ignore non-public library classes. As of version 4.5, this is the default setting
-dontskipnonpubliclibraryclasses
# 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
-dontwarn android.support.**
#Specifies to write out some more information during processing. If the program terminates with an exception, this option will print out the entire stack trace, instead of just the exception message.
-verbose
#The -optimizations option disables some arithmetic simplifications that Dalvik 1.0 and 1.5 can't handle. Note that the Dalvik VM also can't handle aggressive overloading (of static fields).
#To understand or change this check http://proguard.sourceforge.net/index.html#/manual/optimizations.html
#-optimizations !code/simplification/arithmetic,!field/*,!class/merging/*
# Note that if you want to enable optimization, you cannot just
# include optimization flags in your own project configuration file;
# instead you will need to point to the
# "proguard-android-optimize.txt" file instead of this one from your
# project.properties file.
#To repackage classes on a single package
#-repackageclasses ''
#Uncomment if using annotations to keep them.
#-keepattributes *Annotation*
#Keep classes that are referenced on the AndroidManifest
-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.BackupAgentHelper
-keep public class * extends android.preference.Preference
-keep public class com.google.vending.licensing.ILicensingService
-keep public class com.android.vending.licensing.ILicensingService
#Compatibility library
-keep public class * extends android.support.v4.app.Fragment
-keep public class * extends android.app.Fragment
#To maintain custom components names that are used on layouts XML.
#Uncomment if having any problem with the approach below
#-keep public class custom.components.package.and.name.**
# keep setters in Views so that animations can still work.
# see http://proguard.sourceforge.net/manual/examples.html#beans
-keepclassmembers public class * extends android.view.View {
void set*(***);
*** get*();
}
#To remove debug logs:
-assumenosideeffects class android.util.Log {
public static *** d(...);
public static *** v(...);
public static *** w(...);
}
#To avoid changing names of methods invoked on layout's onClick.
# Uncomment and add specific method names if using onClick on layouts
#-keepclassmembers class * {
# public void onClickButton(android.view.View);
#}
#Maintain java native methods
-keepclasseswithmembernames class * {
native <methods>;
}
#To maintain custom components names that are used on layouts XML:
-keep public class * extends android.view.View {
public <init>(android.content.Context);
}
-keep public class * extends android.view.View {
public <init>(android.content.Context, android.util.AttributeSet);
}
-keep public class * extends android.view.View {
public <init>(android.content.Context, android.util.AttributeSet, int);
}
#Maintain enums
-keepclassmembers enum * {
public static **[] values();
public static ** valueOf(java.lang.String);
}
#To keep parcelable classes (to serialize - deserialize objects to sent through Intents)
-keep class * implements android.os.Parcelable {
public static final android.os.Parcelable$Creator *;
}
#Keep the R
-keepclassmembers class **.R$* {
public static <fields>;
}
###### ADDITIONAL OPTIONS NOT USED NORMALLY
#To keep callback calls. Uncomment if using any
#http://proguard.sourceforge.net/index.html#/manual/examples.html#callback
#-keep class mypackage.MyCallbackClass {
# void myCallbackMethod(java.lang.String);
#}
#Uncomment if using Serializable
#-keepclassmembers class * implements java.io.Serializable {
# private static final java.io.ObjectStreamField[] serialPersistentFields;
# private void writeObject(java.io.ObjectOutputStream);
# private void readObject(java.io.ObjectInputStream);
# java.lang.Object writeReplace();
# java.lang.Object readResolve();
#}
ATUALIZAÇÃO 2:
No ADT / Proguard mais recente, use em -keepclasseswithmembersvez de-keepclasseswithmembernames