android {
    buildTypes {
        release {
            minifyEnabled true //啟用代碼壓縮
            shrinkResources true //啟用資源壓縮
            proguardFiles getDefaultProguardFile(‘proguard-android.txt'),
                    'proguard-rules.pro'//混淆規則文件配置
        }
    }
}

這里需要特別注意：每次release新版編譯后，最好將這些文件加入git版本庫一起保存，因為每次Release編譯后這些文件都會被覆蓋。

10:47:34.635 [ERROR] [system.err] Warning: com.kennyc.view.MultiStateView$1: can't find referenced method 'com.kennyc.view.MultiStateView$ViewState[] values()' in program class com.kennyc.view.MultiStateView$ViewState
10:47:34.636 [ERROR] [system.err] Warning: com.kennyc.view.MultiStateView$1: can't find referenced field 'com.kennyc.view.MultiStateView$ViewState LOADING' in program class com.kennyc.view.MultiStateView$ViewState

-keep class com.kennyc.**

# 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
# 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.

-keepattributes *Annotation*
-keep public class com.google.vending.licensing.ILicensingService
-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 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*();
}

# We want to keep methods in Activity that could be used in the XML attribute onClick
-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);
}

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

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

# 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.**

# Understand the @Keep support annotation.
-keep class android.support.annotation.Keep

-keep @android.support.annotation.Keep class * {*;}

-keepclasseswithmembers class * {
    @android.support.annotation.Keep <methods>;
}

-keepclasseswithmembers class * {
    @android.support.annotation.Keep <fields>;
}

-keepclasseswithmembers class * {
    @android.support.annotation.Keep <init>(...);
}

##---------------Begin: proguard configuration for Twitter  ----------
-dontwarn com.squareup.okhttp.**
-dontwarn com.google.appengine.api.urlfetch.**
-dontwarn rx.**
-dontwarn retrofit.**
-keepattributes Signature
-keepattributes *Annotation*
-keep class com.squareup.okhttp.** { *; }
-keep interface com.squareup.okhttp.** { *; }
-keep class retrofit.** { *; }
-keepclasseswithmembers class * {
    @retrofit.http.* <methods>;
}
##---------------End: proguard configuration for Twitter  ----------

##---------------Begin: proguard configuration for Gson  ----------
# Gson uses generic type information stored in a class file when working with fields. Proguard
# removes such information by default, so configure it to keep all of it.
-keepattributes Signature

# For using GSON @Expose annotation
-keepattributes *Annotation*

# Gson specific classes
-keep class sun.misc.Unsafe { *; }
#-keep class com.google.gson.stream.** { *; }

# Application classes that will be serialized/deserialized over Gson
-keep class com.google.gson.examples.android.model.** { *; }

# Prevent proguard from stripping interface information from TypeAdapterFactory,
# JsonSerializer, JsonDeserializer instances (so they can be used in @JsonAdapter)
-keep class * implements com.google.gson.TypeAdapterFactory
-keep class * implements com.google.gson.JsonSerializer
-keep class * implements com.google.gson.JsonDeserializer
##---------------End: proguard configuration for Gson  ----------

##---------------Begin: proguard configuration for Glide  ----------
-keep public class * implements com.bumptech.glide.module.GlideModule
-keep public enum com.bumptech.glide.load.resource.bitmap.ImageHeaderParser$** {
  **[] $VALUES;
  public *;
}
##---------------End: proguard configuration for Glide  ----------

##---------------Begin: proguard configuration for EventBus  ----------
-keepattributes *Annotation*
-keepclassmembers class ** {
    @org.greenrobot.eventbus.Subscribe <methods>;
}
-keep enum org.greenrobot.eventbus.ThreadMode { *; }

# Only required if you use AsyncExecutor
#-keepclassmembers class * extends org.greenrobot.eventbus.util.ThrowableFailureEvent {
#    <init>(java.lang.Throwable);
#}
##---------------End: proguard configuration for EventBus  ----------

##---------------Begin: proguard configuration for Paper  ----------
#1.Keep data classes:
-keep class com.bloomsky.android.model.** { *; }
#2.alternatively you can implement Serializable for all your data classes and keep all of them using:
#-keep class * implements java.io.Serializable { *; }
##---------------End: proguard configuration for Paper  ----------

##---------------Begin: proguard configuration for retrofit2  ----------
# Platform calls Class.forName on types which do not exist on Android to determine platform.
-dontnote retrofit2.Platform
# Platform used when running on Java 8 VMs. Will not be used at runtime.
-dontwarn retrofit2.Platform$Java8
# Retain generic type information for use by reflection by converters and adapters.
-keepattributes Signature
# Retain declared checked exceptions for use by a Proxy instance.
-keepattributes Exceptions
##---------------End: proguard configuration for retrofit2  ----------

-assumenosideeffects class android.util.Log {  
    public static *** v(...);  
    public static *** i(...);  
    public static *** d(...);  
    public static *** w(...);  
    public static *** e(...);  
}