我的节目：

-dontwarn retrofit2.**
-keep class retrofit2.** { *; }
-keepattributes Signature
-keepattributes Exceptions
-keepclassmembers class fqcn.of.javascript.interface.for.webview {
   public *;
}    

# Begin twitter 4j.
-dontwarn twitter4j.**
-keep  class twitter4j.conf.PropertyConfigurationFactory
-keep class twitter4j.** { *; }
# End twitter 4j.


# Start androidsocialnetworks
-keep class com.androidsocialnetworks.lib.** { *; }
# End androidsocialnetworks.

# Google api
-keep class com.google.** { *;}
-keep interface com.google.** { *;}
-dontwarn com.google.**

-dontwarn sun.misc.Unsafe
-dontwarn com.google.common.collect.MinMaxPriorityQueue
-keepattributes *Annotation*,Signature
-keep class * extends com.google.api.client.json.GenericJson {
*;
}
-keep class com.google.api.services.** {
*;
}

-dontwarn com.google.android.gms.cast.**
-dontwarn com.google.android.gms.**
-keep class com.google.android.gms.** { *; }

-keep class * extends java.util.ListResourceBundle {
    protected Object[][] getContents();
}

-keep public class com.google.android.gms.common.internal.safeparcel.SafeParcelable {
    public static final *** NULL;
}

-keepnames @com.google.android.gms.common.annotation.KeepName class *
-keepclassmembernames class * {
    @com.google.android.gms.common.annotation.KeepName *;
}

-keepnames class * implements android.os.Parcelable {
    public static final ** CREATOR;
}
# End google api

# Other
-optimizations !class/unBoxing/enum
-dontwarn com.google.code.**
-dontwarn oauth.signpost.**
-dontwarn javax.management.**
-dontwarn javax.xml.**
#-dontwarn org.apache.**
#-dontwarn org.slf4j.**
-keep class org.** { *; }
-keep class javax.** { *; }
-assumenosideeffects class * implements org.slf4j.Logger {
    public *** trace(...);
    public *** debug(...);
    public *** info(...);
    public *** warn(...);
    public *** error(...);
}

# Rx java
-dontwarn sun.misc.**
-keep class rx.internal.util.unsafe.** { *; }

-keepclassmembers class rx.internal.util.unsafe.*ArrayQueue*Field* {
   long producerIndex;
   long consumerIndex;
}

-keepclassmembers class rx.internal.util.unsafe.BaseLinkedQueueProducerNodeRef {
    rx.internal.util.atomic.LinkedQueueNode producerNode;
}

-keepclassmembers class rx.internal.util.unsafe.BaseLinkedQueueConsumerNodeRef {
    rx.internal.util.atomic.LinkedQueueNode consumerNode;
}

# End other


# Java mail
-dontwarn java.awt.**
-dontwarn java.beans.Beans
-dontwarn javax.security.**

-keep class javamail.** {*;}
-keep class javax.mail.** {*;}
-keep class javax.activation.** {*;}

-keep class com.sun.mail.dsn.** {*;}
-keep class com.sun.mail.handlers.** {*;}
-keep class com.sun.mail.smtp.** {*;}
-keep class com.sun.mail.util.** {*;}
-keep class mailcap.** {*;}
-keep class mimetypes.** {*;}
-keep class myjava.awt.datatransfer.** {*;}
-keep class org.apache.harmony.awt.** {*;}
-keep class org.apache.harmony.misc.** {*;}
# End java mail

在build.gradle中我还使用了一些proguard文件：
(我来自：https://github.com/krschultz/android-proguard-snippets)

proguardFile 'proguards/proguard-support-v7-appcompat.pro'
        proguardFile 'proguards/proguard-google-play-services.pro'
        proguardFile 'proguards/proguard-gson.pro'
        proguardFile 'proguards/proguard-butterknife-7.pro'
        proguardFile 'proguards/proguard-square-retrofit2.pro'
        proguardFile 'proguards/proguard-rx-java.pro'
        proguardFile 'proguards/proguard-rxjava-promises.pro'
        proguardFile 'proguards/proguard-square-okhttp3.pro'
        proguardFile 'proguards/proguard-jsoup.pro'
        proguardFile 'proguards/proguard-jackson-2.pro'
        proguardFile 'proguards/proguard-simple-xml.pro'
        proguardFile 'proguards/proguard-support-design.pro'
        proguardFile 'proguards/proguard-square-okio.pro'
        proguardFile 'proguards/proguard-facebook.pro'

这是一个定义API的方法：

@GET("app/authenticate")
    Observable<AuthenticationModel> authenticate(
            @Query("email") String email,@Query("password") String password
    );

然后在proguard之后我反编译APK文件然后我得到：

@GET("app/authenticate")
    rx.a<AuthenticationModel> a();

我不知道为什么所有参数都被删除了.
(注意：当前项目工作以及如果不使用proguard)
请帮忙 ！

UPDATE

主要问题：我使用了proguard-android-optimize
所以我应该添加(作为@EpicPandaForce答案)：

-keepclasseswithmembers class * {
    @retrofit2.http.* <methods>;
}