具有Proguard apk大小的Libgdx比没有的大

当我想将Proguard与libgdx一起使用时，apk的大小会比没有的大。没有它的话，它的大小是3.01MB，但是有了它，它的大小超过了5MB，classes.dex就像4MB。该应用程序包括Admob、Google Play服务Strough BaseGameUtils和Universal TweenEngine。我使用以下proguard文件：

# To enable ProGuard in your project, edit project.properties
# to define the proguard.config property as described in that file.
#
# Add project specific ProGuard rules here.
# By default, the flags in this file are appended to flags specified
# in ${sdk.dir}/tools/proguard/proguard-android.txt
# You can edit the include path and order by changing the ProGuard
# include property in project.properties.
#
# For more details, see
#   http://developer.android.com/guide/developing/tools/proguard.html

# Add any project specific keep options here:
-verbose

-dontwarn android.support.**
-dontwarn com.badlogic.gdx.backends.android.AndroidFragmentApplication
-dontwarn com.badlogic.gdx.utils.GdxBuild
-dontwarn com.badlogic.gdx.physics.box2d.utils.Box2DBuild
-dontwarn com.badlogic.gdx.jnigen.BuildTarget*

-keepclassmembers class com.badlogic.gdx.backends.android.AndroidInput* {
   <init>(com.badlogic.gdx.Application, android.content.Context, java.lang.Object,
            com.badlogic.gdx.backends.android.AndroidApplicationConfiguration);
}

-keepclassmembers class com.badlogic.gdx.physics.box2d.World {
   boolean contactFilter(long, long);
   void    beginContact(long);
   void    endContact(long);
   void    preSolve(long, long);
   void    postSolve(long, long);
   boolean reportFixture(long);
   float   reportRayFixture(long, float, float, float, float, float);
}

-keep class com.badlogic.** {*;}

-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;
}

---

真正地检查两个apk文件内容并进行比较。找出不同之处以及哪些文件夹/文件突然需要更多空间。我只看到classes.dex太大了，它比没有proguard的整个应用程序都大，但我不知道为什么。