refactor proguard ant task

build.xml

@@ -125,25 +125,11 @@
 	<taskdef resource="proguard/ant/task.properties"
 	    classpath="tools/proguard.jar" />
 	<mkdir dir="${optimized.dir}" />
-	<proguard>
+	<proguard configuration="proguard.cfg">
 	    -injars ${out.classes.absolute.dir}:${external.libs.dir}:tools/scala-library.jar(!META-INF/MANIFEST.MF,!library.properties)
 	    -outjars ${out.absolute.dir}/classes.min.jar
 	    -libraryjars ${toString:android.target.classpath}
-	    -dontwarn scala.**
-	    -dontnote scala.**
-	    -dontobfuscate
-	    -dontpreverify
-	    -repackageclasses ''
-	    -allowaccessmodification
-	    -optimizations !code/simplification/arithmetic,!code/allocation/variable
-	    -keepattributes *Annotation*
 	    -printusage ${optimized.dir}/proguard.usage
-	    -keep public class * extends android.app.Activity
-	    -keep public class * extends android.app.Service
-	    -keep public interface scala.ScalaObject
-	    -dontskipnonpubliclibraryclasses
-	    -dontskipnonpubliclibraryclassmembers
-	    -allowaccessmodification
 	</proguard>
     </target>
 

proguard.cfg

@@ -0,0 +1,33 @@
+-dontwarn scala.**
+-dontnote scala.**
+-dontobfuscate
+-dontpreverify
+-repackageclasses ''
+-allowaccessmodification
+-optimizations !code/simplification/arithmetic,!code/allocation/variable
+-keepattributes *Annotation*
+-keep public class * extends android.app.Activity
+-keep public class * extends android.app.Service
+-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 * implements android.os.Parcelable {
+	static android.os.Parcelable$Creator CREATOR;
+}
+-keepclassmembers class **.R$* {
+	public static <fields>;
+}
+-keep public interface scala.ScalaObject
+-dontskipnonpubliclibraryclasses
+-dontskipnonpubliclibraryclassmembers
+-allowaccessmodification
+