When trying to use a EnumTypeAdapter with Proguard, it results in a AssertionError in Gson.getAdapter(). This error seems to be due to type information being lost... below is all the relevant source code:
The Exception:
03-18 13:27:12.905: ERROR/roboguice(12139): Throwable caught during background processing java.lang.AssertionError at com.google.gson.internal.bind.TypeAdapters$EnumTypeAdapter.<init>(Unknown Source) at com.google.gson.internal.bind.TypeAdapters$24.create(Unknown Source) at com.google.gson.Gson.getAdapter(Unknown Source) The EnumTypeAdapter being used:
public class OperationResultSerializer implements JsonDeserializer<OperationResult>, JsonSerializer<OperationResult> { @Override public OperationResult deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException { int value = json.getAsJsonPrimitive().getAsInt(); return OperationResult.values()[value]; } @Override public JsonElement serialize(OperationResult src, Type typeOfSrc, JsonSerializationContext context) { return new JsonPrimitive(src.ordinal()); } } How I am constructing my GSON object:
gson = new GsonBuilder() .registerTypeAdapter(Calendar.class, new WcfCalendarSerializer()) .registerTypeAdapter(OperationResult.class, new OperationResultSerializer()) .registerTypeAdapter(FieldName.class, new FieldNameSerializer()) .registerTypeAdapter(MealType.class, new MealTypeSerializer()) .create(); My ProGuard Config:
#-dontusemixedcaseclassnames: Necessary when building on windows where x.class and X.class is the same file -dontusemixedcaseclassnames -keepattributes *Annotation* -keepattributes Signature # Preserve the special static methods that are required in all enumeration classes. -keepclassmembers enum * { public static **[] values(); public static ** valueOf(java.lang.String); } -keep public class * extends android.app.Application -keep public class * extends android.app.Activity -keep public class * extends android.app.Service -keep public class * extends android.content.BroadcastReceiver -keep public class * extends android.content.ContentProvider -keep 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*(...); } -keep class com.google.inject.** { *; } -keep class javax.inject.** { *; } -keep class javax.annotation.** { *; } -keep class roboguice.** { *; } -keep class * extends android.preference.Preference { 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*(...); } # Gson specific classes -keep class sun.misc.Unsafe { *; } #-keep class com.google.gson.stream.** { *; } ###Action bar sherlock -keep class android.support.v4.app.** { *; } -keep interface android.support.v4.app.** { *; } -keep class com.actionbarsherlock.** { *; } -keep interface com.actionbarsherlock.** { *; } ###RoboGuice -keepclassmembers class * { @com.google.inject.Inject <init>(...); } -keepclassmembers class * { void *(**On*Event); } -keep public class roboguice.** -keep class com.google.inject.** -keep class com.google.gson.** {*;} #datacontract -keep public class com.ordering.datacontract.* -keepclassmembers class com.ordering.datacontract.* # LVL License binder class -keep class com.android.vending.licensing.ILicensingService -dontwarn -ignorewarnings As stated earlier, I suspect something is failing due to type information being lost - after digging into the GSON source code, this is the code that is called to resolve the EnumTypeAdapter... clearly the getEnumConstants is returning a Name that does not exist as a field of the type classOfT. But I am unsure how that is possible.
private static final class EnumTypeAdapter<T extends Enum<T>> extends TypeAdapter<T> { private final Map<String, T> nameToConstant = new HashMap<String, T>(); private final Map<T, String> constantToName = new HashMap<T, String>(); public EnumTypeAdapter(Class<T> classOfT) { try { for (T constant : classOfT.getEnumConstants()) { String name = constant.name(); SerializedName annotation = classOfT.getField(name).getAnnotation(SerializedName.class); if (annotation != null) { name = annotation.value(); } nameToConstant.put(name, constant); constantToName.put(constant, name); } } catch (NoSuchFieldException e) { throw new AssertionError(); } } public T read(JsonReader in) throws IOException { if (in.peek() == JsonToken.NULL) { in.nextNull(); return null; } return nameToConstant.get(in.nextString()); } public void write(JsonWriter out, T value) throws IOException { out.value(value == null ? null : constantToName.get(value)); } } I have searched all over for possible solutions but have not found much help. Maybe someone has run into this before and can point me in the right direction?