Proguard issue while using GSON

Question

I am using Gson in my application and for that, i am using some classes with name as same as the one in using Json. My application works well, But while writing proguard, application crashes, I guess some of the classes are shrinking. my error is :

java.lang.ClassCastException: com.google.gson.internal.StringMap cannot be cast to com.sample.package.GsonClass

Answer 1

You need to add these lines to your proguard so that gson class is kept while signing your app..

##---------------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


# 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.** { *; }

##---------------End: proguard configuration for Gson  ----------

Answer 2

Another reason is: before use

List<T> list = gson.fromJson(jsonString, type);

you should construct the correct typeToken, like this:

Type type = new TypeToken<List<T>>(){}.getType();
List<T> list = gson.fromJson(jsonString,type)