How to fix Unmarshalling unknown type code XXX at offset YYY in Android?

It's because of Proguard obfuscation - it processed Parcelable. solution: Proguard causing RuntimeException (Unmarshalling unknown type code) in Parcelable class

There's some rules for write and read parcelables.

1- Be careful about type mismatch. If you write int, don't try to read long etc.

2- Be careful about order of writes and reads. Objects must be at the same sort order when reading and writing.

Both of these can cause "Unmarshalling unknown type code".

If a type of List is added, it should be:

@Override
    public void writeToParcel(Parcel dest, int flags) {
        super.writeToParcel(dest, flags);
        dest.writeList(this.mList);

and unparcel it using the class type like this:

protected MyClass(Parcel in) {
        super(in);
        this.mList = new ArrayList<>();
        in.readList(this.mList, MyRequiredClass.class.getClassLoader());