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

Question 1

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

Question 2

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".

Question 3

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());

Question 4

In my case it is fixed after upgrading support library to 23.2.1

Question 5

It's not Proguard related issue.. But when proguard and minify enable it's issue occurrence is always.

Problem is in sequence of writing and reading of object...sequence should be same, as it is like reading file.

You can use android studio plug in for make class as parcelable https://plugins.jetbrains.com/plugin/7332?pr=

Question 6

In my case my class don't added CREATOR filed when extending from another Parcelable parent.

public class Image implements Parcelable {
        protected Image(Parcel in) {
        }

        public static final Creator<Image> CREATOR = new Creator<Image>() {
            @Override
            public Image createFromParcel(Parcel in) {
                return new Image(in);
            }

            @Override
            public Image[] newArray(int size) {
                return new Image[size];
            }
        };

        @Override
        public int describeContents() {
            return 0;
        }

        @Override
        public void writeToParcel(Parcel dest, int flags) {
        }
}

public class ImageChild extends Image {
        protected ImageChild(Parcel in) {
            super(in);
        }


        @Override
        public int describeContents() {
            return 0;
        }

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

In ImageChild missing CREATOR field

Question 7

Just remove all parcelable methods and generate them again with valid sequence

Question 8

In my case it was caused by data size exceeding max limit of that can be put to Parcel which is about 1 MB.

Solution: optimize your Parcelable code to put as less data as possible (e.g. do not put Serializable objects to Parcel)

Question 9

Using Kotlin, the object 'Nota' has a Custom object 'CentroCusto' that contains only primitive properties.

class Nota(var id: Int? = null, var centroCusto: ArrayList<CentroCusto>? = null) : Parcelable {

constructor(source: Parcel) : this(
        source.readValue(Int::class.java.classLoader) as Int?,
        //Exception in below line -> Unmarshalling unknown type code 
        source.createTypedArrayList(CentroCusto.CREATOR) 
)

override fun describeContents() = 0

override fun writeToParcel(dest: Parcel, flags: Int) = with(dest) {
    writeValue(id)
    writeTypedList(centroCusto)
}

companion object {
    @JvmField
    val CREATOR: Parcelable.Creator<Nota> = object : Parcelable.Creator<Nota> {
        override fun createFromParcel(source: Parcel): Nota = Nota(source)
        override fun newArray(size: Int): Array<Nota?> = arrayOfNulls(size)
    }
}

The CentroCusto class:

class CentroCusto(var id: Int? = null, var descricao: String? = null, var aprovacaoDiretoria: Int? = null, var permiteMarcar: Boolean? = null) : Parcelable {

constructor(parcel: Parcel) : this(
        parcel.readValue(Int::class.java.classLoader) as? Int,
        parcel.readString(),
        parcel.readValue(Int::class.java.classLoader) as? Int,
        parcel.readValue(Boolean::class.java.classLoader) as? Boolean) {
}

override fun writeToParcel(parcel: Parcel, flags: Int) {
    parcel.writeValue(id)
    parcel.writeString(descricao)
    parcel.writeValue(aprovacaoDiretoria)
    parcel.writeValue(permiteMarcar)
}

override fun describeContents(): Int {
    return 0
}

companion object CREATOR : Parcelable.Creator<CentroCusto> {
    override fun createFromParcel(parcel: Parcel): CentroCusto {
        return CentroCusto(parcel)
    }

    override fun newArray(size: Int): Array<CentroCusto?> {
        return arrayOfNulls(size)
    }
}

}

Question 10

Just to add: this error can also happen, when using custom views and don't properly save/restore their states via onSaveInstanceState() and onRestoreInstanceState().

So if this error occurs, also check your custom views.

Question 11

Parent Model have parcelable and Child Model have parcelable then used below code works fine and not getting unmarshalling error

Parent Model

data class ParentModel(
    @SerializedName("post_id") val post_id: String? = "",
    @SerializedName("images") val images: ArrayList<ChildModel>? = null
) : Parcelable {
   constructor(parcel: Parcel) : this(
        parcel.readString(),
        parcel.createTypedArrayList(ChildModel.CREATOR)!!
   )

   override fun writeToParcel(parcel: Parcel, flags: Int) {
       parcel.writeString(post_id)
       parcel.writeTypedList(images)
   }

   override fun describeContents(): Int {
       return 0
   }

   companion object CREATOR : Parcelable.Creator<ParentModel> {
       override fun createFromParcel(parcel: Parcel): ParentModel{
           return ParentModel(parcel)
       }

       override fun newArray(size: Int): Array<ParentModel?> {
           return arrayOfNulls(size)
       }
   }
}

Child Model

data class ChildModel(
    @SerializedName("image_id") val image_id: String? = "",
    @SerializedName("image_url") val image_url: String? = ""
) : Parcelable {
    constructor(parcel: Parcel) : this(
        parcel.readString(),
        parcel.readString()
    )

    override fun writeToParcel(parcel: Parcel, flags: Int) {
        parcel.writeString(image_id)
        parcel.writeString(image_url)
    }

    override fun describeContents(): Int {
        return 0
    }

    companion object CREATOR : Parcelable.Creator<ChildModel> {
        override fun createFromParcel(parcel: Parcel): ChildModel{
            return ChildModel(parcel)
        }

        override fun newArray(size: Int): Array<ChildModel?> {
            return arrayOfNulls(size)
        }
    }
}