Write a sub class of Parcelable to another Parcel

Question

I have a class that implements Parcelable interface:

class A implements Parcelable {

}

I have another class B th

Answer 1

A better way to handle this that avoids reflexion would be to simply call the static creator in the target type like this:

this.amazingObject = AmazingObject.CREATOR.createFromParcel(in);

and write it to the Parcelable using this.amazingObject.writeToParcel(Parcel, int)

Internally, when calling readParcelable(ClassLoader) this happens:

public final  T readParcelable(ClassLoader loader) {
    Parcelable.Creator creator = readParcelableCreator(loader);
    if (creator == null) {
        return null;
    }
    if (creator instanceof Parcelable.ClassLoaderCreator) {
        return ((Parcelable.ClassLoaderCreator)creator).createFromParcel(this, loader);
    }
    return creator.createFromParcel(this);
}

As you can see the last call of that method is just calling the right Creator but inside readParcelableCreator there is a whole lot of reflexion that we can avoid by just calling it directly.

This utility calls may be useful:

import android.os.Parcel;
import android.os.Parcelable;

public class Parcels {

    public static void writeBoolean(Parcel dest, Boolean value) {
        dest.writeByte((byte) (value != null && value ? 1 : 0));
    }

    public static Boolean readBoolean(Parcel in){
        return in.readByte() != 0;
    }

    public static void writeParcelable(Parcel dest, int flags, Parcelable parcelable) {
        writeBoolean(dest, parcelable == null);
        if (parcelable != null) {
            parcelable.writeToParcel(dest, flags);
        }
    }

    public static  T readParcelable(Parcel in, Parcelable.Creator creator) {
        boolean isNull = readBoolean(in);
        return isNull ? null : creator.createFromParcel(in);
    }

}