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androidparcelable

Extending a class that implements Parcelable

I have a class, we'll call it class A, that implements Parcelable.

I have a second class, we'll call it class B, that extends class A.

My question is:

How do I write class B's member variables to the Parcel and then write it's parent class's (ie: class A's) member variables to the Parcel (and, subsequently, read them in)?

Is there some nifty trick to not needing to rewrite class A's Parcel code? Or do I just need to rewrite the Parcel code in class A and add additional code for class B's member variables?

Solution

  • How do I write class B's member variables to the Parcel and then write it's parent class's (ie: class A's) member variables to the Parcel

    Class B overrides writeToParcel() from Class A, chaining to the superclass and also adding its own objects to the Parcel.

    (and, subsequently, read them in)?

    Class B implements public static final Parcelable.Creator<MyParcelable> CREATOR in such a way that it can let both classes read their stuff in. If you take the approach of creating a constructor on Class B that takes a Parcel as a constructor parameter, just chain to the superclass constructor (to let Class A do its work), then read Class B's data.

    The key will be to do them both in the same order. If you intend to let Class A read its data first, Class A must write its data first.

    Is there some nifty trick to not needing to rewrite class A's Parcel code?

    Inheritance and chaining to the superclass.