Android Parcelable - Write and read ArrayList< IA > when IA is a interface

Question

I have a interface IA and class B and C that implement them. Both B and C implement Parcelable as well.

Then I have the tricky part:

Class D has a ArrayList< IA >. I need this too insert both classes B and C in the arraylist. They share the same structure but the "IS-A" relation don't apply.

I need to pass D from one activity to another as a Parcel.

I've tried to write (ArrayList<IA>) in.readSerializable but I got a IOException. I know that if IA was not a interface the problem was easy, but I can't seem to find an easy solution for this.

Any ideas?

@SuppressWarnings("unchecked")
public D (Parcel in) {
    list = new ArrayList<IA>();
    (...)    
    list = (ArrayList<IA>) in.readSerializable 
    }

@SuppressWarnings("rawtypes")
public static final Parcelable.Creator CREATOR =
new Parcelable.Creator() {
    public D createFromParcel(Parcel in) {
        return new D(in);
    }

    public D[] newArray(int size) {
        return new D[size];
    }
};

public int describeContents() {
    return 0;
}

public void writeToParcel(Parcel dest, int flags) {
    (...)
    dest.writeList(list);
}

and D use in.readArrayList(list, Creator)? but which creator? — Pedro Bernardo, Mar 21 '13 at 09:58
Could you post any code with class D's Parcelable method's to take a look. — Brosa, Mar 21 '13 at 10:33
I've edited the question with the solution (don't have enough reputation yet). — Pedro Bernardo, Mar 21 '13 at 11:16
agreed with your solution, except this allows an implementation of IA that is not parcelable of serializable, hence crashing when you writeList. — njzk2, Mar 21 '13 at 12:29
hum I see where you are going. But extending parcelable on IA won't do the trick. Any suggestion? — Pedro Bernardo, Mar 21 '13 at 13:06
Here's a prime example why you use `Cat`s and `Dog`s in examples. Jesus Christ, who's supposed to read this alphabet mess. To the poor soul who stumbles here: https://medium.com/@kcoppock/writing-parcelable-lists-with-inheritance-a739c42c055c#.th7o37yq3 — Eugen Pechanec, Dec 28 '16 at 01:58

score 43 · Accepted Answer · answered Dec 10 '13 at 11:14

43

    @SuppressWarnings("unchecked")
public D (Parcel in) {
    list = new ArrayList<IA>();
    (...)    
    //ERROR -> list = (ArrayList<IA>) in.readSerializable 
    list = in.readArrayList(IA.class.getClassLoader());
}

@SuppressWarnings("rawtypes")
public static final Parcelable.Creator CREATOR =
new Parcelable.Creator() {
    public D createFromParcel(Parcel in) {
        return new D(in);
    }

    public D[] newArray(int size) {
        return new D[size];
    }
};

public int describeContents() {
    return 0;
}

public void writeToParcel(Parcel dest, int flags) {
    (...)
    dest.writeList(list);
}

answered Dec 10 '13 at 11:14

Pedro Bernardo

973
2
8
17

i have one problem i think you can help. I have ArrayList> which i want to write to parcel and then read it in next activity. Can you please guide how to do that ? – Gem May 15 '14 at 06:36
check this one http://stackoverflow.com/questions/13228714/set-arraylist-hashmap-string-object-value – Pedro Bernardo May 16 '14 at 13:03
2

How to make sure that the "unchecked" warnings are not there? (Except suppressing them) – Terry Aug 20 '19 at 01:33

score 1 · Answer 2 · answered Oct 13 '17 at 14:32

1

I recommend you to install "Android Parcelable code generator" plugin. After this you can generate writeToParcel function, constructor which reads from parcel and creator class only whith clicking Alt+Insert buttons.

answered Oct 13 '17 at 14:32

Axbor Axrorov

2,720
2
17
35

Android Parcelable - Write and read ArrayList< IA > when IA is a interface

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