android: problem with Serializable object put into intent

Question

Hi i have problem with a class i want to pass in an intent by putting it into the putExtras() Its serializable and the code looks like this:

public abstract class ObjectA extends ArrayList<ObjectA> implements java.io.Serializable{...}

public class ObjectB extends ObjectA {...}


...
Bundle extras = new Bundle();
extras.putSerializable("blabla", ObjectB);
intent.putExtras(extras);

...

Object y = getIntent().getExtras().get("blabla");

the problem is, that y now is an ArrayList and no longer an ObjectB so i cant cast it.. if i change the code to

public class ObjectB implements java.io.Serializable {...}

it works fine

Haulage

Just out of curiosity, what is "an intent" in this context? – Bildungsroman

ok i just added the android tag (again), an intent is an android internal thing – Haulage

Ah. Thanks! 15 characters! Woot! – Bildungsroman

ArrayLists don't implement Serializable, you can use a vector or write your own save and load functions for Serializable. – Latham

when i surround the obeject which extends arraylist with another object that just implements serial. than there is no problem, so i think the serialization of the arraylist works..? – Haulage

Answer 1

By implementing both java.util.List and java.io.Serializable in your class you've triggered this android bug.

Carolann

I think I stumbled on the same issue: if I stuff a LinkedList in a bundle via putSerializable, when I try to get it by getSerializable I receive an ArrayList. Isn't it? – Militarism

Yeah, it does seem to goof up LinkedLists in Serializables in multiple circumstances. – Brei

Bug from 2009, still here 3 years later :( – Touzle

Still here and its 2014 now :( – Chrysalid

Answer 2

I suspect what's happening is that since you aren't declaring ObjectB as serializable it's "falling back" to the most recent parent object that is. So when you put it in to the Bundle you aren't actually putting in ObjectB, but ObjectB cast back to ArrayList.

I think you're going to have to go with the second ("works fine") code.

Branch

i now surrounded the ObjectB with a class (wich implements serializable) that wich contains the ObjectB instance. i need objectB to be a child of objectA so i think this is ne best solution. and its just a little change at the code – Haulage

Why can't you just have ObjectB extend ObjectA and implement Serializable? – Branch

Answer 3

How are you declaring ObjectB before you pass it into the bundle? From what I understand of your question you are getting no error when you pass in the bundle, only when removing it. Try retreiving your ObjectB into an ObjectB type directly like this:

ObjectB y = (ObjectB) getIntent().getExtras().get("blabla");

Telamon

Answer 4

The ObjectA in ArrayList should implements the interface Parcelable. After that you can put your arraylists in the intent, and get them in another activity.

Keith