Question

I have an application that uses a service to create an ArrayList of custom objects (MyObject) every x seconds. I then want my Activity to obtain this ArrayList.

I’m currently planning on having the Service send a message to the Activity’s handler every time it finishes the query for the data. I want the message to the Handler to contain the ArrayList of MyObjects.

When building the method in the Activity to get this ArrayList out of the message, I noticed that I couldn’t.

If I tried

msg.getData().getParcelableArrayList("myObjects")

Then the method I was passing it to that expected an ArrayList wouldn’t accept it. If I tried casting the results:

(ArrayList<MyObject>)msg.getData().getParcelableArrayList("myObjects")

I received the error: Cannot cast from ArrayList<Parcelable> to ArrayList<MyObject>

MyObject implements Parcelable and I have successfully sent an ArrayList from my service to my activity by having my activity call a method on the service to retrieve it. I’m trying to go away from having my activity poll my service for this data, though.

1) How can I send an ArrayList inside the bundle in a message to handler?

2) Is there a different model I should be using to have my service update the data in my Activity that may or may not be visible? I always want the data in my activity to be the latest from the Service.

Answer 1

There is another model that should be used. Another question I asked provided the answer:

Suppress notifications from a service if activity is running

As for #1, you could get around it by just removing the generics from the ArrayList declarations and casting as appropriate where needed. I know this works because that’s what I did before refactoring based on the other question asked.