Java clone item from one ArrayList into another?

Question

I'm trying to copy elements from one arrayList into another, I starting getting errors in my app and I think the problem is that I was doing shallow copies.

How can I add an item from one array into another doing a deep copy/clone?

This is how I was copying the elements up to now:

public ArrayList<ResolveInfo> myAppsArr = new ArrayList(); 
public ArrayList<ResolveInfo> allAppsArr = new ArrayList(); 

    myAppsArr.add(allAppsArr.get(0));

Are you nor sure? 'I think the problem is that I was doing shallow copies'. You should be sure before starting to make deep copies. — MrSmith42
– MrSmith42, Commented Jan 13, 2013 at 20:14

Sam · Accepted Answer · 2013-01-13 20:19:54Z

3

How can I add an item from one array into another doing a deep copy/clone?

ResolveInfo has a constructor that creates new duplicate object for you:

myAppsArr.add(new ResolveInfo(allAppsArr.get(0)));

It appears this constructor was only added in API 17, you can try the generic clone method:

myAppsArr.add(allAppsArr.get(0).clone()); // No promises, I haven't tested this myself

Or you can create a method that manually creates a new ResolveInfo object since all of the member data is public.

edited Jan 13, 2013 at 20:19

answered Jan 13, 2013 at 20:14

Sam

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Leonidos · Accepted Answer · 2013-01-13 20:37:00Z

2

The easiest and most reliable way to do this for all android versions is to serialize ResolveInfo to parcel and create new ResolveInfo instance from that parcel.

ResolveInfo r1 = new ResolveInfo();
Parcel p = Parcel.obtain();
r1.writeToParcel(p, 0);
ResolveInfo r2 = ResolveInfo.CREATOR.createFromParcel(p);

answered Jan 13, 2013 at 20:37

Leonidos

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