Using a Fragment inside my ArrayAdapter

Question

If I want to reuse a Fragment inside my ArrayAdapter, is that inefficient?

That is, in my ArrayAdapter, my getView() would look like this:

public View getView(final int position, View convertView, ViewGroup parent) {
        UserFragment userFragment = new UserFragment();
        return userFragment.getView();
}

I ask, because normally in the getView() method, it looks something like this:

public View getView(final int position, View convertView, ViewGroup parent) {
        View view = convertView;
        if (view == null) {
            LayoutInflater inflater = (LayoutInflater) getContext()
                    .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            view = inflater.inflate(R.layout.user, null);
            ...//do stuff
        }

Is it inefficient to create a Fragment each time the getView() is called?

Zhenghong Wang · Accepted Answer · 2013-10-04 07:58:26Z

2

First, Fragment has its own life cycle, like Activity's onCreate, onDestory, etc.
So if you do UserFragment userFragment = new UserFragment() in getView(), every time you scroll the ListView, a lot of different Fragment's instances will be created and scroll-out ones will be GC. This costs a lot.

Second, you are not reusing views. Each Fragment's instance has its own view structure, so userFragment.getView() will return a brand new View each time.

Basically, it is not recommended to use Fragment inside ListView. Use convertView is more efficient.

answered Oct 4, 2013 at 7:58

Zhenghong Wang

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Comments

gunar · Accepted Answer · 2013-10-04 07:19:58Z

A Fragment is managed by a FragmentManager (through FragmentTransactions) owned by an Activity. Or you can have Fragments in Fragments.

A ListView manages its own views separately and also is recycling these views so when you scroll you'll get in convertView the view that you should use.

Bottom-line is: fragments reside ONLY in activities or in other fragments, while Views (ListView is a descendant of View) stay in Fragments or in Activities.

So: Is it inefficient to create a Fragment each time the getView() is called?. I see no reason why you should do this. In fact, it would be 1000 times more helpful to make push-ups instead of using Fragments in Views. There is not a single good technical article where somebody discusses these.

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