When call initLoader in Fragment?

Question

I have pretty simple Fragment with ListView, CursorLoader and CursorAdapter. Everything is in single activity (just switching fragments). My problem is that onLoadFinished() is called in some situations twice based on where I put initLoader() call. Those situations are:

configuration change (rotating screen etc.)
replacing current fragment with another using FragmentTransaction and then returning back (popping backstack). In this case detail fragment of one list item.

When initLoader() is put in onCreateView(), onActivityCreated() (recommended in documentation) onLoadFinished() is called twice after configuration change. There is explanation why by Rudik Krasniynos. But onLoadFinished() is called only once when popping newer fragment from backstack.

When initLoader() is placed in onResume()/onStart() method situation from above is reversed. Two calls onLoadFinished() for popping backstack and one for configuration change.

So the question is where or how to init Loader without calling onLoadFinished() twice or what to check to not init Loader twice. Thanks!

Code for replacing fragment:

FragmentTransaction ft = fm.beginTransaction();
ft.replace(R.id.root_view, fragment, tag);
ft.addToBackStack(null);
ft.commit();

Code for CursorAdapter:

//onCreateView
MyCursorAdapter mAdapter = new MyCursorAdapter(getActivity(), null, 0);
mList.setAdapter(mAdapter);
//in other/same lifecycle callbacks
getLoaderManager().initLoader(ID, null, this);

I'm using support library v18.

score 4 · Answer 1 · answered Feb 04 '15 at 15:25

4

To avoid onLoadFinished to be called more than once init your loader in onResume.

answered Feb 04 '15 at 15:25

MineConsulting SRL

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As I mentioned above calling it in onResume() also cause double calling. – Warlock Aug 12 '16 at 10:07

score 1 · Answer 2 · answered Jul 15 '14 at 17:01

1

I call it in onCreate and as far as I know this is the best practice... I'm using it right now and all work perfectly.

@Override
    protected void onCreate(Bundle savedInstanceState)

                             .......

          getSupportLoaderManager().initLoader(LOADER_ID, null, this);

                             .......
}

answered Jul 15 '14 at 17:01

Yurets

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May not always be completely safe. See https://issuetracker.google.com/issues/37017632 – Paulo Jul 23 '17 at 04:29

AndroidCoolestRulest · Answer 3 · 2015-02-06T15:28:49.823

0

Call it in onActivityCreated(Bundle savedInstanceState) in your fragment

getLoaderManager().initLoader(LOADER_ID, new Bundle(), this);

edited Feb 06 '15 at 15:28

answered Feb 04 '15 at 15:18

AndroidCoolestRulest

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Why not use mentioned configChanges - http://stackoverflow.com/questions/7818717/why-not-use-always-androidconfigchanges-keyboardhiddenorientation – Warlock Feb 06 '15 at 11:22

score 0 · Answer 4 · answered Jul 15 '16 at 06:26

0

How about checking savedInstanceState before init the loader.

if (savedInstanceState == null)
    getLoaderManager().initLoader(LOADER_ID, null, this);

answered Jul 15 '16 at 06:26

Steve.NayLinAung

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score 0 · Answer 5 · answered May 02 '21 at 18:05

0

getLoaderManager is deprecated use LoaderManager.getInstance(this).initLoader(0,null,this);

instead

answered May 02 '21 at 18:05

Vivek

115
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13

When call initLoader in Fragment?

5 Answers5