getLoaderManager().initLoader() doesn't accept 'this' as argument though the class (ListFragment) implements LoaderManager.LoaderCallbacks

Question

I\'m having trouble following a guide on using SQLite in Android. I\'m using a ListFragment instead of a ListActivity(as in the example), so I have

Answer 1

I'm using ActionBarSherlock with my app and I as well was running into this issue and worked through all the steps discussed by others in this question. However I was continuing to have the same problem after trying all the suggested resolutions.

The method initLoader(int, Bundle, LoaderManager.LoaderCallbacks<D>) in the type LoaderManager is not applicable for the arguments (int, null, this)

The issue was I had fallen into expecting Eclipse to tell me when I was missing something and it was telling me that but not in the way I was used to. Typically Eclipse in other cases would tell me I'm missing the overrides to make something work but it's not directly saying that here. I finally picked up on the "LoaderManager.LoaderCallbacks" being the issue and realized I had no callbacks for it thus this error was actually a very valid error. Adding the basic overrides resolved my issue and allowed me to move forward.

// Creates a new loader after the initLoader () call
@Override
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
  // do work
  return null;
}

@Override
public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
  adapter.swapCursor(data);
}

@Override
public void onLoaderReset(Loader<Cursor> loader) {
  // data is not available anymore, delete reference
  adapter.swapCursor(null);
}

Answer 2

I got around this by using a SherlockListFragment (or you could use ListFragment, I suppose), but have it contained within a Activity. I first created a generic FragmentHolderActivity class that looks like this:

FragmentHolderActivity.java

public class FragmentHolderActivity extends SherlockFragmentActivity {

    public static final String FRAGMENT_LAYOUT_RESOURCE_ID = "fragment_layout_resource_id";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        Integer fragmentLayoutResourceId = getIntent().getIntExtra(FRAGMENT_LAYOUT_RESOURCE_ID, Integer.MAX_VALUE);
        Assert.assertNotSame(fragmentLayoutResourceId, Integer.MAX_VALUE);

        setContentView(fragmentLayoutResourceId);
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case android.R.id.home:
                finish();
                return false;
            default:
                return super.onOptionsItemSelected(item);
        }
    }

}

Then you need to create an XML file for your fragment.

your_list_fragment.xml

<?xml version="1.0" encoding="utf-8"?>
<fragment
    xmlns:android="http://schemas.android.com/apk/res/android"
    android:name="com.example.YourListFragment"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:id="@+id/fragment" />

And here's the code you use to start the fragment:

    Intent intent = new Intent();
    intent.setClass(this, FragmentHolderActivity.class);
    intent.putExtra(FragmentHolderActivity.FRAGMENT_LAYOUT_RESOURCE_ID, R.layout.your_list_fragment);
    startActivity(intent);

You just tell the FragmentHolderActivity to use the your_list_fragment layout, which in turn loads the YourListFragment.java

You can then use: getSherlockActivity().getSupportLoaderManager().initLoader(...) in YourListFragment.java

Not sure if this is the correct approach, but it keeps all my logic in Fragments, which is nice.

Answer 3

It's late but maybe help some one.
if you use loader maneger in fragment and you min api is below HONEYCOMB
you shuld use this imports

import android.support.v4.app.LoaderManager;
import android.support.v4.content.CursorLoader;
import android.support.v4.content.Loader;
import android.support.v4.widget.CursorAdapter;      
import android.support.v4.app.Fragment;

and for initiate loader use this code

getActivity().getSupportLoaderManager().initLoader(/loader stuff*/);

hope this help some one.

Answer 4

If you use API 28 or later, instead of getLoaderManager use:

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

Answer 5

Casting the third argument solved the problem in my case:

from

 getLoaderManager().initLoader(0, null, this);

to

 getLoaderManager().initLoader(0, null, (android.app.LoaderManager.LoaderCallbacks<Cursor>) this);

Note:

1. minSdk was 8 and i was using support library v4.
2. (android.support.v4.app.LoaderManager.LoaderCallbacks<Cursor>) this) did not work.
3. getSupportLoaderManager() or getSupportLoadManager() did not work.
4. This code was inside activity not fragment

Answer 6

In my case I had to have my Activity extend ActionBarActivity from the android.support.v7.app package. I was then able to use

getSupportLoaderManager().initLoader(0, null, this);