AlphabetIndexer avec adaptateur personnalisé géré par LoaderManager

Je suis en train de mettre en œuvre AlphabetIndexer avec Adaptateur Personnalisé comme ce

AlphabetIndexer avec Adaptateur Personnalisé

Ma classe ContactsCursorAdapter s'étend SimpleCursorAdapter et met en œuvre SectionIndexer
et je suis en utilisant un LoaderManager à gérer ma carte du curseur de sorte que j'ai annulé la swapCursor() méthode comme la deuxième réponse à l'exemple ci-dessus indique.

public class ContactsCursorAdapter extends SimpleCursorAdapter 
    implements SectionIndexer{

    private LayoutInflater mInflater;
    private Context mContext; 

    private AlphabetIndexer mAlphaIndexer;

    public ContactsCursorAdapter(Context context, int layout, Cursor c,
        String[] from, int[] to) {
        super(context, layout, c, from, to);

        mInflater = LayoutInflater.from(context);
        mContext = context;
    }

    public View getView(final int position, View convertView, ViewGroup parent) {
        ...
    }

    @Override
    public int getPositionForSection(int section) {
        return mAlphaIndexer.getPositionForSection(section);
    }

    @Override
    public int getSectionForPosition(int position) {
        return mAlphaIndexer.getSectionForPosition(position);
    }

    @Override
    public Object[] getSections() {
        return mAlphaIndexer.getSections();
    }

    public Cursor swapCursor(Cursor c) {
        //Create our indexer
        if (c != null) {
            mAlphaIndexer = new AlphabetIndexer(c, c.getColumnIndex(ContactsContract.Contacts.DISPLAY_NAME),
                " ABCDEFGHIJKLMNOPQRSTUVWXYZ");
        }
        return super.swapCursor(c);
    }
}

Toutefois, cette erreur se produit si j'ai mis mon listview fastScrollEnabled = true

getListView().setFastScrollEnabled(true);

dans ma classe ContactsCursorLoaderListFragment qui s'étend ListFragment et met en œuvre LoaderManager.LoaderCallbacks .

Ici est la trace de la pile:

04-25 01:37:23.280: E/AndroidRuntime(711): FATAL EXCEPTION: main
04-25 01:37:23.280: E/AndroidRuntime(711): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.sendit/com.sendit.ContactManager}: java.lang.NullPointerException
04-25 01:37:23.280: E/AndroidRuntime(711):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1956)
04-25 01:37:23.280: E/AndroidRuntime(711):  at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1981)
04-25 01:37:23.280: E/AndroidRuntime(711):  at android.app.ActivityThread.access$600(ActivityThread.java:123)
04-25 01:37:23.280: E/AndroidRuntime(711):  at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1147)
04-25 01:37:23.280: E/AndroidRuntime(711):  at android.os.Handler.dispatchMessage(Handler.java:99)
04-25 01:37:23.280: E/AndroidRuntime(711):  at android.os.Looper.loop(Looper.java:137)
04-25 01:37:23.280: E/AndroidRuntime(711):  at android.app.ActivityThread.main(ActivityThread.java:4424)
04-25 01:37:23.280: E/AndroidRuntime(711):  at java.lang.reflect.Method.invokeNative(Native Method)
04-25 01:37:23.280: E/AndroidRuntime(711):  at java.lang.reflect.Method.invoke(Method.java:511)
04-25 01:37:23.280: E/AndroidRuntime(711):  at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
04-25 01:37:23.280: E/AndroidRuntime(711):  at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
04-25 01:37:23.280: E/AndroidRuntime(711):  at dalvik.system.NativeStart.main(Native Method)
04-25 01:37:23.280: E/AndroidRuntime(711): Caused by: java.lang.NullPointerException
04-25 01:37:23.280: E/AndroidRuntime(711):  at com.sendit.ContactsCursorAdapter.getSections(ContactsCursorAdapter.java:222)
04-25 01:37:23.280: E/AndroidRuntime(711):  at android.widget.FastScroller.getSectionsFromIndexer(FastScroller.java:507)
04-25 01:37:23.280: E/AndroidRuntime(711):  at android.widget.FastScroller.init(FastScroller.java:269)
04-25 01:37:23.280: E/AndroidRuntime(711):  at android.widget.FastScroller.<init>(FastScroller.java:155)
04-25 01:37:23.280: E/AndroidRuntime(711):  at android.widget.AbsListView.setFastScrollEnabled(AbsListView.java:1144)
04-25 01:37:23.280: E/AndroidRuntime(711):  at com.sendit.LoaderCursor$ContactsCursorLoaderListFragment.onActivityCreated(LoaderCursor.java:107)
04-25 01:37:23.280: E/AndroidRuntime(711):  at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:847)
04-25 01:37:23.280: E/AndroidRuntime(711):  at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1032)
04-25 01:37:23.280: E/AndroidRuntime(711):  at android.app.BackStackRecord.run(BackStackRecord.java:622)
04-25 01:37:23.280: E/AndroidRuntime(711):  at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1382)
04-25 01:37:23.280: E/AndroidRuntime(711):  at android.app.Activity.performStart(Activity.java:4474)
04-25 01:37:23.280: E/AndroidRuntime(711):  at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1929)
04-25 01:37:23.280: E/AndroidRuntime(711):  ... 11 more

après la setFastScrollEnabled() méthode est appelée, il appelle la coutume adaptateur getSections() méthode qui est l'endroit où il se bloque.

public class LoaderCursor extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
FragmentManager fm = getFragmentManager();
//Create the list fragment and add it as our sole content.
if (fm.findFragmentById(android.R.id.content) == null) {
ContactsCursorLoaderListFragment list = new ContactsCursorLoaderListFragment();
fm.beginTransaction().add(android.R.id.content, list).commit();
}
}
public static class ContactsCursorLoaderListFragment extends ListFragment
implements LoaderManager.LoaderCallbacks<Cursor> {
ContactsCursorAdapter mAdapter;
Cursor mCursor;
String mCurFilter;
@Override
public void onActivityCreated(Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
populateContactList();
//Prepare the loader. Either re-connect with an existing one,
//or start a new one.
getLoaderManager().initLoader(0, null, this);
ListView lv = getListView();
lv.setFastScrollEnabled(true);
//lv.setScrollingCacheEnabled(true);
lv.setDivider(getResources().getDrawable(R.drawable.list_divider));
}       
//These are the Contacts rows that we will retrieve.
final String[] CONTACTS_SUMMARY_PROJECTION = new String[] {
ContactsContract.Contacts._ID,
ContactsContract.Contacts.DISPLAY_NAME,
ContactsContract.Contacts.PHOTO_ID, };
public Loader<Cursor> onCreateLoader(int id, Bundle args) {
//This is called when a new Loader needs to be created. This
//sample only has one Loader, so we don't care about the ID.
//First, pick the base URI to use depending on whether we are
//currently filtering.
Uri baseUri;
if (mCurFilter != null) {
baseUri = Uri.withAppendedPath(ContactsContract.Contacts.CONTENT_FILTER_URI,Uri.encode(mCurFilter));
} else {
baseUri = ContactsContract.Contacts.CONTENT_URI;
}
//Now create and return a CursorLoader that will take care of
//creating a Cursor for the data being displayed.
String selection = "((" + ContactsContract.Contacts.DISPLAY_NAME + 
" NOTNULL) AND (" + ContactsContract.Contacts.HAS_PHONE_NUMBER + "=1) 
AND (" + ContactsContract.Contacts.DISPLAY_NAME + " != '' ))";
String sortOrder = ContactsContract.Contacts.DISPLAY_NAME
+ " COLLATE LOCALIZED ASC";
return new CursorLoader(getActivity(), baseUri,
CONTACTS_SUMMARY_PROJECTION, selection, null, sortOrder);
}
public void onLoadFinished(Loader<Cursor> loader, Cursor data) { 
//Swap the new cursor in.  (The framework will take care of closing the
//old cursor once we return.)
mAdapter.swapCursor(data);
}
public void onLoaderReset(Loader<Cursor> loader) {
//This is called when the last Cursor provided to onLoadFinished()
//above is about to be closed. We need to make sure we are no
//longer using it.
mAdapter.swapCursor(null);
}
/**
* Populate the contact list
*/
private void populateContactList() {
//start mappings
String[] from = new String[] { ContactsContract.Contacts.DISPLAY_NAME };
int[] to = new int[] { R.id.contactInfo };
//Create an empty adapter we will use to display the loaded data.
mAdapter = new ContactsCursorAdapter(getActivity().getApplicationContext(),    
R.layout.contact_manager, null, from, to);
setListAdapter(mAdapter);
}   
}
}

Et si je commente la setFastScrollEnabled() appel, il ne fait pas d'erreur, mais je ne vois pas le AlphabetIndexer de travail.

Ne ce besoin d'être mis en œuvre différemment parce que mon adaptateur personnalisé est défini dans un ListFragment et pas un ListActivity?

Quelqu'un aurait-il des suggestions sur la façon de faire tout cela fonctionne?

source d'informationauteur toobsco42