How to run SQLite query asynchronously

Question

I'm trying to get all the contacts from my SQLite database.

Everything is working fine, I just want to make it asynchronous and not run in the main thread, to not influence the UI.

public List<contacts> getAllcontacts() {
    List<contacts> contactsl = new LinkedList<contacts>();

String query = "SELECT  * FROM contacts WHERE show is not 'NOTSIGNEDUP'"
        +" ORDER BY name COLLATE NOCASE;";

SQLiteDatabase db = this.getWritableDatabase();
Cursor cursor = db.rawQuery(query, null);

contacts contact = null;
if (cursor.moveToFirst()) {
    do {
        contact = new contacts();

        contact.setName(cursor.getString(1));
        contact.setNumero(cursor.getString(3));
        contact.setProfil(cursor.getString(2));
        contact.setShow(cursor.getString(5));
        contact.setBlocked(cursor.getString(4));
        contact.setObjectid(cursor.getString(6));
        contactsl.add(contact);
    } while (cursor.moveToNext());
}

return contactsl;
}

I'm calling this function from my activity :

  final sql s = sql.getInstance(getContext());


   if (ContactsList != null) {
       ContactsList.clear();
       ContactsList.addAll(list);
       ContactsList.addAll(s.getAllcontacts_());
       cAdapter.notifyDataSetChanged();
   }

Is there any way to make s.getAllcontacts() runs asyn

I made my Fragment like this :

public class ContactsFragment extends Fragment implements LoaderManager.LoaderCallbacks<List<contacts>> {
    private RecyclerView mRecyclerView;
    private LinearLayoutManager mLayoutManager;
    private ContactsAdapter cAdapter;
    private List<contacts> ContactsList;



    public ContactsFragment() {
        // Required empty public constructor
    }

    public void set(List<contacts> list) {
        final sql s = sql.getInstance(getContext());


       if (ContactsList != null) {
           ContactsList.clear();
           ContactsList.addAll(list);
           ContactsList.addAll(s.getAllcontacts_());
           cAdapter.notifyDataSetChanged();
       }



    }


    @Override
    public View onCreateView(LayoutInflater inflater, ViewGroup container,
                             Bundle savedInstanceState) {
        View view = inflater.inflate(R.layout.fragment_blank, container, false);
        return view;

    }

    @Override
    public void onActivityCreated(Bundle savedInstanceState) {
        super.onActivityCreated(savedInstanceState);



        View view = getView();
        if(view != null) {
            mRecyclerView = (RecyclerView) view.findViewById(R.id.contacts_recycler);
            mRecyclerView.setHasFixedSize(true);
            mLayoutManager = new LinearLayoutManager(view.getContext());
            mRecyclerView.setLayoutManager(mLayoutManager);
            final sql s = sql.getInstance(view.getContext());
            ContactsList = new ArrayList<contacts>();
            cAdapter = new ContactsAdapter(ContactsList, mRecyclerView);
            mRecyclerView.setAdapter(cAdapter);
            getLoaderManager().initLoader(0, null, this);

        }
    }


    @Override
    public android.support.v4.content.Loader<List<contacts>> onCreateLoader(int id, Bundle args) {
        return new AppListLoader(this.getContext());
    }

    @Override
    public void onLoadFinished(android.support.v4.content.Loader<List<contacts>> loader, List<contacts> data) {
        ContactsList.addAll(data);
        cAdapter.notifyDataSetChanged();
    }

    @Override
    public void onLoaderReset(android.support.v4.content.Loader<List<contacts>> loader) {

    }


    public static class AppListLoader extends AsyncTaskLoader<List<contacts>> {
        final sql s = sql.getInstance(getContext());
        public AppListLoader(Context context) {
            super(context);
        }

        @Override
        public List<contacts> loadInBackground() {
            return s.getAllcontacts();

        }

    }


}

Wrap it in an AsyncTask or a Thread, the same basic ways that you make anything else asynchronous. — CommonsWare
– CommonsWare, Commented Dec 20, 2015 at 20:18

Blackbelt · Accepted Answer · 2015-12-20 20:33:21Z

1

in addition to what @CommonsWare suggests, you could also use give to the AsyncTaskLoader a try. You could define

public static class AppListLoader extends AsyncTaskLoader<List<Contact>> {

and move your querying logic in loadInBackground().

Your Activity/Fragment will make then use of the LoaderManager. It will implement LoaderManager.LoaderCallbacks<List<Contact>> and onCreateLoader will return a new instance of your AsyncTaskLoader. The List<Contact> will be delivered as part of onLoadFinished

answered Dec 20, 2015 at 20:33

Blackbelt

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5 Comments

Blackbelt Over a year ago

OnCreatLoader is returnin null. It has to return new AppListLoader(getActivity());

Stranger B. Over a year ago

And how to call this function ??

Blackbelt Over a year ago

Override onActivityCreated and call getLoaderManager().initLoader(0, null, this); . the method will be callee automatically by the framework

Stranger B. Over a year ago

Nothing happens when calling, I updated my post wih the final Fragment code

Blackbelt Over a year ago

I think that the only thing missing is the implementation of deliverResult in the AsyncTaskLoader

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