SimpleCursorAdapter constructor throws NullpointerException

Question

public class EntryListActivity extends ListActivity 
implements LoaderCallbacks<Cursor>{
    private SimpleCursorAdapter curAdpt;

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

        setContentView(R.layout.activity_entry_list);

        //ListView lview= (ListView) this.findViewById(android.R.id.list);

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

        // For the cursor adapter, specify which  columns go into which views
        String[] fromColumns = {DiaryContract.EntryContract.COL_NAME_CONTENT};
        int[] toViews = {R.id.entry_content}; // The TextView in simple_list_item_1

        Uri entriesUri= Uri.parse("content://"+DiaryProviderContract.AUTHORITY + "/" + DiaryProviderContract.Entry.BASE_PATH) ;
       Cursor entryCursor= this.getContentResolver().query(entriesUri, null,  null, null, null);

       System.out.println("cursor" + entryCursor.getColumnCount());

       this.curAdpt = new SimpleCursorAdapter(this, android.R.layout.activity_list_item, entryCursor, fromColumns, toViews, (Integer) null);

        //lview.setAdapter(this.curAdpt);

        this.setListAdapter(this.curAdpt);

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.entry_list, menu);
        return true;
    }

    @Override
    public Loader<Cursor> onCreateLoader(int arg0, Bundle arg1) {
        // TODO Auto-generated method stub
        Uri entriesUri= Uri.parse("content://com.metizta.diary.provider/entries");

        return new CursorLoader(this, entriesUri,
                null, null, null, null);

    }
@Override
    public Loader<Cursor> onCreateLoader(int arg0, Bundle arg1) {
        // TODO Auto-generated method stub
        Uri entriesUri= Uri.parse("content://com.metizta.diary.provider/entries");

        return new CursorLoader(this, entriesUri,
                null, null, null, null);

    }

    @Override
    public void onLoadFinished(Loader<Cursor> arg0, Cursor arg1) {
        // TODO Auto-generated method stub

        this.curAdpt.swapCursor(arg1);


    }

    @Override
    public void onLoaderReset(Loader<Cursor> arg0) {
        // TODO Auto-generated method stub
        this.curAdpt.swapCursor(null);

    }
}

It throws nullPointerException in line

this.curAdpt = new SimpleCursorAdapter(this, android.R.layout.activity_list_item, entryCursor, fromColumns, toViews, (Integer) null);

I'm confused - is it in the constructor, or is it in deferencing the parameters? — Andy Turner, Mar 18 '15 at 13:08
possible duplicate of [What is a Null Pointer Exception, and how do I fix it?](http://stackoverflow.com/questions/218384/what-is-a-null-pointer-exception-and-how-do-i-fix-it) — Jens, Mar 18 '15 at 13:08
@fallenAngel because `NullPointerException`s like this are quite straightforward to diagnose. You just need to work out which of the things is `null`, which you can do with a debugger. — Andy Turner, Mar 18 '15 at 13:12
I do understand nullpointerexception. but I dont understand how `this.curAdpt = new SimpleCursorAdapter(this, android.R.layout.activity_list_item, entryCursor, fromColumns, toViews, (Integer) null);` can throw null pointer exception — varuog, Mar 18 '15 at 13:12
I'd guess something in this reference chain is null: `android.R.layout.activity_list_item`. — Andy Turner, Mar 18 '15 at 13:14
i love trolling :) ... here is example what is going on there http://ideone.com/jl7es8 — Selvin, Mar 18 '15 at 13:17
@fallenAngel just put there 0 if you don't wana any special flags — Selvin, Mar 18 '15 at 13:20

score 0 · Answer 1 · answered Mar 18 '15 at 13:26

0

I suppose the problem is in (Integer) null, you should use other constructor for SimpleCursorAdapter: public SimpleCursorAdapter (Context context, int layout, Cursor c, String[] from, int[] to)

answered Mar 18 '15 at 13:26

Sergey Yamshchikov

979
7
11

What do you mean? Is it not an answer? – Sergey Yamshchikov Mar 18 '15 at 14:39

Richard Strand · Answer 2 · 2015-03-20T15:52:18.697

The last parameter when creating the SimpleCursorAdapter should be an int. Instead of casting a null to an Integer you should pass a zero to indicate you are not setting any of the flags.

this.curAdpt = new SimpleCursorAdapter(this, android.R.layout.activity_list_item, entryCursor, fromColumns, toViews, 0);

The constructor without the flags is not recommended and is deprecated because is enables auto-requery which results in Cursor queries being performed on the application's UI thread.

SimpleCursorAdapter constructor throws NullpointerException

2 Answers2