How to update listview whose data was queried from database through SimpleCursorAdapter?

Question

I want to show the items queried from database in the listview with SimpleCursorAdapter. For example, there may be 20,000 items in the database. I want to just load 100 items(_id : 1-100) queried instead of load all items, when scrolling in the end of listview, load another 100 items(_id : 101-200) queried, how to achieve it? Any suggestion is welcome, thanks.

Relative codes are as follows:

protected void onCreate(Bundle savedInstanceState) {
    mCursor = managedQuery(CONTENT_URI, PROJECTION, null, null, "_id DESC");
    mAdapter = new SimpleCursorAdapter(this,R.layout.list_content,  mCursor, keys,  values);
    setListAdapter(mAdapter);
}

In my defined listview, i want to load more items by query database.

public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) 
{
    int lastItem = firstVisibleItem + visibleItemCount - 1;

    if (mListAdapter != null) {
        if ((lastItem == mListAdapter.getCount()-1) && (mRefreshState != REFRESHING)) {
            mFooterView.setVisibility(View.VISIBLE);
            mRefreshState = REFRESHING;
            new Handler().postDelayed(new Runnable() {  
                public void run() {  
                    //execute the task ,  i want to load more items by query database
                    RefreshListView(LOADING_STORED_INFO);                                           
                }  
             }, DEFAULT_DELAY_TIMER);           
        }
    }
}

In the AsyncTask loading data, i do the query operation.

    protected Integer doInBackground(Integer... params)
    { 
        Uri uri = ContentUris.withAppendedId(CONTENT_URI, mCursor.getInt(0)-1);
        cursor = managedQuery(uri, PROJECTION, null, null, "_id DESC");
        return (0 == params[0]) ? 1 : 0;
    }

    @Override
    protected void onPostExecute(Integer result)
    {
        mAdapter.changeCursor(cursor);//is this OK?
        mAdapter.notifyDataSetChanged();
        /*
        if (1 == result)
        {
            mListView.setSelection(1);
        }
        else
        {
            mListView.setSelection(mCount-1);               
        }*/
        // Call onRefreshComplete when the list has been refreshed.
        mListView.onRefreshComplete(result); 
        super.onPostExecute(result);
    }

Relative codes are as follows:

breeze
– breeze

2012-01-15 13:00:05 +00:00
Commented Jan 15, 2012 at 13:00 — breeze
– breeze, Commented Jan 15, 2012 at 13:00

Francesco Vadicamo · Accepted Answer · 2012-01-15 18:02:41Z

2

Use the LIMIT statement in the SQL query in this way:

SELECT your_column FROM your_table ORDER BY your_order LIMIT limit_skip, limit_count

Then you can use a OnScrollListener to retrieve the index of the first visible cell and the number of visible cells so you can increment limit_skip and limit_count coherently.

Instead of the generic AsyncTask use a CursorLoader and implement LoaderManager.LoaderCallbacks<Cursor> as follow:

public Loader<Cursor> onCreateLoader(int id, Bundle args){
    String orderBy = "_id DESC"
    if(args != null){
        orderBy += " LIMIT " + args.getInt("LIMIT_SKIP") + "," + args.getInt("LIMIT_COUNT");
    }

    return new CursorLoader(this /*context*/, CONTENT_URI, PROJECTION, null, null, orderBy);
}

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

public void onLoaderReset(Loader<Cursor> loader){
    listAdapter.swapCursor(null);
}

Then, in onCreate(), pass null as cursor to new SimpleCursorAdapter() and create the CursorLoader in this way:

getLoaderManager().initLoader(0, null, this /*LoaderCallbacks<Cursor>*/);

Then, in onScroll(), reset everytime the loader in this way:

Bundle args = new Bundle();
args.putInt("LIMIT_SKIP", limit_skip_value);
args.putInt("LIMIT_COUNT", limit_count_value);
getLoaderManager().restartLoader(0, args, this /*LoaderCallbacks<Cursor>*/);

edited Jan 15, 2012 at 18:02

answered Jan 15, 2012 at 9:55

Francesco Vadicamo

5,54238 silver badges29 bronze badges

Sign up to request clarification or add additional context in comments.

6 Comments

breeze Over a year ago

I used ContentProvider's query function instead of ues sql query. my problem is that how to change cursor to ensure the count of listview items is increased when queried more items.I used changeCursor and notifyDataSetChanged function but there is no use.

Francesco Vadicamo Over a year ago

Please, edit your question and add your code so we can help you better.

Francesco Vadicamo Over a year ago

@breeze try it and let me know!

breeze Over a year ago

I got an error information when compile onCreateLoader. "Type mismatch: cannot convert from CursorLoader to Loader<Cursor>".But no error was found while compile the sample code LoaderThrottle.java

breeze Over a year ago

I find a class MergeCursors which can support help for my current problem.Thanks for your participation.

|

Collectives™ on Stack Overflow

How to update listview whose data was queried from database through SimpleCursorAdapter?

1 Answer 1

6 Comments

Your Answer

Linked

Hot Network Questions

Collectives™ on Stack Overflow

1 Answer 1

6 Comments

Your Answer

Sign up or log in

Post as a guest

Linked

Related