Android RecyclerView + CursorLoader + ContentProvider + “Load More”

[pratikbutani]

POSTED ON STACKOVERFLOW:

I have created one Activity in that I am implementing CursorLoader for load data from Database.

I have done that thing for all records of that Table but I want to load 30-30 records like Load More Functionality

I have tried to create query and its loading first 30 records but I cant able to understand how can I request for new records.

My Activity Code is Like:

public class ProductListActivity extends AppCompatActivity
        implements LoaderManager.LoaderCallbacks<Cursor> {

    /**
     * Records in list
     */
    int offset = 0;

    /**
     * For Current Activity *
     */
    Context mContext;

    /**
     * Activity Binding
     */
    ActivityProductListBinding activityProductListBinding;

    /**
     * Product Adapter
     */
    ProductListAdapter productListAdapter;

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

        /**
         * DataBinding with XML
         */
        activityProductListBinding = DataBindingUtil.setContentView(this, R.layout.activity_product_list);

        /**
         * Getting Context
         */
        mContext = getApplicationContext();

        /***
         * TOOLBAR Settings...
         */
        setSupportActionBar(activityProductListBinding.toolbar);
        activityProductListBinding.toolbarTitleTextview.setText(R.string.string_title_products);
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setDisplayShowTitleEnabled(false);

        final ActionBar ab = getSupportActionBar();
        if (ab != null)
            ab.setDisplayHomeAsUpEnabled(true);

        /**
         * RecyclerView Setup
         */
        GridLayoutManager manager = new GridLayoutManager(this, 2);
        activityProductListBinding.productListRecyclerView.setLayoutManager(manager);

        /**
         * First Time init Loader
         */
        getSupportLoaderManager().initLoader(1, null, this);
    }

    @Override
    public Loader<Cursor> onCreateLoader(int id, Bundle args) {
        final Uri CONTENT_URI = KOOPSContentProvider.CONTENT_URI_PRODUCT.buildUpon()
                .appendQueryParameter(KOOPSContentProvider.QUERY_PARAMETER_OFFSET,
                        String.valueOf(offset))
                .build();
        return new CursorLoader(this, CONTENT_URI ,null, null, null, null);
    }

    @Override
    public void onLoadFinished(Loader<Cursor> loader, Cursor data) {
        //When the loader has loaded some data (either initially, or the
        //datasource has changed and a new cursor is being provided),
        //Then we'll swap out the cursor in our recyclerview's adapter
        // and we'll create the adapter if necessary
        Log.d(LogUtils.TAG, "Cursor : " + data.getCount());
        if (productListAdapter == null) {
            productListAdapter = new ProductListAdapter(this, data);
            activityProductListBinding.productListRecyclerView.setAdapter(productListAdapter);
        }
    }

    @Override
    public void onLoaderReset(Loader<Cursor> loader) {
        //If the loader is reset, we need to clear out the
        //current cursor from the adapter.
        productListAdapter.reQuery(null);
    }
}

UPDATE:

I have added EndlessRecyclerViewScrollListener

activityProductListBinding.productListRecyclerView.addOnScrollListener(new EndlessRecyclerViewScrollListener(manager) {
            @Override
            public void onLoadMore(int page, int totalItemsCount) {
                // Triggered only when new data needs to be appended to the list
                // Add whatever code is needed to append new items to the bottom of the list
                offset = limit * page;
                /**
                 * Adding Bundle in Loader and then Call
                 */
                getSupportLoaderManager().initLoader(LOADER_ID, productQueryData, ProductListActivity.this);
            }
        });

I have tried to MergeCursor in adapter but getting error:

FATAL EXCEPTION: main
Process: com.kevalam.koopsv3, PID: 25021

java.lang.IllegalStateException: Observer android.database.MergeCursor$1@570f82d is already registered.
    at android.database.Observable.registerObserver(Observable.java:49)
    at android.database.AbstractCursor.registerDataSetObserver(AbstractCursor.java:358)
    at android.database.CursorWrapper.registerDataSetObserver(CursorWrapper.java:222)
    at android.database.MergeCursor.<init>(MergeCursor.java:50)
    at com.kevalam.koops.adapter.ProductListAdapter.mergeCursor(ProductListAdapter.java:71)
    at com.kevalam.koops.ui.ProductListActivity.onLoadFinished(ProductListActivity.java:161)
    at com.kevalam.koops.ui.ProductListActivity.onLoadFinished(ProductListActivity.java:38)

If anyone know please help, Thanks in advance.

[andviane]

We have implemented the Uncover library that should make infinite scrolling with RecyclerView somewhat less painful. Apache license, available form Maven Central. Maybe you could give it a try?