Question

Kindly provide me a sample code which will contain the following:

1. ListView in which each list items will have an image icon loaded from an url & 2 textviews .
   The image is to be lazily loaded.
2. Pagination in Android where when the user scrolls vertically & go to the 20th item , a progress dialog will be displayed & in the background a call to the webeservice is made to fetch the next set of list items.

I have implemented the Lazy loading part but unable to implement the pagination code.
I got a suggestion to implement the EndlessWrapper class but I am unable to add the logic to the existing code for pagination.
Kindly provide the sample code/logic on how to implement the Pagination on the existing Customised ListView.

Here is the ListView code:

public class LazyListAdapter extends BaseAdapter implements Filterable,
            OnClickListener {
        int count = 0;
        private Activity activity;
        private String[] data;
        private LayoutInflater inflater = null;
        public ImageLoader imageLoader;
        public LazyListAdapter(Activity a, String[] d) {
            activity = a;
            data = d;
            inflater = (LayoutInflater) activity
            .getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            imageLoader = new ImageLoader(activity.getApplicationContext());
        }
        public int getCount() {
            return data.length;
        }
        public Object getItem(int position) {
            return position;
        }
        public long getItemId(int position) {
            return position;
        }
        public class ViewHolder {
            public TextView textTitle;
            public ImageView image;
            public ImageView addImage;
        }
        public View getView(final int position, View convertView,
                ViewGroup parent) {
            View vi = convertView;
            ViewHolder holder;
            if (vi == null) {
                vi = inflater.inflate(R.layout.list_videos_content, null);
                holder = new ViewHolder();
                holder.image = (ImageView) vi.findViewById(R.id.iconLine);
                holder.textTitle = (TextView) vi.findViewById(R.id.textLine);
                holder.addImage = (ImageView) vi.findViewById(R.id.buttonLine);
                vi.setTag(holder);
            } else
                holder = (ViewHolder) vi.getTag();
            String textStr =tempVec.elementAt(1)
            holder.textTitle.setText(textStr);
            // Icons bound to the rows.
            // Bind the data efficiently with the holder.
            holder.image.setTag(data[position]);
            holder.addImage.setImageResource(R.id.buttonLine);
            imageLoader.DisplayImage(data[position], activity, holder.image);
            return vi;
        }
    }

    public Filter getFilter() {
        // TODO Auto-generated method stub
        return null;
    }

    public void onClick(View v) {
        int i = v.getId();
        // TODO Auto-generated method stub
    }

Answer 1

i developed something like this, i have an ArrayAdapter wich one handles CustomClass instances, on the construct of the ArrayAdapter i have something like this:

//add pagination item
       if(list.getActualPage()<list.getTotalPages()){
            add("More...");
        }

later when user click on this item i do this:
(on my activity who extends ListActivity)

@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
    super.onListItemClick(l, v, position, id);
    if(getListAdapter().getItem(position) instanceof String){
        v.setEnabled(false);
        ((ProgressBar)v.findViewById(R.id.listItemMoreProgressBar)).setVisibility(View.VISIBLE);
        fetchMoreResults(position);
    }else{
        //launch item information
        Intent intent = new Intent();
        intent.setClass(ListItemActivity.this, ItemInfoActivity.class);
        startActivity(intent);
    }
}

and the method fetchMoreResults(position); execute a web service operation in a thread to retrieve next results…

when operations ends, use a handler to update the ListAdapter and call notifyDataSetChanged();

hope this help you…

add more code by your request

//ItemInfo has all the information i need

MyList list;
//list have a Vector with item information
//int actualPage
//int totalPages

//this is the ListAdapter, when construct them or dataset changes i call syncData with the new data, if there are more items, i add the More… string again, and again… at the bottom is the method who launch the fetchMoreResults method, who invoke a web service to retrive more items.

class ItemList extends ArrayAdapter {

    private Context ctx;
    private String moreText = "More...";

    public ItemList(Context context, int textViewResourceId, List<Object> objects) {
        super(context, textViewResourceId, objects);
        this.ctx = context;

        //add pagination item
        if(list.getPaginaActual()<list.getTotalPaginas()){
            add(moreText);
        }
    }

    //call this method when adding more info into the list
    public void syncData( List<ItemInfo> newData ){
        remove(moreText);
        for(Object o : newData){
            add(o);
        }
        if(list.getPaginaActual()<list.getTotalPaginas()){
            add(moreText);
        }
    }

    ItemViewHolder itemHolder;
    MoreItemsViewHolder moreItemsHolder;

    @Override
    public View getView(final int position, View convertView, ViewGroup parent) {
        LayoutInflater inflater = LayoutInflater.from(ctx);
        if( getItem(position) instanceof String ){
            moreItemsHolder = new MoreItemsViewHolder();
            if(convertView == null || convertView.getTag() instanceof ItemViewHolder){
                convertView = inflater.inflate(R.layout.list_item_more, parent, false);
            }
            moreItemsHolder.title = ((TextView)convertView.findViewById(R.id.listItemMoreFirstLine));
            moreItemsHolder.title.setText(getItem(position).toString());
            convertView.setTag(moreItemsHolder);
        }else{
            itemHolder = new ItemViewHolder();
            if(convertView == null || convertView.getTag() instanceof MoreItemsViewHolder){
                convertView = inflater.inflate(R.layout.lista_propiedades, parent, false);
                convertView.setTag(itemHolder);
            }
            itemHolder.title = ((TextView)convertView.findViewById(R.id.listItemFirstLine));
            itemHolder.description = ((TextView)convertView.findViewById(R.id.listItemSecondLine));
            itemHolder.title.setText( ((ItemInfo)getItem(position)).getTitulo() );
            itemHolder.description.setText( ((ItemInfo)getItem(position)).getDescripcion() );

        }
        return convertView;
    }

}

static class ItemViewHolder{
    TextView title;
    TextView description;
}

static class MoreItemsViewHolder{
    TextView title;
}






@Override
protected void onListItemClick(ListView l, View v, int position, long id) {
    super.onListItemClick(l, v, position, id);
    if(getListAdapter().getItem(position) instanceof String){
        v.setEnabled(false);
        ((ProgressBar)v.findViewById(R.id.listItemMoreProgressBar)).setVisibility(View.VISIBLE);
        fetchMoreResults(position);
    }else{
        //launch item info
        Intent intent = new Intent();
        intent.setClass(MyActivity.this, ItemInfoActivity.class);
        startActivity(intent);
    }
}