InfiniteScrollListView

Simple infinite scrolling ListView for Android. For a technical explanation of how this works, refer to this blog post. Included is a working example that demonstrates how to use the API.

API

InfiniteScrollAdapter

public abstract class InfiniteScrollAdapter extends BaseAdapter {
    Collection getItems();
    void addItems(Collection items);
    Object getRealItem(int position);
    View getRealView(LayoutInflater inflater, int position, View convertView, ViewGroup parent);
    View getLoadingView(LayoutInflater inflater, ViewGroup parent);
}

• getItems() must expose the underlying data as a collection.
• addItems() takes in a collection and, depending on whether the collection is empty, either adds the items to the underlying data or sets the internal doneLoading flag to true. The implementation must also call notifyDataSetChanged() at the end of the method.
• getRealItem() returns the object represented by that position. You can assume the position is within the bounds of whatever collection you expose via getItems().
• getRealView() works just like getView() in a regular ListAdapter, returning a view for the particular position.
• getLoadingView() also works like a regular ListAdapter, but returns a view that indicates that data is being loaded in the background.

InfiniteScrollOnScrollListener

The implementation of OnScrollListener that detects whether the ListView is close to its end.

IInfiniteScrollListener

public interface IInfiniteScrollListener {
    public void endIsNear();
}

endIsNear() is called when the ListView reaches near the end of the list, and should initiate fetching of new data. Note this this will be called on every scroll that is near the end, which can be several dozens of times a second, so the implementation of this should set a flag once loading is started to prevent loading multiple times.

Example

The included example is a simple implementation. The application is a single activity that creates an InfiniteScrollListView and an implementation of the InfiniteScrollAdapter using an ArrayList of trivial objects. It populates the list with an amount of items that does not extend beyond the view port, causing the immediate retrieval of data. Data fetching is simulated via an AsyncTask with a sleep() delay. It will load a maximum of 40 items, then return an empty collection to signify that no more data is available.

NOTE: The example also includes additions to the library to demonstrate which items in the list are considered visible by the OnScrollListener. The additional code is commented as such. This allows you to get a good understanding of how onScroll() works.

License

The MIT License (MIT)

Copyright (c) 2014 Sanders DeNardi

Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.