ObservableWebView.java

public class ObservableWebView extends WebView {
    public ObservableWebView(Context context) {
        this(context, null);
    }

    public ObservableWebView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public ObservableWebView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        isInEditMode();
    }

    public OnBottomReachedListener mOnBottomReachedListener = null;
    private int mMinDistance = 0;

    /**
     * Set the listener which will be called when the WebView is scrolled to within some
     * margin of the bottom.
     *
     * @param bottomReachedListener
     * @param allowedDifference
     */
    public void setOnBottomReachedListener(OnBottomReachedListener bottomReachedListener, int allowedDifference) {
        mOnBottomReachedListener = bottomReachedListener;
        mMinDistance = allowedDifference;
    }


    /**
     * Implement this interface if you want to be notified when the WebView has scrolled to the bottom.
     */
    public interface OnBottomReachedListener {
        void onBottomReached(View v);
    }

    @Override
    protected void onScrollChanged(int left, int top, int oldLeft, int oldTop) {
        if (mOnBottomReachedListener != null) {
            if ((getContentHeight() - (top + getHeight())) <= (getContentHeight() / 2)) {
                mOnBottomReachedListener.onBottomReached(this);
            }
        }
        super.onScrollChanged(left, top, oldLeft, oldTop);
    }

}