content: package com.rsen.dialog.address.wheel.adapter;
  
  import android.database.DataSetObserver;
  import android.view.View;
  import android.view.ViewGroup;
  
  /**
   * Wheel items adapter interface
   */
  public interface WheelViewAdapter {
  	/**
  	 * Gets items count
  	 * @return the count of wheel items
  	 */
  	public int getItemsCount();
  	
  	/**
  	 * Get a View that displays the data at the specified position in the data set
  	 * 
  	 * @param index the item index
  	 * @param convertView the old view to reuse if possible
  	 * @param parent the parent that this view will eventually be attached to
  	 * @return the wheel item View
  	 */
  	public View getItem(int index, View convertView, ViewGroup parent);
  
  	/**
  	 * Get a View that displays an empty wheel item placed before the first or after
  	 * the last wheel item.
  	 * 
  	 * @param convertView the old view to reuse if possible
       * @param parent the parent that this view will eventually be attached to
  	 * @return the empty item View
  	 */
  	public View getEmptyItem(View convertView, ViewGroup parent);
  	
  	/**
  	 * Register an observer that is called when changes happen to the data used by this adapter.
  	 * @param observer the observer to be registered
  	 */
  	public void registerDataSetObserver(DataSetObserver observer);
  	
  	/**
  	 * Unregister an observer that has previously been registered
  	 * @param observer the observer to be unregistered
  	 */
  	void unregisterDataSetObserver(DataSetObserver observer);
  }
  