Adapter that simply returns row views from a list. : ListActivity « UI « Android

1. Android
2. UI
3. ListActivity

Adapter that simply returns row views from a list.

   
//package pl.ppsoft.fixlang.common;

import java.util.ArrayList;
import java.util.List;

import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;

/**
 * Adapter that simply returns row views from a list.
 *
 * If you supply a size, you must implement newView(), to
 * create a required view. The adapter will then cache these
 * views.
 *
 * If you supply a list of views in the constructor, that
 * list will be used directly. If any elements in the list
 * are null, then newView() will be called just for those
 * slots.
 *
 * Subclasses may also wish to override areAllItemsEnabled()
 * (default: false) and isEnabled() (default: false), if some
 * of their rows should be selectable.
 *
 * It is assumed each view is unique, and therefore will not
 * get recycled.
 *
 * Note that this adapter is not designed for long lists. It
 * is more for screens that should behave like a list. This
 * is particularly useful if you combine this with other
 * adapters (e.g., SectionedAdapter) that might have an
 * arbitrary number of rows, so it all appears seamless.
 */
public class ListViewAdapter extends BaseAdapter {
  private List<View> views=null;

  /**
    * Constructor creating an empty list of views, but with
    * a specified count. Subclasses must override newView().
    */
  public ListViewAdapter(int count) {
    super();
    
    views=new ArrayList<View>(count);
    
    for (int i=0;i<count;i++) {
      views.add(null);
    }
  }

  /**
    * Constructor wrapping a supplied list of views.
    * Subclasses must override newView() if any of the elements
    * in the list are null.
    */
  public ListViewAdapter(List<View> views) {
    super();
    
    this.views=views;
  }

  /**
    * Get the data item associated with the specified
    * position in the data set.
    * @param position Position of the item whose data we want
    */
  @Override
  public Object getItem(int position) {
    return(views.get(position));
  }

  /**
    * How many items are in the data set represented by this
    * Adapter.
    */
  @Override
  public int getCount() {
    return(views.size());
  }

  /**
    * Returns the number of types of Views that will be
    * created by getView().
    */
  @Override
  public int getViewTypeCount() {
    return(getCount());
  }

  /**
    * Get the type of View that will be created by getView()
    * for the specified item.
    * @param position Position of the item whose data we want
    */
  @Override
  public int getItemViewType(int position) {
    return(position);
  }

  /**
    * Are all items in this ListAdapter enabled? If yes it
    * means all items are selectable and clickable.
    */
  @Override
  public boolean areAllItemsEnabled() {
    return(false);
  }

  /**
    * Returns true if the item at the specified position is
    * not a separator.
    * @param position Position of the item whose data we want
    */
  @Override
  public boolean isEnabled(int position) {
    return true;
  }

  /**
    * Get a View that displays the data at the specified
    * position in the data set.
    * @param position Position of the item whose data we want
    * @param convertView View to recycle, if not null
    * @param parent ViewGroup containing the returned View
    */
  @Override
  public View getView(int position, View convertView,
                      ViewGroup parent) {
    View result=views.get(position);
    
    if (result==null) {
      result=newView(position, parent);
      views.set(position, result);
    }
    
    return(result);
  }

  /**
    * Get the row id associated with the specified position
    * in the list.
    * @param position Position of the item whose data we want
    */
  @Override
  public long getItemId(int position) {
    return(position);
  }

  /**
    * Create a new View to go into the list at the specified
    * position.
    * @param position Position of the item whose data we want
    * @param parent ViewGroup containing the returned View
    */
  protected View newView(int position, ViewGroup parent) {
    throw new RuntimeException("You must override newView()!");
  }
}

   
    
    
  

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