package android.support.v17.leanback.widget; import android.util.SparseArray; /** * An ObjectAdapter implemented with a {@link android.util.SparseArray}. * This class maintains an array of objects where each object is associated * with an integer key which determines its order relative to other objects. */ public class SparseArrayObjectAdapter extends ObjectAdapter { private SparseArray mItems = new SparseArray(); /** * Construct an adapter with the given {@link PresenterSelector}. */ public SparseArrayObjectAdapter(PresenterSelector presenterSelector) { super(presenterSelector); } /** * Construct an adapter with the given {@link Presenter}. */ public SparseArrayObjectAdapter(Presenter presenter) { super(presenter); } /** * Construct an adapter. */ public SparseArrayObjectAdapter() { super(); } @Override public int size() { return mItems.size(); } @Override public Object get(int position) { return mItems.valueAt(position); } /** * Returns the index for the given item in the adapter. * * @param item The item to find in the array. * @return Index of the item, or a negative value if not found. */ public int indexOf(Object item) { return mItems.indexOfValue(item); } /** * Returns the index for the given key in the adapter. * * @param key The key to find in the array. * @return Index of the item, or a negative value if not found. */ public int indexOf(int key) { return mItems.indexOfKey(key); } /** * Notify that the content of a range of items changed. Note that this is * not same as items being added or removed. * * @param positionStart The position of first item that has changed. * @param itemCount The count of how many items have changed. */ public void notifyArrayItemRangeChanged(int positionStart, int itemCount) { notifyItemRangeChanged(positionStart, itemCount); } /** * Sets the item for the given key. * * @param key The key associated with the item. * @param item The item associated with the key. */ public void set(int key, Object item) { int index = mItems.indexOfKey(key); if (index >= 0) { if (mItems.valueAt(index) != item) { mItems.setValueAt(index, item); notifyItemRangeChanged(index, 1); } } else { mItems.append(key, item); index = mItems.indexOfKey(key); notifyItemRangeInserted(index, 1); } } /** * Clears the given key and associated item from the adapter. * * @param key The key to be cleared. */ public void clear(int key) { int index = mItems.indexOfKey(key); if (index >= 0) { mItems.removeAt(index); notifyItemRangeRemoved(index, 1); } } /** * Removes all items from this adapter, leaving it empty. */ public void clear() { final int itemCount = mItems.size(); if (itemCount == 0) { return; } mItems.clear(); notifyItemRangeRemoved(0, itemCount); } /** * Returns the object for the given key, or null if no mapping for that key exists. */ public Object lookup(int key) { return mItems.get(key); } }