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package fr.rolandl.carousel; /* w ww . j a v a 2 s . c o m*/ import android.annotation.SuppressLint; import android.content.Context; import android.database.DataSetObserver; import android.os.Handler; import android.os.Parcelable; import android.os.SystemClock; import android.util.AttributeSet; import android.util.SparseArray; import android.view.ContextMenu; import android.view.ContextMenu.ContextMenuInfo; import android.view.SoundEffectConstants; import android.view.View; import android.view.ViewGroup; import android.view.accessibility.AccessibilityEvent; import android.widget.Adapter; import android.widget.ListView; /** * @author Igor Kushnarev, Ludovic Roland * @since 2014.12.19 */ //Inspired by http://www.codeproject.com/Articles/146145/Android-D-Carousel public abstract class CarouselBaseAdapter<T extends Adapter> extends ViewGroup { /** * Extra menu information provided to the * {@link android.view.View.OnCreateContextMenuListener#onCreateContextMenu(ContextMenu, View, ContextMenuInfo) } callback when a context menu is * brought up for this CarouselAdapter. */ protected static class AdapterContextMenuInfo implements ContextMenu.ContextMenuInfo { public AdapterContextMenuInfo(View targetView, int position, long id) { this.targetView = targetView; this.position = position; this.id = id; } /** * The child view for which the context menu is being displayed. This will be one of the children of this CarouselAdapter. */ public View targetView; /** * The position in the adapter for which the context menu is being displayed. */ public int position; /** * The row id of the item for which the context menu is being displayed. */ public long id; } protected class AdapterDataSetObserver extends DataSetObserver { private Parcelable mInstanceState = null; @Override public void onChanged() { dataChanged = true; oldItemCount = itemCount; itemCount = getAdapter().getCount(); // Detect the case where a cursor that was previously invalidated has // been repopulated with new data. if (CarouselBaseAdapter.this.getAdapter().hasStableIds() == true && mInstanceState != null && oldItemCount == 0 && itemCount > 0) { CarouselBaseAdapter.this.onRestoreInstanceState(mInstanceState); mInstanceState = null; } else { rememberSyncState(); } checkFocus(); requestLayout(); } @Override public void onInvalidated() { dataChanged = true; if (CarouselBaseAdapter.this.getAdapter().hasStableIds() == true) { // Remember the current state for the case where our hosting activity is being // stopped and later restarted mInstanceState = CarouselBaseAdapter.this.onSaveInstanceState(); } // Data is invalid so we should reset our state oldItemCount = itemCount; itemCount = 0; selectedPosition = CarouselBaseAdapter.INVALID_POSITION; selectedRowId = CarouselBaseAdapter.INVALID_ROW_ID; nextSelectedPosition = CarouselBaseAdapter.INVALID_POSITION; nextSelectedRowId = CarouselBaseAdapter.INVALID_ROW_ID; needSync = false; checkSelectionChanged(); checkFocus(); requestLayout(); } public void clearSavedState() { mInstanceState = null; } } private class SelectionNotifier extends Handler implements Runnable { @Override public void run() { if (dataChanged == true) { // Data has changed between when this SelectionNotifier // was posted and now. We need to wait until the CarouselAdapter // has been synched to the new data. post(this); } else { fireOnSelected(); } } } /** * Interface definition for a callback to be invoked when an item in this CarouselAdapter has been clicked. */ public static interface OnItemClickListener { /** * Callback method to be invoked when an item in this CarouselAdapter has been clicked. * <p/> * Implementers can call getItemAtPosition(position) if they need to access the data associated with the selected item. * * @param parent The CarouselAdapter where the click happened. * @param view The view within the CarouselAdapter that was clicked (this will be a view provided by the adapter) * @param position The position of the view in the adapter. * @param id The row id of the item that was clicked. */ public void onItemClick(CarouselBaseAdapter<?> parent, View view, int position, long id); } /** * Interface definition for a callback to be invoked when an item in this view has been clicked and held. */ public static interface OnItemLongClickListener { /** * Callback method to be invoked when an item in this view has been clicked and held. * <p/> * Implementers can call getItemAtPosition(position) if they need to access the data associated with the selected item. * * @param parent The AbsListView where the click happened * @param view The view within the AbsListView that was clicked * @param position The position of the view in the list * @param id The row id of the item that was clicked * @return true if the callback consumed the long click, false otherwise */ public boolean onItemLongClick(CarouselBaseAdapter<?> parent, View view, int position, long id); } /** * Interface definition for a callback to be invoked when an item in this view has been selected. */ public static interface OnItemSelectedListener { /** * Callback method to be invoked when an item in this view has been selected. * <p/> * Implementers can call getItemAtPosition(position) if they need to access the data associated with the selected item. * * @param parent The CarouselAdapter where the selection happened * @param view The view within the CarouselAdapter that was clicked * @param position The position of the view in the adapter * @param id The row id of the item that is selected */ public void onItemSelected(CarouselBaseAdapter<?> parent, View view, int position, long id); /** * Callback method to be invoked when the selection disappears from this view. The selection can disappear for instance when touch is activated or * when the adapter becomes empty. * * @param parent The CarouselAdapter that now contains no selected item. */ public void onNothingSelected(CarouselBaseAdapter<?> parent); } /** * Represents an invalid position. All valid positions are in the range 0 to 1 less than the number of items in the current adapter. */ public static final int INVALID_POSITION = -1; /** * Represents an empty or invalid row id */ public static final long INVALID_ROW_ID = Long.MIN_VALUE; /** * Sync based on the selected child */ protected static final int SYNC_SELECTED_POSITION = 0; /** * Sync based on the first child displayed */ private static final int SYNC_FIRST_POSITION = 1; /** * Maximum amount of time to spend in {@link #findSyncPosition()} */ private static final int SYNC_MAX_DURATION_MILLIS = 100; /** * The position of the first child displayed */ protected int firstPosition = 0; /** * Position from which to start looking for syncRowId */ protected int syncPosition; /** * Row id to look for when data has changed */ protected long syncRowId = CarouselBaseAdapter.INVALID_ROW_ID; /** * True if we need to sync to syncRowId */ protected boolean needSync = false; /** * Indicates whether to sync based on the selection or position. Possible values are {@link #SYNC_SELECTED_POSITION} or {@link #SYNC_FIRST_POSITION} * . */ protected int syncMode; /** * Indicates that this view is currently being laid out. */ protected boolean isInLayout = false; /** * The listener that receives notifications when an item is selected. */ private OnItemSelectedListener onItemSelectedListener; /** * The listener that receives notifications when an item is clicked. */ private OnItemClickListener onItemClickListener; /** * The listener that receives notifications when an item is long clicked. */ protected OnItemLongClickListener onItemLongClickListener; /** * True if the data has changed since the last layout */ protected boolean dataChanged; /** * The position within the adapter's data set of the item to select during the next layout. */ protected int nextSelectedPosition = CarouselBaseAdapter.INVALID_POSITION; /** * The item id of the item to select during the next layout. */ private long nextSelectedRowId = CarouselBaseAdapter.INVALID_ROW_ID; /** * The position within the adapter's data set of the currently selected item. */ protected int selectedPosition = CarouselBaseAdapter.INVALID_POSITION; /** * The item id of the currently selected item. */ protected long selectedRowId = CarouselBaseAdapter.INVALID_ROW_ID; /** * View to show if there are no items to show. */ private View emptyView; /** * The number of items in the current adapter. */ protected int itemCount; /** * The number of items in the adapter before a data changed event occured. */ protected int oldItemCount; /** * The last selected position we used when notifying */ protected int oldSelectedPosition = CarouselBaseAdapter.INVALID_POSITION; /** * The id of the last selected position we used when notifying */ protected long oldSelectedRowId = CarouselBaseAdapter.INVALID_ROW_ID; /** * Indicates what focusable state is requested when calling setFocusable(). In addition to this, this view has other criteria for actually * determining the focusable state (such as whether its empty or the text filter is shown). * * @see #setFocusable(boolean) * @see #checkFocus() */ private boolean desiredFocusableState; private boolean desiredFocusableInTouchModeState; private SelectionNotifier selectionNotifier; /** * When set to true, calls to requestLayout() will not propagate up the parent hierarchy. This is used to layout the children during a layout pass. */ private boolean blockLayoutRequests = false; public CarouselBaseAdapter(Context context) { super(context); } public CarouselBaseAdapter(Context context, AttributeSet attrs) { super(context, attrs); } public CarouselBaseAdapter(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); } /** * Register a callback to be invoked when an item in this CarouselAdapter has been clicked. * * @param listener The callback that will be invoked. */ public void setOnItemClickListener(OnItemClickListener listener) { onItemClickListener = listener; } /** * @return The callback to be invoked with an item in this CarouselAdapter has been clicked, or null id no callback has been set. */ public final OnItemClickListener getOnItemClickListener() { return onItemClickListener; } /** * Call the OnItemClickListener, if it is defined. * * @param view The view within the CarouselAdapter that was clicked. * @param position The position of the view in the adapter. * @param id The row id of the item that was clicked. * @return True if there was an assigned OnItemClickListener that was called, false otherwise is returned. */ public boolean performItemClick(View view, int position, long id) { if (onItemClickListener != null) { playSoundEffect(SoundEffectConstants.CLICK); onItemClickListener.onItemClick(this, view, position, id); return true; } return false; } /** * Register a callback to be invoked when an item in this CarouselAdapter has been clicked and held * * @param listener The callback that will run */ public void setOnItemLongClickListener(OnItemLongClickListener listener) { if (!isLongClickable()) { setLongClickable(true); } onItemLongClickListener = listener; } /** * @return The callback to be invoked with an item in this CarouselAdapter has been clicked and held, or null id no callback as been set. */ public final OnItemLongClickListener getOnItemLongClickListener() { return onItemLongClickListener; } /** * Register a callback to be invoked when an item in this CarouselAdapter has been selected. * * @param listener The callback that will run */ public void setOnItemSelectedListener(OnItemSelectedListener listener) { onItemSelectedListener = listener; } public final OnItemSelectedListener getOnItemSelectedListener() { return onItemSelectedListener; } /** * Return the position of the currently selected item within the adapter's data set * * @return int Position (starting at 0), or {@link #INVALID_POSITION} if there is nothing selected. */ public int getSelectedItemPosition() { return nextSelectedPosition; } /** * @return The id corresponding to the currently selected item, or {@link #INVALID_ROW_ID} if nothing is selected. */ public long getSelectedItemId() { return nextSelectedRowId; } /** * @return The data corresponding to the currently selected item, or null if there is nothing selected. */ public Object getSelectedItem() { T adapter = getAdapter(); int selection = getSelectedItemPosition(); if (adapter != null && adapter.getCount() > 0 && selection >= 0) { return adapter.getItem(selection); } else { return null; } } /** * @return The number of items owned by the Adapter associated with this CarouselAdapter. (This is the number of data items, which may be larger * than the number of visible view.) */ public int getCount() { return itemCount; } /** * Get the position within the adapter's data set for the view, where view is a an adapter item or a descendant of an adapter item. * * @param view an adapter item, or a descendant of an adapter item. This must be visible in this CarouselAdapter at the time of the call. * @return the position within the adapter's data set of the view, or {@link #INVALID_POSITION} if the view does not correspond to a list item (or * it is not currently visible). */ public int getPositionForView(View view) { View listItem = view; try { View v; while (!(v = (View) listItem.getParent()).equals(this)) { listItem = v; } } catch (ClassCastException exception) { // We made it up to the window without find this list view return INVALID_POSITION; } // Search the children for the list item final int childCount = getChildCount(); for (int i = 0; i < childCount; i++) { if (getChildAt(i).equals(listItem) == true) { return firstPosition + i; } } // Child not found! return INVALID_POSITION; } /** * Returns the position within the adapter's data set for the first item displayed on screen. * * @return The position within the adapter's data set */ public int getFirstVisiblePosition() { return firstPosition; } /** * Returns the position within the adapter's data set for the last item displayed on screen. * * @return The position within the adapter's data set */ public int getLastVisiblePosition() { return firstPosition + getChildCount() - 1; } /** * Sets the view to show if the adapter is empty */ public void setEmptyView(View emptyView) { this.emptyView = emptyView; final T adapter = getAdapter(); final boolean empty = ((adapter == null) || adapter.isEmpty()); updateEmptyStatus(empty); } /** * When the current adapter is empty, the CarouselAdapter can display a special view call the empty view. The empty view is used to provide feedback * to the user that no data is available in this CarouselAdapter. * * @return The view to show if the adapter is empty. */ public View getEmptyView() { return emptyView; } /** * Indicates whether this view is in filter mode. Filter mode can for instance be enabled by a user when typing on the keyboard. * * @return True if the view is in filter mode, false otherwise. */ private boolean isInFilterMode() { return false; } protected void checkFocus() { final T adapter = getAdapter(); final boolean empty = adapter == null || adapter.getCount() == 0; final boolean focusable = empty == false || isInFilterMode() == true; // The order in which we set focusable in touch mode/focusable may matter // for the client, see View.setFocusableInTouchMode() comments for more // details super.setFocusableInTouchMode(focusable == true && desiredFocusableInTouchModeState == true); super.setFocusable(focusable == true && desiredFocusableState == true); if (emptyView != null) { updateEmptyStatus((adapter == null) || adapter.isEmpty() == true); } } /** * Update the status of the list based on the empty parameter. If empty is true and we have an empty view, display it. In all the other cases, make * sure that the listview is VISIBLE and that the empty view is GONE (if it's not null). */ @SuppressLint("WrongCall") private void updateEmptyStatus(boolean empty) { if (isInFilterMode() == true) { empty = false; } if (empty == true) { if (emptyView != null) { emptyView.setVisibility(View.VISIBLE); setVisibility(View.GONE); } else { // If the caller just removed our empty view, make sure the list view is visible setVisibility(View.VISIBLE); } // We are now GONE, so pending layouts will not be dispatched. // Force one here to make sure that the state of the list matches // the state of the adapter. if (dataChanged == true) { this.onLayout(false, getLeft(), getTop(), getRight(), getBottom()); } } else { if (emptyView != null) { emptyView.setVisibility(View.GONE); } setVisibility(View.VISIBLE); } } /** * Gets the data associated with the specified position in the list. * * @param position Which data to get * @return The data associated with the specified position in the list */ public Object getItemAtPosition(int position) { final T adapter = getAdapter(); return (adapter == null || position < 0) ? null : adapter.getItem(position); } protected void selectionChanged() { if (onItemSelectedListener != null) { if (isInLayout == true || blockLayoutRequests == true) { // If we are in a layout traversal, defer notification // by posting. This ensures that the view tree is // in a consistent state and is able to accomodate // new layout or invalidate requests. if (selectionNotifier == null) { selectionNotifier = new SelectionNotifier(); } selectionNotifier.post(selectionNotifier); } else { fireOnSelected(); } } // we fire selection events here not in View if (selectedPosition != ListView.INVALID_POSITION && isShown() == true && isInTouchMode() == false) { sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_SELECTED); } } private void fireOnSelected() { if (onItemSelectedListener == null) { return; } final int selection = this.getSelectedItemPosition(); if (selection >= 0) { final View v = getSelectedView(); onItemSelectedListener.onItemSelected(this, v, selection, getAdapter().getItemId(selection)); } else { onItemSelectedListener.onNothingSelected(this); } } public long getItemIdAtPosition(int position) { final T adapter = getAdapter(); return (adapter == null || position < 0) ? INVALID_ROW_ID : adapter.getItemId(position); } protected void handleDataChanged() { final int count = itemCount; boolean found = false; if (count > 0) { int newPos; // Find the row we are supposed to sync to if (needSync == true) { // Update this first, since setNextSelectedPositionInt inspects it needSync = false; // See if we can find a position in the new data with the same id as the old selection newPos = findSyncPosition(); if (newPos >= 0) { // Verify that new selection is selectable final int selectablePos = lookForSelectablePosition(newPos); if (selectablePos == newPos) { // Same row id is selected setNextSelectedPositionInt(newPos); found = true; } } } if (found == false) { // Try to use the same position if we can't find matching data newPos = getSelectedItemPosition(); // Pin position to the available range if (newPos >= count) { newPos = count - 1; } if (newPos < 0) { newPos = 0; } // Make sure we select something selectable -- first look down int selectablePos = lookForSelectablePosition(newPos); if (selectablePos < 0) { // Looking down didn't work -- try looking up selectablePos = lookForSelectablePosition(newPos); } if (selectablePos >= 0) { setNextSelectedPositionInt(selectablePos); checkSelectionChanged(); found = true; } } } if (found == false) { // Nothing is selected selectedPosition = INVALID_POSITION; selectedRowId = INVALID_ROW_ID; nextSelectedPosition = INVALID_POSITION; nextSelectedRowId = INVALID_ROW_ID; needSync = false; checkSelectionChanged(); } } protected void checkSelectionChanged() { if ((selectedPosition != oldSelectedPosition) || (selectedRowId != oldSelectedRowId)) { selectionChanged(); oldSelectedPosition = selectedPosition; oldSelectedRowId = selectedRowId; } } /** * Searches the adapter for a position matching syncRowId. The search starts at syncPosition and then alternates between moving up and moving down * until 1) we find the right position, or 2) we run out of time, or 3) we have looked at every position * * @return Position of the row that matches syncRowId, or {@link #INVALID_POSITION} if it can't be found */ private int findSyncPosition() { final int count = itemCount; if (count == 0) { return INVALID_POSITION; } final long idToMatch = syncRowId; // If there isn't a selection don't hunt for it if (idToMatch == INVALID_ROW_ID) { return INVALID_POSITION; } // Pin seed to reasonable values int seed = syncPosition; seed = Math.max(0, seed); seed = Math.min(count - 1, seed); long rowId; final long endTime = SystemClock.uptimeMillis() + CarouselBaseAdapter.SYNC_MAX_DURATION_MILLIS; // first position scanned so far int first = seed; // last position scanned so far int last = seed; // True if we should move down on the next iteration boolean next = false; // True when we have looked at the first item in the data boolean hitFirst; // True when we have looked at the last item in the data boolean hitLast; // Get the item ID locally (instead of getItemIdAtPosition), so // we need the adapter final T adapter = getAdapter(); if (adapter == null) { return INVALID_POSITION; } while (SystemClock.uptimeMillis() <= endTime) { rowId = adapter.getItemId(seed); if (rowId == idToMatch) { // Found it! return seed; } hitLast = last == count - 1; hitFirst = first == 0; if (hitLast == true && hitFirst == true) { // Looked at everything break; } if (hitFirst == true || (next == true && hitLast == false)) { // Either we hit the top, or we are trying to move down last++; seed = last; // Try going up next time next = false; } else if (hitLast == true || (next == false && hitFirst == false)) { // Either we hit the bottom, or we are trying to move up first--; seed = first; // Try going down next time next = true; } } return INVALID_POSITION; } /** * Find a position that can be selected (i.e., is not a separator). * * @param position The starting position to look at. * @return The next selectable position starting at position and then searching either up or down. Returns {@link #INVALID_POSITION} if nothing can * be found. */ private int lookForSelectablePosition(int position) { return position; } /** * Utility to keep selectedPosition and selectedRowId in sync * * @param position Our current position */ protected void setSelectedPositionInt(int position) { selectedPosition = position; selectedRowId = getItemIdAtPosition(position); } /** * Utility to keep nextSelectedPosition and nextSelectedRowId in sync * * @param position Intended value for selectedPosition the next time we go through layout */ protected void setNextSelectedPositionInt(int position) { nextSelectedPosition = position; nextSelectedRowId = getItemIdAtPosition(position); // If we are trying to sync to the selection, update that too if (needSync == true && syncMode == CarouselBaseAdapter.SYNC_SELECTED_POSITION && position >= 0) { syncPosition = position; syncRowId = nextSelectedRowId; } } /** * Remember enough information to restore the screen state when the data has changed. */ private void rememberSyncState() { if (getChildCount() > 0) { needSync = true; if (selectedPosition >= 0) { // Sync the selection state syncRowId = nextSelectedRowId; syncPosition = nextSelectedPosition; syncMode = CarouselBaseAdapter.SYNC_SELECTED_POSITION; } else { // Sync the based on the offset of the first view final T adapter = getAdapter(); if (firstPosition >= 0 && firstPosition < adapter.getCount()) { syncRowId = adapter.getItemId(firstPosition); } else { syncRowId = NO_ID; } syncPosition = firstPosition; syncMode = CarouselBaseAdapter.SYNC_FIRST_POSITION; } } } @Override public void setFocusable(boolean focusable) { final T adapter = getAdapter(); final boolean empty = adapter == null || adapter.getCount() == 0; desiredFocusableState = focusable; if (focusable == false) { desiredFocusableInTouchModeState = false; } super.setFocusable(focusable == true && (empty == false || isInFilterMode() == true)); } @Override public void setFocusableInTouchMode(boolean focusable) { final T adapter = getAdapter(); final boolean empty = adapter == null || adapter.getCount() == 0; desiredFocusableInTouchModeState = focusable; if (focusable == true) { desiredFocusableState = true; } super.setFocusableInTouchMode(focusable == true && (empty == false || isInFilterMode() == true)); } @Override public void setOnClickListener(OnClickListener l) { throw new RuntimeException("Don't call setOnClickListener for an CarouselAdapter. " + "You probably want setOnItemClickListener instead"); } /** * Override to prevent freezing of any views created by the adapter. */ @Override protected void dispatchSaveInstanceState(SparseArray<Parcelable> container) { dispatchFreezeSelfOnly(container); } /** * Override to prevent thawing of any views created by the adapter. */ @Override protected void dispatchRestoreInstanceState(SparseArray<Parcelable> container) { dispatchThawSelfOnly(container); } @Override public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) { boolean populated = false; // This is an exceptional case which occurs when a window gets the // focus and sends a focus event via its focused child to announce // current focus/selection. CarouselAdapter fires selection but not focus // events so we change the event type here. if (event.getEventType() == AccessibilityEvent.TYPE_VIEW_FOCUSED) { event.setEventType(AccessibilityEvent.TYPE_VIEW_SELECTED); } // we send selection events only from CarouselAdapter to avoid // generation of such event for each child final View selectedView = getSelectedView(); if (selectedView != null) { populated = selectedView.dispatchPopulateAccessibilityEvent(event); } if (populated == false) { if (selectedView != null) { event.setEnabled(selectedView.isEnabled()); } event.setItemCount(getCount()); event.setCurrentItemIndex(getSelectedItemPosition()); } return populated; } @Override protected boolean canAnimate() { return super.canAnimate() == true && itemCount > 0; } /** * This method is not supported and throws an UnsupportedOperationException when called. * * @param child Ignored. * @throws UnsupportedOperationException Every time this method is invoked. */ @Override public void addView(View child) { throw new UnsupportedOperationException("addView(View) is not supported in CarouselAdapter"); } /** * This method is not supported and throws an UnsupportedOperationException when called. * * @param child Ignored. * @param index Ignored. * @throws UnsupportedOperationException Every time this method is invoked. */ @Override public void addView(View child, int index) { throw new UnsupportedOperationException("addView(View, int) is not supported in CarouselAdapter"); } /** * This method is not supported and throws an UnsupportedOperationException when called. * * @param child Ignored. * @param params Ignored. * @throws UnsupportedOperationException Every time this method is invoked. */ @Override public void addView(View child, LayoutParams params) { throw new UnsupportedOperationException("addView(View, LayoutParams) " + "is not supported in CarouselAdapter"); } /** * This method is not supported and throws an UnsupportedOperationException when called. * * @param child Ignored. * @param index Ignored. * @param params Ignored. * @throws UnsupportedOperationException Every time this method is invoked. */ @Override public void addView(View child, int index, LayoutParams params) { throw new UnsupportedOperationException("addView(View, int, LayoutParams) " + "is not supported in CarouselAdapter"); } /** * This method is not supported and throws an UnsupportedOperationException when called. * * @param child Ignored. * @throws UnsupportedOperationException Every time this method is invoked. */ @Override public void removeView(View child) { throw new UnsupportedOperationException("removeView(View) is not supported in CarouselAdapter"); } /** * This method is not supported and throws an UnsupportedOperationException when called. * * @param index Ignored. * @throws UnsupportedOperationException Every time this method is invoked. */ @Override public void removeViewAt(int index) { throw new UnsupportedOperationException("removeViewAt(int) is not supported in CarouselAdapter"); } /** * This method is not supported and throws an UnsupportedOperationException when called. * * @throws UnsupportedOperationException Every time this method is invoked. */ @Override public void removeAllViews() { throw new UnsupportedOperationException("removeAllViews() is not supported in CarouselAdapter"); } @Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { } /** * Returns the adapter currently associated with this widget. * * @return The adapter used to provide this view's content. */ public abstract T getAdapter(); /** * Sets the adapter that provides the data and the views to represent the data in this widget. * * @param adapter The adapter to use to create this view's content. */ public abstract void setAdapter(T adapter); /** * @return The view corresponding to the currently selected item, or null if nothing is selected */ public abstract View getSelectedView(); /** * Sets the currently selected item. To support accessibility subclasses that override this method must invoke the overriden super method first. * * @param position Index (starting at 0) of the data item to be selected. */ public abstract void setSelection(int position); }