content: /*
   * Copyright (C) 2011 The Android Open Source Project
   *
   * Licensed under the Apache License, Version 2.0 (the "License");
   * you may not use this file except in compliance with the License.
   * You may obtain a copy of the License at
   *
   *      http://www.apache.org/licenses/LICENSE-2.0
   *
   * Unless required by applicable law or agreed to in writing, software
   * distributed under the License is distributed on an "AS IS" BASIS,
   * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
   * See the License for the specific language governing permissions and
   * limitations under the License.
   */
  
  package com.actionbarsherlock.internal.view.menu;
  
  import android.content.Context;
  import android.os.Parcelable;
  import android.view.ViewGroup;
  
  /**
   * A MenuPresenter is responsible for building views for a Menu object.
   * It takes over some responsibility from the old style monolithic MenuBuilder class.
   */
  public interface MenuPresenter {
      /**
       * Called by menu implementation to notify another component of open/close events.
       */
      public interface Callback {
          /**
           * Called when a menu is closing.
           * @param menu
           * @param allMenusAreClosing
           */
          public void onCloseMenu(MenuBuilder menu, boolean allMenusAreClosing);
  
          /**
           * Called when a submenu opens. Useful for notifying the application
           * of menu state so that it does not attempt to hide the action bar
           * while a submenu is open or similar.
           *
           * @param subMenu Submenu currently being opened
           * @return true if the Callback will handle presenting the submenu, false if
           *         the presenter should attempt to do so.
           */
          public boolean onOpenSubMenu(MenuBuilder subMenu);
      }
  
      /**
       * Initialize this presenter for the given context and menu.
       * This method is called by MenuBuilder when a presenter is
       * added. See {@link MenuBuilder#addMenuPresenter(MenuPresenter)}
       *
       * @param context Context for this presenter; used for view creation and resource management
       * @param menu Menu to host
       */
      public void initForMenu(Context context, MenuBuilder menu);
  
      /**
       * Retrieve a MenuView to display the menu specified in
       * {@link #initForMenu(Context, Menu)}.
       *
       * @param root Intended parent of the MenuView.
       * @return A freshly created MenuView.
       */
      public MenuView getMenuView(ViewGroup root);
  
      /**
       * Update the menu UI in response to a change. Called by
       * MenuBuilder during the normal course of operation.
       *
       * @param cleared true if the menu was entirely cleared
       */
      public void updateMenuView(boolean cleared);
  
      /**
       * Set a callback object that will be notified of menu events
       * related to this specific presentation.
       * @param cb Callback that will be notified of future events
       */
      public void setCallback(Callback cb);
  
      /**
       * Called by Menu implementations to indicate that a submenu item
       * has been selected. An active Callback should be notified, and
       * if applicable the presenter should present the submenu.
       *
       * @param subMenu SubMenu being opened
       * @return true if the the event was handled, false otherwise.
       */
      public boolean onSubMenuSelected(SubMenuBuilder subMenu);
  
      /**
       * Called by Menu implementations to indicate that a menu or submenu is
       * closing. Presenter implementations should close the representation
       * of the menu indicated as necessary and notify a registered callback.
       *
       * @param menu Menu or submenu that is closing.
       * @param allMenusAreClosing True if all associated menus are closing.
       */
      public void onCloseMenu(MenuBuilder menu, boolean allMenusAreClosing);
  
      /**
       * Called by Menu implementations to flag items that will be shown as actions.
       * @return true if this presenter changed the action status of any items.
       */
      public boolean flagActionItems();
  
      /**
       * Called when a menu item with a collapsable action view should expand its action view.
       *
       * @param menu Menu containing the item to be expanded
       * @param item Item to be expanded
       * @return true if this presenter expanded the action view, false otherwise.
       */
      public boolean expandItemActionView(MenuBuilder menu, MenuItemImpl item);
  
      /**
       * Called when a menu item with a collapsable action view should collapse its action view.
       *
       * @param menu Menu containing the item to be collapsed
       * @param item Item to be collapsed
       * @return true if this presenter collapsed the action view, false otherwise.
       */
      public boolean collapseItemActionView(MenuBuilder menu, MenuItemImpl item);
  
      /**
       * Returns an ID for determining how to save/restore instance state.
       * @return a valid ID value.
       */
      public int getId();
  
      /**
       * Returns a Parcelable describing the current state of the presenter.
       * It will be passed to the {@link #onRestoreInstanceState(Parcelable)}
       * method of the presenter sharing the same ID later.
       * @return The saved instance state
       */
      public Parcelable onSaveInstanceState();
  
      /**
       * Supplies the previously saved instance state to be restored.
       * @param state The previously saved instance state
       */
      public void onRestoreInstanceState(Parcelable state);
  }
  