actionbarsherlock/src/com/actionbarsherlock/internal/view/menu/MenuPresenter.java

   1 /*
   2  * Copyright (C) 2011 The Android Open Source Project
   3  *
   4  * Licensed under the Apache License, Version 2.0 (the "License");
   5  * you may not use this file except in compliance with the License.
   6  * You may obtain a copy of the License at
   7  *
   8  *      http://www.apache.org/licenses/LICENSE-2.0
   9  *
  10  * Unless required by applicable law or agreed to in writing, software
  11  * distributed under the License is distributed on an "AS IS" BASIS,
  12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
  13  * See the License for the specific language governing permissions and
  14  * limitations under the License.
  15  */
  16
  17 package com.actionbarsherlock.internal.view.menu;
  18
  19 import android.content.Context;
  20 import android.os.Parcelable;
  21 import android.view.ViewGroup;
  22
  23 /**
  24  * A MenuPresenter is responsible for building views for a Menu object.
  25  * It takes over some responsibility from the old style monolithic MenuBuilder class.
  26  */
  27 public interface MenuPresenter {
  28     /**
  29      * Called by menu implementation to notify another component of open/close events.
  30      */
  31     public interface Callback {
  32         /**
  33          * Called when a menu is closing.
  34          * @param menu
  35          * @param allMenusAreClosing
  36          */
  37         public void onCloseMenu(MenuBuilder menu, boolean allMenusAreClosing);
  38
  39         /**
  40          * Called when a submenu opens. Useful for notifying the application
  41          * of menu state so that it does not attempt to hide the action bar
  42          * while a submenu is open or similar.
  43          *
  44          * @param subMenu Submenu currently being opened
  45          * @return true if the Callback will handle presenting the submenu, false if
  46          *         the presenter should attempt to do so.
  47          */
  48         public boolean onOpenSubMenu(MenuBuilder subMenu);
  49     }
  50
  51     /**
  52      * Initialize this presenter for the given context and menu.
  53      * This method is called by MenuBuilder when a presenter is
  54      * added. See {@link MenuBuilder#addMenuPresenter(MenuPresenter)}
  55      *
  56      * @param context Context for this presenter; used for view creation and resource management
  57      * @param menu Menu to host
  58      */
  59     public void initForMenu(Context context, MenuBuilder menu);
  60
  61     /**
  62      * Retrieve a MenuView to display the menu specified in
  63      * {@link #initForMenu(Context, Menu)}.
  64      *
  65      * @param root Intended parent of the MenuView.
  66      * @return A freshly created MenuView.
  67      */
  68     public MenuView getMenuView(ViewGroup root);
  69
  70     /**
  71      * Update the menu UI in response to a change. Called by
  72      * MenuBuilder during the normal course of operation.
  73      *
  74      * @param cleared true if the menu was entirely cleared
  75      */
  76     public void updateMenuView(boolean cleared);
  77
  78     /**
  79      * Set a callback object that will be notified of menu events
  80      * related to this specific presentation.
  81      * @param cb Callback that will be notified of future events
  82      */
  83     public void setCallback(Callback cb);
  84
  85     /**
  86      * Called by Menu implementations to indicate that a submenu item
  87      * has been selected. An active Callback should be notified, and
  88      * if applicable the presenter should present the submenu.
  89      *
  90      * @param subMenu SubMenu being opened
  91      * @return true if the the event was handled, false otherwise.
  92      */
  93     public boolean onSubMenuSelected(SubMenuBuilder subMenu);
  94
  95     /**
  96      * Called by Menu implementations to indicate that a menu or submenu is
  97      * closing. Presenter implementations should close the representation
  98      * of the menu indicated as necessary and notify a registered callback.
  99      *
 100      * @param menu Menu or submenu that is closing.
 101      * @param allMenusAreClosing True if all associated menus are closing.
 102      */
 103     public void onCloseMenu(MenuBuilder menu, boolean allMenusAreClosing);
 104
 105     /**
 106      * Called by Menu implementations to flag items that will be shown as actions.
 107      * @return true if this presenter changed the action status of any items.
 108      */
 109     public boolean flagActionItems();
 110
 111     /**
 112      * Called when a menu item with a collapsable action view should expand its action view.
 113      *
 114      * @param menu Menu containing the item to be expanded
 115      * @param item Item to be expanded
 116      * @return true if this presenter expanded the action view, false otherwise.
 117      */
 118     public boolean expandItemActionView(MenuBuilder menu, MenuItemImpl item);
 119
 120     /**
 121      * Called when a menu item with a collapsable action view should collapse its action view.
 122      *
 123      * @param menu Menu containing the item to be collapsed
 124      * @param item Item to be collapsed
 125      * @return true if this presenter collapsed the action view, false otherwise.
 126      */
 127     public boolean collapseItemActionView(MenuBuilder menu, MenuItemImpl item);
 128
 129     /**
 130      * Returns an ID for determining how to save/restore instance state.
 131      * @return a valid ID value.
 132      */
 133     public int getId();
 134
 135     /**
 136      * Returns a Parcelable describing the current state of the presenter.
 137      * It will be passed to the {@link #onRestoreInstanceState(Parcelable)}
 138      * method of the presenter sharing the same ID later.
 139      * @return The saved instance state
 140      */
 141     public Parcelable onSaveInstanceState();
 142
 143     /**
 144      * Supplies the previously saved instance state to be restored.
 145      * @param state The previously saved instance state
 146      */
 147     public void onRestoreInstanceState(Parcelable state);
 148 }