MenuPresenter.java revision 696cba573e651b0e4f18a4718627c8ccecb3bda0 
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
17package com.android.internal.view.menu;
18
19import android.content.Context;
20import android.view.Menu;
21import 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 */
27public 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