sdk/sources/android-25/android/support/v7/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 android.support.v7.view.menu;
  18
  19 import android.content.Context;
  20 import android.os.Parcelable;
  21 import android.support.annotation.RestrictTo;
  22 import android.view.ViewGroup;
  23
  24 import static android.support.annotation.RestrictTo.Scope.GROUP_ID;
  25
  26 /**
  27  * A MenuPresenter is responsible for building views for a Menu object. It takes over some
  28  * responsibility from the old style monolithic MenuBuilder class.
  29  *
  30  * @hide
  31  */
  32 @RestrictTo(GROUP_ID)
  33 public interface MenuPresenter {
  34
  35     /**
  36      * Called by menu implementation to notify another component of open/close events.
  37      */
  38     interface Callback {
  39         /**
  40          * Called when a menu is closing.
  41          * @param menu
  42          * @param allMenusAreClosing
  43          */
  44         void onCloseMenu(MenuBuilder menu, boolean allMenusAreClosing);
  45
  46         /**
  47          * Called when a submenu opens. Useful for notifying the application
  48          * of menu state so that it does not attempt to hide the action bar
  49          * while a submenu is open or similar.
  50          *
  51          * @param subMenu Submenu currently being opened
  52          * @return true if the Callback will handle presenting the submenu, false if
  53          *         the presenter should attempt to do so.
  54          */
  55         boolean onOpenSubMenu(MenuBuilder subMenu);
  56     }
  57
  58     /**
  59      * Initialize this presenter for the given context and menu.
  60      * This method is called by MenuBuilder when a presenter is
  61      * added. See {@link MenuBuilder#addMenuPresenter(MenuPresenter)}
  62      *
  63      * @param context Context for this presenter; used for view creation and resource management
  64      * @param menu Menu to host
  65      */
  66     void initForMenu(Context context, MenuBuilder menu);
  67
  68     /**
  69      * Retrieve a MenuView to display the menu specified in
  70      * {@link #initForMenu(Context, MenuBuilder)}.
  71      *
  72      * @param root Intended parent of the MenuView.
  73      * @return A freshly created MenuView.
  74      */
  75     MenuView getMenuView(ViewGroup root);
  76
  77     /**
  78      * Update the menu UI in response to a change. Called by
  79      * MenuBuilder during the normal course of operation.
  80      *
  81      * @param cleared true if the menu was entirely cleared
  82      */
  83     void updateMenuView(boolean cleared);
  84
  85     /**
  86      * Set a callback object that will be notified of menu events
  87      * related to this specific presentation.
  88      * @param cb Callback that will be notified of future events
  89      */
  90     void setCallback(Callback cb);
  91
  92     /**
  93      * Called by Menu implementations to indicate that a submenu item
  94      * has been selected. An active Callback should be notified, and
  95      * if applicable the presenter should present the submenu.
  96      *
  97      * @param subMenu SubMenu being opened
  98      * @return true if the the event was handled, false otherwise.
  99      */
 100     boolean onSubMenuSelected(SubMenuBuilder subMenu);
 101
 102     /**
 103      * Called by Menu implementations to indicate that a menu or submenu is
 104      * closing. Presenter implementations should close the representation
 105      * of the menu indicated as necessary and notify a registered callback.
 106      *
 107      * @param menu Menu or submenu that is closing.
 108      * @param allMenusAreClosing True if all associated menus are closing.
 109      */
 110     void onCloseMenu(MenuBuilder menu, boolean allMenusAreClosing);
 111
 112     /**
 113      * Called by Menu implementations to flag items that will be shown as actions.
 114      * @return true if this presenter changed the action status of any items.
 115      */
 116     boolean flagActionItems();
 117
 118     /**
 119      * Called when a menu item with a collapsible action view should expand its action view.
 120      *
 121      * @param menu Menu containing the item to be expanded
 122      * @param item Item to be expanded
 123      * @return true if this presenter expanded the action view, false otherwise.
 124      */
 125     boolean expandItemActionView(MenuBuilder menu, MenuItemImpl item);
 126
 127     /**
 128      * Called when a menu item with a collapsible action view should collapse its action view.
 129      *
 130      * @param menu Menu containing the item to be collapsed
 131      * @param item Item to be collapsed
 132      * @return true if this presenter collapsed the action view, false otherwise.
 133      */
 134     boolean collapseItemActionView(MenuBuilder menu, MenuItemImpl item);
 135
 136     /**
 137      * Returns an ID for determining how to save/restore instance state.
 138      * @return a valid ID value.
 139      */
 140     int getId();
 141
 142     /**
 143      * Returns a Parcelable describing the current state of the presenter.
 144      * It will be passed to the {@link #onRestoreInstanceState(Parcelable)}
 145      * method of the presenter sharing the same ID later.
 146      * @return The saved instance state
 147      */
 148     Parcelable onSaveInstanceState();
 149
 150     /**
 151      * Supplies the previously saved instance state to be restored.
 152      * @param state The previously saved instance state
 153      */
 154     void onRestoreInstanceState(Parcelable state);
 155 }