Java tutorial
/* * Copyright (C) 2006 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 android.view; import android.annotation.StringRes; import android.app.Activity; import android.content.ComponentName; import android.content.Intent; /** * Interface for managing the items in a menu. * <p> * By default, every Activity supports an options menu of actions or options. * You can add items to this menu and handle clicks on your additions. The * easiest way of adding menu items is inflating an XML file into the * {@link Menu} via {@link MenuInflater}. The easiest way of attaching code to * clicks is via {@link Activity#onOptionsItemSelected(MenuItem)} and * {@link Activity#onContextItemSelected(MenuItem)}. * <p> * Different menu types support different features: * <ol> * <li><b>Context menus</b>: Do not support item shortcuts and item icons. * <li><b>Options menus</b>: The <b>icon menus</b> do not support item check * marks and only show the item's * {@link MenuItem#setTitleCondensed(CharSequence) condensed title}. The * <b>expanded menus</b> (only available if six or more menu items are visible, * reached via the 'More' item in the icon menu) do not show item icons, and * item check marks are discouraged. * <li><b>Sub menus</b>: Do not support item icons, or nested sub menus. * </ol> * * <div class="special reference"> * <h3>Developer Guides</h3> * <p>For more information about creating menus, read the * <a href="{@docRoot}guide/topics/ui/menus.html">Menus</a> developer guide.</p> * </div> */ public interface Menu { /** * This is the part of an order integer that the user can provide. * @hide */ static final int USER_MASK = 0x0000ffff; /** * Bit shift of the user portion of the order integer. * @hide */ static final int USER_SHIFT = 0; /** * This is the part of an order integer that supplies the category of the * item. * @hide */ static final int CATEGORY_MASK = 0xffff0000; /** * Bit shift of the category portion of the order integer. * @hide */ static final int CATEGORY_SHIFT = 16; /** * A mask of all supported modifiers for MenuItem's keyboard shortcuts */ static final int SUPPORTED_MODIFIERS_MASK = KeyEvent.META_META_ON | KeyEvent.META_CTRL_ON | KeyEvent.META_ALT_ON | KeyEvent.META_SHIFT_ON | KeyEvent.META_SYM_ON | KeyEvent.META_FUNCTION_ON; /** * Value to use for group and item identifier integers when you don't care * about them. */ static final int NONE = 0; /** * First value for group and item identifier integers. */ static final int FIRST = 1; // Implementation note: Keep these CATEGORY_* in sync with the category enum // in attrs.xml /** * Category code for the order integer for items/groups that are part of a * container -- or/add this with your base value. */ static final int CATEGORY_CONTAINER = 0x00010000; /** * Category code for the order integer for items/groups that are provided by * the system -- or/add this with your base value. */ static final int CATEGORY_SYSTEM = 0x00020000; /** * Category code for the order integer for items/groups that are * user-supplied secondary (infrequently used) options -- or/add this with * your base value. */ static final int CATEGORY_SECONDARY = 0x00030000; /** * Category code for the order integer for items/groups that are * alternative actions on the data that is currently displayed -- or/add * this with your base value. */ static final int CATEGORY_ALTERNATIVE = 0x00040000; /** * Flag for {@link #addIntentOptions}: if set, do not automatically remove * any existing menu items in the same group. */ static final int FLAG_APPEND_TO_GROUP = 0x0001; /** * Flag for {@link #performShortcut}: if set, do not close the menu after * executing the shortcut. */ static final int FLAG_PERFORM_NO_CLOSE = 0x0001; /** * Flag for {@link #performShortcut(int, KeyEvent, int)}: if set, always * close the menu after executing the shortcut. Closing the menu also resets * the prepared state. */ static final int FLAG_ALWAYS_PERFORM_CLOSE = 0x0002; /** * Add a new item to the menu. This item displays the given title for its * label. * * @param title The text to display for the item. * @return The newly added menu item. */ public MenuItem add(CharSequence title); /** * Add a new item to the menu. This item displays the given title for its * label. * * @param titleRes Resource identifier of title string. * @return The newly added menu item. */ public MenuItem add(@StringRes int titleRes); /** * Add a new item to the menu. This item displays the given title for its * label. * * @param groupId The group identifier that this item should be part of. * This can be used to define groups of items for batch state * changes. Normally use {@link #NONE} if an item should not be in a * group. * @param itemId Unique item ID. Use {@link #NONE} if you do not need a * unique ID. * @param order The order for the item. Use {@link #NONE} if you do not care * about the order. See {@link MenuItem#getOrder()}. * @param title The text to display for the item. * @return The newly added menu item. */ public MenuItem add(int groupId, int itemId, int order, CharSequence title); /** * Variation on {@link #add(int, int, int, CharSequence)} that takes a * string resource identifier instead of the string itself. * * @param groupId The group identifier that this item should be part of. * This can also be used to define groups of items for batch state * changes. Normally use {@link #NONE} if an item should not be in a * group. * @param itemId Unique item ID. Use {@link #NONE} if you do not need a * unique ID. * @param order The order for the item. Use {@link #NONE} if you do not care * about the order. See {@link MenuItem#getOrder()}. * @param titleRes Resource identifier of title string. * @return The newly added menu item. */ public MenuItem add(int groupId, int itemId, int order, @StringRes int titleRes); /** * Add a new sub-menu to the menu. This item displays the given title for * its label. To modify other attributes on the submenu's menu item, use * {@link SubMenu#getItem()}. * * @param title The text to display for the item. * @return The newly added sub-menu */ SubMenu addSubMenu(final CharSequence title); /** * Add a new sub-menu to the menu. This item displays the given title for * its label. To modify other attributes on the submenu's menu item, use * {@link SubMenu#getItem()}. * * @param titleRes Resource identifier of title string. * @return The newly added sub-menu */ SubMenu addSubMenu(@StringRes final int titleRes); /** * Add a new sub-menu to the menu. This item displays the given * <var>title</var> for its label. To modify other attributes on the * submenu's menu item, use {@link SubMenu#getItem()}. *<p> * Note that you can only have one level of sub-menus, i.e. you cannnot add * a subMenu to a subMenu: An {@link UnsupportedOperationException} will be * thrown if you try. * * @param groupId The group identifier that this item should be part of. * This can also be used to define groups of items for batch state * changes. Normally use {@link #NONE} if an item should not be in a * group. * @param itemId Unique item ID. Use {@link #NONE} if you do not need a * unique ID. * @param order The order for the item. Use {@link #NONE} if you do not care * about the order. See {@link MenuItem#getOrder()}. * @param title The text to display for the item. * @return The newly added sub-menu */ SubMenu addSubMenu(final int groupId, final int itemId, int order, final CharSequence title); /** * Variation on {@link #addSubMenu(int, int, int, CharSequence)} that takes * a string resource identifier for the title instead of the string itself. * * @param groupId The group identifier that this item should be part of. * This can also be used to define groups of items for batch state * changes. Normally use {@link #NONE} if an item should not be in a group. * @param itemId Unique item ID. Use {@link #NONE} if you do not need a unique ID. * @param order The order for the item. Use {@link #NONE} if you do not care about the * order. See {@link MenuItem#getOrder()}. * @param titleRes Resource identifier of title string. * @return The newly added sub-menu */ SubMenu addSubMenu(int groupId, int itemId, int order, @StringRes int titleRes); /** * Add a group of menu items corresponding to actions that can be performed * for a particular Intent. The Intent is most often configured with a null * action, the data that the current activity is working with, and includes * either the {@link Intent#CATEGORY_ALTERNATIVE} or * {@link Intent#CATEGORY_SELECTED_ALTERNATIVE} to find activities that have * said they would like to be included as optional action. You can, however, * use any Intent you want. * * <p> * See {@link android.content.pm.PackageManager#queryIntentActivityOptions} * for more * details on the <var>caller</var>, <var>specifics</var>, and * <var>intent</var> arguments. The list returned by that function is used * to populate the resulting menu items. * * <p> * All of the menu items of possible options for the intent will be added * with the given group and id. You can use the group to control ordering of * the items in relation to other items in the menu. Normally this function * will automatically remove any existing items in the menu in the same * group and place a divider above and below the added items; this behavior * can be modified with the <var>flags</var> parameter. For each of the * generated items {@link MenuItem#setIntent} is called to associate the * appropriate Intent with the item; this means the activity will * automatically be started for you without having to do anything else. * * @param groupId The group identifier that the items should be part of. * This can also be used to define groups of items for batch state * changes. Normally use {@link #NONE} if the items should not be in * a group. * @param itemId Unique item ID. Use {@link #NONE} if you do not need a * unique ID. * @param order The order for the items. Use {@link #NONE} if you do not * care about the order. See {@link MenuItem#getOrder()}. * @param caller The current activity component name as defined by * queryIntentActivityOptions(). * @param specifics Specific items to place first as defined by * queryIntentActivityOptions(). * @param intent Intent describing the kinds of items to populate in the * list as defined by queryIntentActivityOptions(). * @param flags Additional options controlling how the items are added. * @param outSpecificItems Optional array in which to place the menu items * that were generated for each of the <var>specifics</var> that were * requested. Entries may be null if no activity was found for that * specific action. * @return The number of menu items that were added. * * @see #FLAG_APPEND_TO_GROUP * @see MenuItem#setIntent * @see android.content.pm.PackageManager#queryIntentActivityOptions */ public int addIntentOptions(int groupId, int itemId, int order, ComponentName caller, Intent[] specifics, Intent intent, int flags, MenuItem[] outSpecificItems); /** * Remove the item with the given identifier. * * @param id The item to be removed. If there is no item with this * identifier, nothing happens. */ public void removeItem(int id); /** * Remove all items in the given group. * * @param groupId The group to be removed. If there are no items in this * group, nothing happens. */ public void removeGroup(int groupId); /** * Remove all existing items from the menu, leaving it empty as if it had * just been created. */ public void clear(); /** * Control whether a particular group of items can show a check mark. This * is similar to calling {@link MenuItem#setCheckable} on all of the menu items * with the given group identifier, but in addition you can control whether * this group contains a mutually-exclusive set items. This should be called * after the items of the group have been added to the menu. * * @param group The group of items to operate on. * @param checkable Set to true to allow a check mark, false to * disallow. The default is false. * @param exclusive If set to true, only one item in this group can be * checked at a time; checking an item will automatically * uncheck all others in the group. If set to false, each * item can be checked independently of the others. * * @see MenuItem#setCheckable * @see MenuItem#setChecked */ public void setGroupCheckable(int group, boolean checkable, boolean exclusive); /** * Show or hide all menu items that are in the given group. * * @param group The group of items to operate on. * @param visible If true the items are visible, else they are hidden. * * @see MenuItem#setVisible */ public void setGroupVisible(int group, boolean visible); /** * Enable or disable all menu items that are in the given group. * * @param group The group of items to operate on. * @param enabled If true the items will be enabled, else they will be disabled. * * @see MenuItem#setEnabled */ public void setGroupEnabled(int group, boolean enabled); /** * Return whether the menu currently has item items that are visible. * * @return True if there is one or more item visible, * else false. */ public boolean hasVisibleItems(); /** * Return the menu item with a particular identifier. * * @param id The identifier to find. * * @return The menu item object, or null if there is no item with * this identifier. */ public MenuItem findItem(int id); /** * Get the number of items in the menu. Note that this will change any * times items are added or removed from the menu. * * @return The item count. */ public int size(); /** * Gets the menu item at the given index. * * @param index The index of the menu item to return. * @return The menu item. * @exception IndexOutOfBoundsException * when {@code index < 0 || >= size()} */ public MenuItem getItem(int index); /** * Closes the menu, if open. */ public void close(); /** * Execute the menu item action associated with the given shortcut * character. * * @param keyCode The keycode of the shortcut key. * @param event Key event message. * @param flags Additional option flags or 0. * * @return If the given shortcut exists and is shown, returns * true; else returns false. * * @see #FLAG_PERFORM_NO_CLOSE */ public boolean performShortcut(int keyCode, KeyEvent event, int flags); /** * Is a keypress one of the defined shortcut keys for this window. * @param keyCode the key code from {@link KeyEvent} to check. * @param event the {@link KeyEvent} to use to help check. */ boolean isShortcutKey(int keyCode, KeyEvent event); /** * Execute the menu item action associated with the given menu identifier. * * @param id Identifier associated with the menu item. * @param flags Additional option flags or 0. * * @return If the given identifier exists and is shown, returns * true; else returns false. * * @see #FLAG_PERFORM_NO_CLOSE */ public boolean performIdentifierAction(int id, int flags); /** * Control whether the menu should be running in qwerty mode (alphabetic * shortcuts) or 12-key mode (numeric shortcuts). * * @param isQwerty If true the menu will use alphabetic shortcuts; else it * will use numeric shortcuts. */ public void setQwertyMode(boolean isQwerty); /** * Enable or disable the group dividers. */ default void setGroupDividerEnabled(boolean groupDividerEnabled) { } }