/*
* 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 com.android.internal.view.menu.MenuItemImpl;
import java.io.IOException;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import android.app.Activity;
import android.content.Context;
import android.content.res.TypedArray;
import android.content.res.XmlResourceParser;
import android.util.AttributeSet;
import android.util.Xml;
/**
* This class is used to instantiate menu XML files into Menu objects.
* <p>
* For performance reasons, menu inflation relies heavily on pre-processing of
* XML files that is done at build time. Therefore, it is not currently possible
* to use MenuInflater with an XmlPullParser over a plain XML file at runtime;
* it only works with an XmlPullParser returned from a compiled resource (R.
* <em>something</em> file.)
*/
public class MenuInflater {
/** Menu tag name in XML. */
private static final String XML_MENU = "menu";
/** Group tag name in XML. */
private static final String XML_GROUP = "group";
/** Item tag name in XML. */
private static final String XML_ITEM = "item";
private static final int NO_ID = 0;
private Context mContext;
/**
* Constructs a menu inflater.
*
* @see Activity#getMenuInflater()
*/
public MenuInflater(Context context) {
mContext = context;
}
/**
* Inflate a menu hierarchy from the specified XML resource. Throws
* {@link InflateException} if there is an error.
*
* @param menuRes Resource ID for an XML layout resource to load (e.g.,
* <code>R.menu.main_activity</code>)
* @param menu The Menu to inflate into. The items and submenus will be
* added to this Menu.
*/
public void inflate(int menuRes, Menu menu) {
XmlResourceParser parser = null;
try {
parser = mContext.getResources().getLayout(menuRes);
AttributeSet attrs = Xml.asAttributeSet(parser);
parseMenu(parser, attrs, menu);
} catch (XmlPullParserException e) {
throw new InflateException("Error inflating menu XML", e);
} catch (IOException e) {
throw new InflateException("Error inflating menu XML", e);
} finally {
if (parser != null) parser.close();
}
}
/**
* Called internally to fill the given menu. If a sub menu is seen, it will
* call this recursively.
*/
private void parseMenu(XmlPullParser parser, AttributeSet attrs, Menu menu)
throws XmlPullParserException, IOException {
MenuState menuState = new MenuState(menu);
int eventType = parser.getEventType();
String tagName;
boolean lookingForEndOfUnknownTag = false;
String unknownTagName = null;
// This loop will skip to the menu start tag
do {
if (eventType == XmlPullParser.START_TAG) {
tagName = parser.getName();
if (tagName.equals(XML_MENU)) {
// Go to next tag
eventType = parser.next();
break;
}
throw new RuntimeException("Expecting menu, got " + tagName);
}
eventType = parser.next();
} while (eventType != XmlPullParser.END_DOCUMENT);
boolean reachedEndOfMenu = false;
while (!reachedEndOfMenu) {
switch (eventType) {
case XmlPullParser.START_TAG:
if (lookingForEndOfUnknownTag) {
break;
}
tagName = parser.getName();
if (tagName.equals(XML_GROUP)) {
menuState.readGroup(attrs);
} else if (tagName.equals(XML_ITEM)) {
menuState.readItem(attrs);
} else if (tagName.equals(XML_MENU)) {
// A menu start tag denotes a submenu for an item
SubMenu subMenu = menuState.addSubMenuItem();
// Parse the submenu into returned SubMenu
parseMenu(parser, attrs, subMenu);
} else {
lookingForEndOfUnknownTag = true;
unknownTagName = tagName;
}
break;
case XmlPullParser.END_TAG:
tagName = parser.getName();
if (lookingForEndOfUnknownTag && tagName.equals(unknownTagName)) {
lookingForEndOfUnknownTag = false;
unknownTagName = null;
} else if (tagName.equals(XML_GROUP)) {
menuState.resetGroup();
} else if (tagName.equals(XML_ITEM)) {
// Add the item if it hasn't been added (if the item was
// a submenu, it would have been added already)
if (!menuState.hasAddedItem()) {
menuState.addItem();
}
} else if (tagName.equals(XML_MENU)) {
reachedEndOfMenu = true;
}
break;
case XmlPullParser.END_DOCUMENT:
throw new RuntimeException("Unexpected end of document");
}
eventType = parser.next();
}
}
/**
* State for the current menu.
* <p>
* Groups can not be nested unless there is another menu (which will have
* its state class).
*/
private class MenuState {
private Menu menu;
/*
* Group state is set on items as they are added, allowing an item to
* override its group state. (As opposed to set on items at the group end tag.)
*/
private int groupId;
private int groupCategory;
private int groupOrder;
private int groupCheckable;
private boolean groupVisible;
private boolean groupEnabled;
private boolean itemAdded;
private int itemId;
private int itemCategoryOrder;
private String itemTitle;
private String itemTitleCondensed;
private int itemIconResId;
private char itemAlphabeticShortcut;
private char itemNumericShortcut;
/**
* Sync to attrs.xml enum:
* - 0: none
* - 1: all
* - 2: exclusive
*/
private int itemCheckable;
private boolean itemChecked;
private boolean itemVisible;
private boolean itemEnabled;
private static final int defaultGroupId = NO_ID;
private static final int defaultItemId = NO_ID;
private static final int defaultItemCategory = 0;
private static final int defaultItemOrder = 0;
private static final int defaultItemCheckable = 0;
private static final boolean defaultItemChecked = false;
private static final boolean defaultItemVisible = true;
private static final boolean defaultItemEnabled = true;
public MenuState(final Menu menu) {
this.menu = menu;
resetGroup();
}
public void resetGroup() {
groupId = defaultGroupId;
groupCategory = defaultItemCategory;
groupOrder = defaultItemOrder;
groupCheckable = defaultItemCheckable;
groupVisible = defaultItemVisible;
groupEnabled = defaultItemEnabled;
}
/**
* Called when the parser is pointing to a group tag.
*/
public void readGroup(AttributeSet attrs) {
TypedArray a = mContext.obtainStyledAttributes(attrs,
com.android.internal.R.styleable.MenuGroup);
groupId = a.getResourceId(com.android.internal.R.styleable.MenuGroup_id, defaultGroupId);
groupCategory = a.getInt(com.android.internal.R.styleable.MenuGroup_menuCategory, defaultItemCategory);
groupOrder = a.getInt(com.android.internal.R.styleable.MenuGroup_orderInCategory, defaultItemOrder);
groupCheckable = a.getInt(com.android.internal.R.styleable.MenuGroup_checkableBehavior, defaultItemCheckable);
groupVisible = a.getBoolean(com.android.internal.R.styleable.MenuGroup_visible, defaultItemVisible);
groupEnabled = a.getBoolean(com.android.internal.R.styleable.MenuGroup_enabled, defaultItemEnabled);
a.recycle();
}
/**
* Called when the parser is pointing to an item tag.
*/
public void readItem(AttributeSet attrs) {
TypedArray a = mContext.obtainStyledAttributes(attrs,
com.android.internal.R.styleable.MenuItem);
// Inherit attributes from the group as default value
itemId = a.getResourceId(com.android.internal.R.styleable.MenuItem_id, defaultItemId);
final int category = a.getInt(com.android.internal.R.styleable.MenuItem_menuCategory, groupCategory);
final int order = a.getInt(com.android.internal.R.styleable.MenuItem_orderInCategory, groupOrder);
itemCategoryOrder = (category & Menu.CATEGORY_MASK) | (order & Menu.USER_MASK);
itemTitle = a.getString(com.android.internal.R.styleable.MenuItem_title);
itemTitleCondensed = a.getString(com.android.internal.R.styleable.MenuItem_titleCondensed);
itemIconResId = a.getResourceId(com.android.internal.R.styleable.MenuItem_icon, 0);
itemAlphabeticShortcut =
getShortcut(a.getString(com.android.internal.R.styleable.MenuItem_alphabeticShortcut));
itemNumericShortcut =
getShortcut(a.getString(com.android.internal.R.styleable.MenuItem_numericShortcut));
if (a.hasValue(com.android.internal.R.styleable.MenuItem_checkable)) {
// Item has attribute checkable, use it
itemCheckable = a.getBoolean(com.android.internal.R.styleable.MenuItem_checkable, false) ? 1 : 0;
} else {
// Item does not have attribute, use the group's (group can have one more state
// for checkable that represents the exclusive checkable)
itemCheckable = groupCheckable;
}
itemChecked = a.getBoolean(com.android.internal.R.styleable.MenuItem_checked, defaultItemChecked);
itemVisible = a.getBoolean(com.android.internal.R.styleable.MenuItem_visible, groupVisible);
itemEnabled = a.getBoolean(com.android.internal.R.styleable.MenuItem_enabled, groupEnabled);
a.recycle();
itemAdded = false;
}
private char getShortcut(String shortcutString) {
if (shortcutString == null) {
return 0;
} else {
return shortcutString.charAt(0);
}
}
private void setItem(MenuItem item) {
item.setChecked(itemChecked)
.setVisible(itemVisible)
.setEnabled(itemEnabled)
.setCheckable(itemCheckable >= 1)
.setTitleCondensed(itemTitleCondensed)
.setIcon(itemIconResId)
.setAlphabeticShortcut(itemAlphabeticShortcut)
.setNumericShortcut(itemNumericShortcut);
if (itemCheckable >= 2) {
((MenuItemImpl) item).setExclusiveCheckable(true);
}
}
public void addItem() {
itemAdded = true;
setItem(menu.add(groupId, itemId, itemCategoryOrder, itemTitle));
}
public SubMenu addSubMenuItem() {
itemAdded = true;
SubMenu subMenu = menu.addSubMenu(groupId, itemId, itemCategoryOrder, itemTitle);
setItem(subMenu.getItem());
return subMenu;
}
public boolean hasAddedItem() {
return itemAdded;
}
}
}
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