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MenuInflater.javaAPI DocAndroid 1.5 API12931Wed May 06 22:41:56 BST 2009android.view

MenuInflater

public class MenuInflater extends Object
This class is used to instantiate menu XML files into Menu objects.

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. something file.)

Fields Summary
private static final String
XML_MENU
Menu tag name in XML.
private static final String
XML_GROUP
Group tag name in XML.
private static final String
XML_ITEM
Item tag name in XML.
private static final int
NO_ID
private android.content.Context
mContext
Constructors Summary
public MenuInflater(android.content.Context context)
Constructs a menu inflater.

see
Activity#getMenuInflater()

    
                
       
        mContext = context;
Methods Summary
public voidinflate(int menuRes, Menu menu)
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., R.menu.main_activity)
param
menu The Menu to inflate into. The items and submenus will be added to this 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();
        }
private voidparseMenu(org.xmlpull.v1.XmlPullParser parser, android.util.AttributeSet attrs, Menu menu)
Called internally to fill the given menu. If a sub menu is seen, it will call this recursively.

        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();
        }