我想获取活动的布局文件，并使用它们在帮助页面上创建该活动的图像。我想在画布上绘制活动副本。我希望画布上显示的活动图像直接链接到布局文件，这样当我更改活动的布局时，画布上的帮助页面图片将自动更新。
最初，我想使用菜单xml文件来获取ActionBar中使用的图标并在画布上显示它们。我理解如何在画布上显示图标。我想知道如何从布局文件中获取使用的图标（例如android:icon="@drawable/ic_action_save"）。
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android" >
<item android:id="@+id/activity_detail_save"
android:icon="@drawable/ic_action_save"
android:title="@string/save"
android:showAsAction="ifRoom" />
<item android:id="@+id/activity_detail_delete"
android:icon="@drawable/ic_action_delete"
android:title="@string/delete"
android:showAsAction="ifRoom" />
<item android:id="@+id/activity_detail_help"
android:icon="@drawable/ic_action_help"
android:title="@string/help"
android:showAsAction="ifRoom" />
</menu>
我已经看过XMLPullParser作为选项。我想知道是否有更好的方法来做到这一点。是否有一个特定的解析器，适用于Android布局文件？看起来XMLPullParser不会处理和分离字符串。
答案 0 :(得分：2)
我已经破解了MenuInflater XMLPullParser以执行我想要的操作。这是CustomMenuInflater的代码。我留下了注释掉的代码，因为我认为这对于想要访问MenuInflater的不同功能的人来说非常有用。
/*
* 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 com.example.canvaslayout;
//import com.android.internal.view.menu.MenuItemImpl;
import org.xmlpull.v1.XmlPullParser;
import org.xmlpull.v1.XmlPullParserException;
import android.app.Activity;
import android.content.Context;
import android.content.res.Resources;
import android.content.res.TypedArray;
import android.content.res.XmlResourceParser;
import android.util.AttributeSet;
import android.util.Log;
import android.util.Xml;
import android.view.InflateException;
import java.io.IOException;
import java.lang.reflect.Constructor;
import java.util.ArrayList;
/**
* 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 CustomMenuInflater {
private static final String LOG_TAG = "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 static final Class<?>[] ACTION_VIEW_CONSTRUCTOR_SIGNATURE = new Class[] {Context.class};
private static final Class<?>[] ACTION_PROVIDER_CONSTRUCTOR_SIGNATURE = ACTION_VIEW_CONSTRUCTOR_SIGNATURE;
private final Object[] mActionViewConstructorArguments;
private final Object[] mActionProviderConstructorArguments;
private Context mContext;
private Object mRealOwner;
/**
* Constructs a menu inflater.
*
* @see Activity#getMenuInflater()
*/
public CustomMenuInflater(Context context) {
mContext = context;
mRealOwner = context;
mActionViewConstructorArguments = new Object[] {context};
mActionProviderConstructorArguments = mActionViewConstructorArguments;
}
/**
* Constructs a menu inflater.
*
* @see Activity#getMenuInflater()
* @hide
*/
public CustomMenuInflater(Context context, Object realOwner) {
mContext = context;
mRealOwner = realOwner;
mActionViewConstructorArguments = new Object[] {context};
mActionProviderConstructorArguments = mActionViewConstructorArguments;
}
/**
* 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, ArrayList<Integer> intArray) { // TODO inflate to where?
XmlResourceParser parser = null;
try {
parser = mContext.getResources().getLayout(menuRes);
AttributeSet attrs = Xml.asAttributeSet(parser);
Log.d("attrs inflate", Integer.toString(attrs.getAttributeCount()));
parseMenu(parser, attrs, intArray);
} 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, ArrayList<Integer> intArray) // TODO parse tp where
throws XmlPullParserException, IOException {
MenuState menuState = new MenuState();
//intArray = new ArrayList<Integer>();
Log.d("attrs parse", Integer.toString(attrs.getAttributeCount()));
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();
// TODO what if there is a submenu
// 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()) {
/*if (menuState.itemActionProvider != null &&
menuState.itemActionProvider.hasSubMenu()) {
menuState.addSubMenuItem();
} else {
menuState.addItem();
}*/
menuState.addItem(intArray);
}
// TODO addItem() goes here
} else if (tagName.equals(XML_MENU)) {
reachedEndOfMenu = true;
}
break;
case XmlPullParser.END_DOCUMENT:
throw new RuntimeException("Unexpected end of document");
}
eventType = parser.next();
}
}
/*private static class InflatedOnMenuItemClickListener // TODO onClickListener?
implements MenuItem.OnMenuItemClickListener {
private static final Class<?>[] PARAM_TYPES = new Class[] { MenuItem.class };
private Object mRealOwner;
private Method mMethod;
public InflatedOnMenuItemClickListener(Object realOwner, String methodName) {
mRealOwner = realOwner;
Class<?> c = realOwner.getClass();
try {
mMethod = c.getMethod(methodName, PARAM_TYPES);
} catch (Exception e) {
InflateException ex = new InflateException(
"Couldn't resolve menu item onClick handler " + methodName +
" in class " + c.getName());
ex.initCause(e);
throw ex;
}
}
public boolean onMenuItemClick(MenuItem item) {
try {
if (mMethod.getReturnType() == Boolean.TYPE) {
return (Boolean) mMethod.invoke(mRealOwner, item);
} else {
mMethod.invoke(mRealOwner, item);
return true;
}
} catch (Exception e) {
throw new RuntimeException(e);
}
}
}*/
/**
* 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 { // TODO MenuState needs menu?
//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 CharSequence itemTitle;
private CharSequence 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;
/**
* Sync to attrs.xml enum, values in MenuItem:
* - 0: never
* - 1: ifRoom
* - 2: always
* - -1: Safe sentinel for "no value".
*/
private int itemShowAsAction;
private int itemActionViewLayout;
private String itemActionViewClassName;
private String itemActionProviderClassName;
private String itemListenerMethodName;
private android.view.ActionProvider itemActionProvider;
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;
static final int CATEGORY_MASK = 0xffff0000; // TODO may change with new versions of Android - from android.view.Menu
static final int USER_MASK = 0x0000ffff; // TODO may change with new versions of Android - from android.view.Menu
public MenuState() {
//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) {
Resources res = Resources.getSystem();
TypedArray a = mContext.obtainStyledAttributes(attrs,
toIntArray(res.getIdentifier(R.styleable.MenuGroup)));
groupId = a.getResourceId(res.getIdentifier("MenuGroup_id", "styleable", "R"), defaultGroupId);
groupCategory = a.getInt(res.getIdentifier("MenuGroup_menuCategory", "styleable", "R"), defaultItemCategory);
groupOrder = a.getInt(res.getIdentifier("MenuGroup_orderInCategory", "styleable", "R"), defaultItemOrder);
groupCheckable = a.getInt(res.getIdentifier("MenuGroup_checkableBehavior", "styleable", "R"), defaultItemCheckable);
groupVisible = a.getBoolean(res.getIdentifier("MenuGroup_visible", "styleable", "R"), defaultItemVisible);
groupEnabled = a.getBoolean(res.getIdentifier("MenuGroup_enabled", "styleable", "R"), defaultItemEnabled);
a.recycle();
}*/
/**
* Called when the parser is pointing to an item tag.
*/
public void readItem(AttributeSet attrs) {
Resources res = Resources.getSystem();
TypedArray a = mContext.obtainStyledAttributes(attrs, com.example.canvaslayout.R.styleable.MenuItem);
Log.d("a how many items", Integer.toString(a.length()));
Log.d("a 1", "nout:" + attrs.getAttributeValue("http://schemas.android.com/apk/res/res-auto", "MenuItem_id"));
// Inherit attributes from the group as default value
itemId = a.getResourceId(R.styleable.MenuItem_id, defaultItemId);
/*final int category = a.getInt(res.getIdentifier("MenuItem_menuCategory", "styleable", "R"), groupCategory);
final int order = a.getInt(res.getIdentifier("MenuItem_orderInCategory", "styleable", "R"), groupOrder);
itemCategoryOrder = (category & CATEGORY_MASK) | (order & USER_MASK);*/
itemTitle = a.getString(R.styleable.MenuItem_title);
Log.d("itemTitle", a.getString(R.styleable.MenuItem_title));
/*itemTitleCondensed = a.getText(res.getIdentifier("MenuItem_titleCondensed", "styleable", "R"));*/
itemIconResId = a.getResourceId(R.styleable.MenuItem_icon, 0);
Log.d("placed:itemIconResId", Integer.toString(itemIconResId));
/*itemAlphabeticShortcut =
getShortcut(a.getString(res.getIdentifier("MenuItem_alphabeticShortcut", "styleable", "R")));
itemNumericShortcut =
getShortcut(a.getString(res.getIdentifier("MenuItem_numericShortcut", "styleable", "R")));
if (a.hasValue(res.getIdentifier("MenuItem_checkable", "styleable", "R"))) {
// Item has attribute checkable, use it
itemCheckable = a.getBoolean(res.getIdentifier("MenuItem_checkable", "styleable", "R"), 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(res.getIdentifier("MenuItem_checked", "styleable", "R"), defaultItemChecked);
itemVisible = a.getBoolean(res.getIdentifier("MenuItem_visible", "styleable", "R"), groupVisible);
itemEnabled = a.getBoolean(res.getIdentifier("MenuItem_enabled", "styleable", "R"), groupEnabled);
itemShowAsAction = a.getInt(res.getIdentifier("MenuItem_showAsAction", "styleable", "R"), -1);
itemListenerMethodName = a.getString(res.getIdentifier("MenuItem_onClick", "styleable", "R"));
itemActionViewLayout = a.getResourceId(res.getIdentifier("MenuItem_actionLayout", "styleable", "R"), 0);
itemActionViewClassName = a.getString(res.getIdentifier("MenuItem_actionViewClass", "styleable", "R"));
itemActionProviderClassName = a.getString(res.getIdentifier("MenuItem_actionProviderClass", "styleable", "R"));
Log.d("a", Integer.toString(a.getIndexCount()));
final boolean hasActionProvider = itemActionProviderClassName != null;
if (hasActionProvider && itemActionViewLayout == 0 && itemActionViewClassName == null) {
itemActionProvider = newInstance(itemActionProviderClassName,
ACTION_PROVIDER_CONSTRUCTOR_SIGNATURE,
mActionProviderConstructorArguments);
} else {
if (hasActionProvider) {
Log.w(LOG_TAG, "Ignoring attribute 'actionProviderClass'."
+ " Action view already specified.");
}
itemActionProvider = null;
}*/
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 (itemShowAsAction >= 0) {
item.setShowAsAction(itemShowAsAction);
}
if (itemListenerMethodName != null) {
if (mContext.isRestricted()) {
throw new IllegalStateException("The android:onClick attribute cannot "
+ "be used within a restricted context");
}
item.setOnMenuItemClickListener(
new InflatedOnMenuItemClickListener(mRealOwner, itemListenerMethodName));
}
if (item instanceof MenuItemImpl) {
MenuItemImpl impl = (MenuItemImpl) item;
if (itemCheckable >= 2) {
impl.setExclusiveCheckable(true);
}
}
boolean actionViewSpecified = false;
if (itemActionViewClassName != null) {
View actionView = (View) newInstance(itemActionViewClassName,
ACTION_VIEW_CONSTRUCTOR_SIGNATURE, mActionViewConstructorArguments);
item.setActionView(actionView);
actionViewSpecified = true;
}
if (itemActionViewLayout > 0) {
if (!actionViewSpecified) {
item.setActionView(itemActionViewLayout);
actionViewSpecified = true;
} else {
Log.w(LOG_TAG, "Ignoring attribute 'itemActionViewLayout'."
+ " Action view already specified.");
}
}
if (itemActionProvider != null) {
item.setActionProvider(itemActionProvider);
}
}
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 void addItem(ArrayList<Integer> integerArray) {
itemAdded = true;
integerArray.add(itemIconResId);
Log.d("itemIconResId", Integer.toString(itemIconResId));
}
public void addSubMenuItem() {
itemAdded = true;
// TODO add submenu item added method
}
public boolean hasAddedItem() {
return itemAdded;
}
@SuppressWarnings("unchecked")
private <T> T newInstance(String className, Class<?>[] constructorSignature,
Object[] arguments) {
try {
Class<?> clazz = mContext.getClassLoader().loadClass(className);
Constructor<?> constructor = clazz.getConstructor(constructorSignature);
return (T) constructor.newInstance(arguments);
} catch (Exception e) {
Log.w(LOG_TAG, "Cannot instantiate class: " + className, e);
}
return null;
}
}
public int[] toIntArray(int identifier) {
int[] newIntArray = new int[1];
newIntArray[0] = identifier;
return newIntArray;
}
}
以下是与此代码一起使用的xml attrs.xml文件。
<?xml version="1.0" encoding="utf-8"?>
<resources>
<!-- Base attributes that are available to all Item objects. -->
<declare-styleable name="MenuItem">
<!-- The ID of the item. -->
<attr name="id" format="string" />
<!-- The title associated with the item. -->
<attr name="title" format="string" />
<!-- The condensed title associated with the item. This is used in situations where the
normal title may be too long to be displayed. -->
<attr name="titleCondensed" format="string" />
<!-- The icon associated with this item. This icon will not always be shown, so
the title should be sufficient in describing this item. -->
<attr name="icon" format="integer" />
<!-- The alphabetic shortcut key. This is the shortcut when using a keyboard
with alphabetic keys. -->
<attr name="alphabeticShortcut" format="string" />
<!-- The numeric shortcut key. This is the shortcut when using a numeric (e.g., 12-key)
keyboard. -->
<attr name="numericShortcut" format="string" />
<!-- Whether the item is capable of displaying a check mark. -->
<attr name="checkable" format="boolean" />
<!-- Name of a method on the Context used to inflate the menu that will be
called when the item is clicked. -->
<attr name="onClick" format="string" />
<!-- How this item should display in the Action Bar, if present. -->
<attr name="showAsAction">
<!-- Never show this item in an action bar, show it in the overflow menu instead.
Mutually exclusive with "ifRoom" and "always". -->
<flag name="never" value="0" />
<!-- Show this item in an action bar if there is room for it as determined
by the system. Favor this option over "always" where possible.
Mutually exclusive with "never" and "always". -->
<flag name="ifRoom" value="1" />
<!-- Always show this item in an actionbar, even if it would override
the system's limits of how much stuff to put there. This may make
your action bar look bad on some screens. In most cases you should
use "ifRoom" instead. Mutually exclusive with "ifRoom" and "never". -->
<flag name="always" value="2" />
<!-- When this item is shown as an action in the action bar, show a text
label with it even if it has an icon representation. -->
<flag name="withText" value="4" />
<!-- This item's action view collapses to a normal menu
item. When expanded, the action view takes over a
larger segment of its container. -->
<flag name="collapseActionView" value="8" />
</attr>
<!-- An optional layout to be used as an action view.
See {@link android.view.MenuItem#setActionView(android.view.View)}
for more info. -->
<attr name="actionLayout" format="reference" />
<!-- The name of an optional View class to instantiate and use as an
action view. See {@link android.view.MenuItem#setActionView(android.view.View)}
for more info. -->
<attr name="actionViewClass" format="string" />
<!-- The name of an optional ActionProvider class to instantiate an action view
and perform operations such as default action for that menu item. -->
<attr name="actionProviderClass" format="string" />
</declare-styleable>
</resources>
然后我使用以下代码访问了图标resID：
ArrayList<Integer> iconList = new ArrayList<Integer>();
CustomMenuInflater menuInf = new CustomMenuInflater(this);
menuInf.inflate(R.menu.detail_menu, iconList);
menu.xml必须包含xmlns:android="http://schemas.android.com/apk/res-auto"而不是xmlns:android="http://schemas.android.com/apk/res/android"。
更新：我将菜单文件更改为具有两个名称空间，并为每个名称空间重复图标行，以使图标同时显示在帮助画布和ActionBar中。
<?xml version="1.0" encoding="utf-8"?>
<menu xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:myapp="http://schemas.android.com/apk/res-auto" >
<item android:id="@+id/activity_detail_save"
android:icon="@drawable/ic_action_save"
myapp:icon="@drawable/ic_action_save"
android:title="@string/save"
android:showAsAction="ifRoom" />
<item android:id="@+id/activity_detail_delete"
android:icon="@drawable/ic_action_delete"
myapp:icon="@drawable/ic_action_delete"
android:title="@string/delete"
android:showAsAction="ifRoom" />
<item android:id="@+id/activity_detail_help"
android:icon="@drawable/ic_action_help"
myapp:icon="@drawable/ic_action_help"
android:title="@string/help"
android:showAsAction="ifRoom" />
</menu>