android.util.XML介绍

android为我们提供了一系列的和XML操作相关的方法，这些方法都位于类android.util.XML中，主要方法如下

asAttributeSet()方法：

      将xml中的内容以加载到一个AttributeSet中，以键值对的形式存储。一般被用于描述某个图形表现形式。和android:text这种标签的功能一样。

其他的方法也没什么好解释的了。

这里粘贴处XML类的源代码，对于其实现过程就一目了然了、

 

 

 

 /* * Copyright (C) 2007 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.util; import org.xml.sax.ContentHandler; import org.xml.sax.InputSource; import org.xml.sax.SAXException; import org.xml.sax.XMLReader; import org.xmlpull.v1.XmlPullParser; import org.xmlpull.v1.XmlSerializer; import org.xmlpull.v1.XmlPullParserException; import org.xmlpull.v1.XmlPullParserFactory; import java.io.IOException; import java.io.InputStream; import java.io.Reader; import java.io.StringReader; import java.io.UnsupportedEncodingException; import org.apache.harmony.xml.ExpatPullParser; import org.apache.harmony.xml.ExpatReader; /** * XML utility methods. */ public class Xml { /** * {@link org.xmlpull.v1.XmlPullParser} "relaxed" feature name. * * @see <a href="http://xmlpull.org/v1/doc/features.html#relaxed" mce_href="http://xmlpull.org/v1/doc/features.html#relaxed"> * specification</a> */ public static String FEATURE_RELAXED = ExpatPullParser.FEATURE_RELAXED; /** * Parses the given xml string and fires events on the given SAX handler. */ public static void parse(String xml, ContentHandler contentHandler) throws SAXException { try { XMLReader reader = new ExpatReader(); reader.setContentHandler(contentHandler); reader.parse(new InputSource(new StringReader(xml))); } catch (IOException e) { throw new AssertionError(e); } } /** * Parses xml from the given reader and fires events on the given SAX * handler. */ public static void parse(Reader in, ContentHandler contentHandler) throws IOException, SAXException { XMLReader reader = new ExpatReader(); reader.setContentHandler(contentHandler); reader.parse(new InputSource(in)); } /** * Parses xml from the given input stream and fires events on the given SAX * handler. */ public static void parse(InputStream in, Encoding encoding, ContentHandler contentHandler) throws IOException, SAXException { try { XMLReader reader = new ExpatReader(); reader.setContentHandler(contentHandler); InputSource source = new InputSource(in); source.setEncoding(encoding.expatName); reader.parse(source); } catch (IOException e) { throw new AssertionError(e); } } /** * Creates a new pull parser with namespace support. * * <p><b>Note:</b> This is actually slower than the SAX parser, and it's not * fully implemented. If you need a fast, mostly implemented pull parser, * use this. If you need a complete implementation, use KXML. */ public static XmlPullParser newPullParser() { ExpatPullParser parser = new ExpatPullParser(); parser.setNamespaceProcessingEnabled(true); return parser; } /** * Creates a new xml serializer. */ public static XmlSerializer newSerializer() { try { return XmlSerializerFactory.instance.newSerializer(); } catch (XmlPullParserException e) { throw new AssertionError(e); } } /** Factory for xml serializers. Initialized on demand. */ static class XmlSerializerFactory { static final String TYPE = "org.kxml2.io.KXmlParser,org.kxml2.io.KXmlSerializer"; static final XmlPullParserFactory instance; static { try { instance = XmlPullParserFactory.newInstance(TYPE, null); } catch (XmlPullParserException e) { throw new AssertionError(e); } } } /** * Supported character encodings. */ public enum Encoding { US_ASCII("US-ASCII"), UTF_8("UTF-8"), UTF_16("UTF-16"), ISO_8859_1("ISO-8859-1"); final String expatName; Encoding(String expatName) { this.expatName = expatName; } } /** * Finds an encoding by name. Returns UTF-8 if you pass {@code null}. */ public static Encoding findEncodingByName(String encodingName) throws UnsupportedEncodingException { if (encodingName == null) { return Encoding.UTF_8; } for (Encoding encoding : Encoding.values()) { if (encoding.expatName.equalsIgnoreCase(encodingName)) return encoding; } throw new UnsupportedEncodingException(encodingName); } /** * Return an AttributeSet interface for use with the given XmlPullParser. * If the given parser itself implements AttributeSet, that implementation * is simply returned. Otherwise a wrapper class is * instantiated on top of the XmlPullParser, as a proxy for retrieving its * attributes, and returned to you. * * @param parser The existing parser for which you would like an * AttributeSet. * * @return An AttributeSet you can use to retrieve the * attribute values at each of the tags as the parser moves * through its XML document. * * @see AttributeSet */ public static AttributeSet asAttributeSet(XmlPullParser parser) { return (parser instanceof AttributeSet) ? (AttributeSet) parser : new XmlPullAttributes(parser); } }