Android example source code file (Html.java)
The Html.java Android example source code/*
* 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.text;
import org.ccil.cowan.tagsoup.HTMLSchema;
import org.ccil.cowan.tagsoup.Parser;
import org.xml.sax.Attributes;
import org.xml.sax.ContentHandler;
import org.xml.sax.InputSource;
import org.xml.sax.Locator;
import org.xml.sax.SAXException;
import org.xml.sax.XMLReader;
import android.content.res.ColorStateList;
import android.content.res.Resources;
import android.graphics.Typeface;
import android.graphics.drawable.Drawable;
import android.text.style.AbsoluteSizeSpan;
import android.text.style.AlignmentSpan;
import android.text.style.CharacterStyle;
import android.text.style.ForegroundColorSpan;
import android.text.style.ImageSpan;
import android.text.style.ParagraphStyle;
import android.text.style.QuoteSpan;
import android.text.style.RelativeSizeSpan;
import android.text.style.StrikethroughSpan;
import android.text.style.StyleSpan;
import android.text.style.SubscriptSpan;
import android.text.style.SuperscriptSpan;
import android.text.style.TextAppearanceSpan;
import android.text.style.TypefaceSpan;
import android.text.style.URLSpan;
import android.text.style.UnderlineSpan;
import android.util.Log;
import com.android.internal.util.XmlUtils;
import java.io.IOException;
import java.io.StringReader;
import java.nio.CharBuffer;
import java.util.HashMap;
/**
* This class processes HTML strings into displayable styled text.
* Not all HTML tags are supported.
*/
public class Html {
/**
* Retrieves images for HTML <img> tags.
*/
public static interface ImageGetter {
/**
* This methos is called when the HTML parser encounters an
* <img> tag. The <code>source argument is the
* string from the "src" attribute; the return value should be
* a Drawable representation of the image or <code>null
* for a generic replacement image. Make sure you call
* setBounds() on your Drawable if it doesn't already have
* its bounds set.
*/
public Drawable getDrawable(String source);
}
/**
* Is notified when HTML tags are encountered that the parser does
* not know how to interpret.
*/
public static interface TagHandler {
/**
* This method will be called whenn the HTML parser encounters
* a tag that it does not know how to interpret.
*/
public void handleTag(boolean opening, String tag,
Editable output, XMLReader xmlReader);
}
private Html() { }
/**
* Returns displayable styled text from the provided HTML string.
* Any <img> tags in the HTML will display as a generic
* replacement image which your program can then go through and
* replace with real images.
*
* <p>This uses TagSoup to handle real HTML, including all of the brokenness found in the wild.
*/
public static Spanned fromHtml(String source) {
return fromHtml(source, null, null);
}
/**
* Lazy initialization holder for HTML parser. This class will
* a) be preloaded by the zygote, or b) not loaded until absolutely
* necessary.
*/
private static class HtmlParser {
private static final HTMLSchema schema = new HTMLSchema();
}
/**
* Returns displayable styled text from the provided HTML string.
* Any <img> tags in the HTML will use the specified ImageGetter
* to request a representation of the image (use null if you don't
* want this) and the specified TagHandler to handle unknown tags
* (specify null if you don't want this).
*
* <p>This uses TagSoup to handle real HTML, including all of the brokenness found in the wild.
*/
public static Spanned fromHtml(String source, ImageGetter imageGetter,
TagHandler tagHandler) {
Parser parser = new Parser();
try {
parser.setProperty(Parser.schemaProperty, HtmlParser.schema);
} catch (org.xml.sax.SAXNotRecognizedException e) {
// Should not happen.
throw new RuntimeException(e);
} catch (org.xml.sax.SAXNotSupportedException e) {
// Should not happen.
throw new RuntimeException(e);
}
HtmlToSpannedConverter converter =
new HtmlToSpannedConverter(source, imageGetter, tagHandler,
parser);
return converter.convert();
}
/**
* Returns an HTML representation of the provided Spanned text.
*/
public static String toHtml(Spanned text) {
StringBuilder out = new StringBuilder();
withinHtml(out, text);
return out.toString();
}
private static void withinHtml(StringBuilder out, Spanned text) {
int len = text.length();
int next;
for (int i = 0; i < text.length(); i = next) {
next = text.nextSpanTransition(i, len, ParagraphStyle.class);
ParagraphStyle[] style = text.getSpans(i, next, ParagraphStyle.class);
String elements = " ";
boolean needDiv = false;
for(int j = 0; j < style.length; j++) {
if (style[j] instanceof AlignmentSpan) {
Layout.Alignment align =
((AlignmentSpan) style[j]).getAlignment();
needDiv = true;
if (align == Layout.Alignment.ALIGN_CENTER) {
elements = "align=\"center\" " + elements;
} else if (align == Layout.Alignment.ALIGN_OPPOSITE) {
elements = "align=\"right\" " + elements;
} else {
elements = "align=\"left\" " + elements;
}
}
}
if (needDiv) {
out.append("<div " + elements + ">");
}
withinDiv(out, text, i, next);
if (needDiv) {
out.append("</div>");
}
}
}
private static void withinDiv(StringBuilder out, Spanned text,
int start, int end) {
int next;
for (int i = start; i < end; i = next) {
next = text.nextSpanTransition(i, end, QuoteSpan.class);
QuoteSpan[] quotes = text.getSpans(i, next, QuoteSpan.class);
for (QuoteSpan quote: quotes) {
out.append("<blockquote>");
}
withinBlockquote(out, text, i, next);
for (QuoteSpan quote: quotes) {
out.append("</blockquote>\n");
}
}
}
private static void withinBlockquote(StringBuilder out, Spanned text,
int start, int end) {
out.append("<p>");
int next;
for (int i = start; i < end; i = next) {
next = TextUtils.indexOf(text, '\n', i, end);
if (next < 0) {
next = end;
}
int nl = 0;
while (next < end && text.charAt(next) == '\n') {
nl++;
next++;
}
withinParagraph(out, text, i, next - nl, nl, next == end);
}
out.append("</p>\n");
}
private static void withinParagraph(StringBuilder out, Spanned text,
int start, int end, int nl,
boolean last) {
int next;
for (int i = start; i < end; i = next) {
next = text.nextSpanTransition(i, end, CharacterStyle.class);
CharacterStyle[] style = text.getSpans(i, next,
CharacterStyle.class);
for (int j = 0; j < style.length; j++) {
if (style[j] instanceof StyleSpan) {
int s = ((StyleSpan) style[j]).getStyle();
if ((s & Typeface.BOLD) != 0) {
out.append("<b>");
}
if ((s & Typeface.ITALIC) != 0) {
out.append("<i>");
}
}
if (style[j] instanceof TypefaceSpan) {
String s = ((TypefaceSpan) style[j]).getFamily();
if (s.equals("monospace")) {
out.append("<tt>");
}
}
if (style[j] instanceof SuperscriptSpan) {
out.append("<sup>");
}
if (style[j] instanceof SubscriptSpan) {
out.append("<sub>");
}
if (style[j] instanceof UnderlineSpan) {
out.append("<u>");
}
if (style[j] instanceof StrikethroughSpan) {
out.append("<strike>");
}
if (style[j] instanceof URLSpan) {
out.append("<a href=\"");
out.append(((URLSpan) style[j]).getURL());
out.append("\">");
}
if (style[j] instanceof ImageSpan) {
out.append("<img src=\"");
out.append(((ImageSpan) style[j]).getSource());
out.append("\">");
// Don't output the dummy character underlying the image.
i = next;
}
if (style[j] instanceof AbsoluteSizeSpan) {
out.append("<font size =\"");
out.append(((AbsoluteSizeSpan) style[j]).getSize() / 6);
out.append("\">");
}
if (style[j] instanceof ForegroundColorSpan) {
out.append("<font color =\"#");
String color = Integer.toHexString(((ForegroundColorSpan)
style[j]).getForegroundColor() + 0x01000000);
while (color.length() < 6) {
color = "0" + color;
}
out.append(color);
out.append("\">");
}
}
withinStyle(out, text, i, next);
for (int j = style.length - 1; j >= 0; j--) {
if (style[j] instanceof ForegroundColorSpan) {
out.append("</font>");
}
if (style[j] instanceof AbsoluteSizeSpan) {
out.append("</font>");
}
if (style[j] instanceof URLSpan) {
out.append("</a>");
}
if (style[j] instanceof StrikethroughSpan) {
out.append("</strike>");
}
if (style[j] instanceof UnderlineSpan) {
out.append("</u>");
}
if (style[j] instanceof SubscriptSpan) {
out.append("</sub>");
}
if (style[j] instanceof SuperscriptSpan) {
out.append("</sup>");
}
if (style[j] instanceof TypefaceSpan) {
String s = ((TypefaceSpan) style[j]).getFamily();
if (s.equals("monospace")) {
out.append("</tt>");
}
}
if (style[j] instanceof StyleSpan) {
int s = ((StyleSpan) style[j]).getStyle();
if ((s & Typeface.BOLD) != 0) {
out.append("</b>");
}
if ((s & Typeface.ITALIC) != 0) {
out.append("</i>");
}
}
}
}
String p = last ? "" : "</p>\n
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