很久没上51CTO了，谢谢一些最近心得，能够看到文本中的字符串“这里”带了超链接，点击链接后，Android中的TextView，本身就支持部分的Html格式标签。这其中包括常用的字体大小颜色设置，文本链接等。使用起来也比较方便，只需要使用Html类转换一下即可。比如：

textView.setText(Html.fromHtml(str));


然而，有一种场合，默认支持的标签可能不够用。比如，我们需要在textView中点击某种链接，返回到应用中的某个界面，而不仅仅是网络连接，如何实现？


经过几个小时对android中的Html类源代码的研究，找到了解决办法，并且测试通过。


先看Html类的源代码中有这样一段：

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/**
* 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);
/**
* 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);
}

这里定义了一个接口，接口用于什么呢？

再继续看代码，看到对Html的tag进行解析部分的代码：

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private void handleStartTag(String tag, Attributes attributes) {
if (tag.equalsIgnoreCase("br")) {
// We don't need to handle this. TagSoup will ensure that there's a </br> for each <br>
// so we can safely emite the linebreaks when we handle the close tag.
} else if (tag.equalsIgnoreCase("p")) {
handleP(mSpannableStringBuilder);
} else if (tag.equalsIgnoreCase("div")) {
handleP(mSpannableStringBuilder);
} else if (tag.equalsIgnoreCase("em")) {
start(mSpannableStringBuilder, new Bold());
} else if (tag.equalsIgnoreCase("b")) {
start(mSpannableStringBuilder, new Bold());
} else if (tag.equalsIgnoreCase("strong")) {
start(mSpannableStringBuilder, new Italic());
} else if (tag.equalsIgnoreCase("cite")) {
start(mSpannableStringBuilder, new Italic());
} else if (tag.equalsIgnoreCase("dfn")) {
start(mSpannableStringBuilder, new Italic());
} else if (tag.equalsIgnoreCase("i")) {
start(mSpannableStringBuilder, new Italic());
} else if (tag.equalsIgnoreCase("big")) {
start(mSpannableStringBuilder, new Big());
} else if (tag.equalsIgnoreCase("small")) {
start(mSpannableStringBuilder, new Small());
} else if (tag.equalsIgnoreCase("font")) {
startFont(mSpannableStringBuilder, attributes);
} else if (tag.equalsIgnoreCase("blockquote")) {
handleP(mSpannableStringBuilder);
start(mSpannableStringBuilder, new Blockquote());
} else if (tag.equalsIgnoreCase("tt")) {
start(mSpannableStringBuilder, new Monospace());
} else if (tag.equalsIgnoreCase("a")) {
startA(mSpannableStringBuilder, attributes);
} else if (tag.equalsIgnoreCase("u")) {
start(mSpannableStringBuilder, new Underline());
} else if (tag.equalsIgnoreCase("sup")) {
start(mSpannableStringBuilder, new Super());
} else if (tag.equalsIgnoreCase("sub")) {
start(mSpannableStringBuilder, new Sub());
} else if (tag.length() == 2 &&
Character.toLowerCase(tag.charAt(0)) == 'h' &&
tag.charAt(1) >= '1' && tag.charAt(1) <= '6') {
handleP(mSpannableStringBuilder);
start(mSpannableStringBuilder, new Header(tag.charAt(1) - '1'));
} else if (tag.equalsIgnoreCase("img")) {
startImg(mSpannableStringBuilder, attributes, mImageGetter);
} else if (mTagHandler != null) {
mTagHandler.handleTag(true, tag, mSpannableStringBuilder, mReader);
}
}

private void handleEndTag(String tag) {
if (tag.equalsIgnoreCase("br")) {
handleBr(mSpannableStringBuilder);
} else if (tag.equalsIgnoreCase("p")) {
handleP(mSpannableStringBuilder);
} else if (tag.equalsIgnoreCase("div")) {
handleP(mSpannableStringBuilder);
} else if (tag.equalsIgnoreCase("em")) {
end(mSpannableStringBuilder, Bold.class, new StyleSpan(Typeface.BOLD));
} else if (tag.equalsIgnoreCase("b")) {
end(mSpannableStringBuilder, Bold.class, new StyleSpan(Typeface.BOLD));
} else if (tag.equalsIgnoreCase("strong")) {
end(mSpannableStringBuilder, Italic.class, new StyleSpan(Typeface.ITALIC));
} else if (tag.equalsIgnoreCase("cite")) {
end(mSpannableStringBuilder, Italic.class, new StyleSpan(Typeface.ITALIC));
} else if (tag.equalsIgnoreCase("dfn")) {
end(mSpannableStringBuilder, Italic.class, new StyleSpan(Typeface.ITALIC));
} else if (tag.equalsIgnoreCase("i")) {
end(mSpannableStringBuilder, Italic.class, new StyleSpan(Typeface.ITALIC));
} else if (tag.equalsIgnoreCase("big")) {
end(mSpannableStringBuilder, Big.class, new RelativeSizeSpan(1.25f));
} else if (tag.equalsIgnoreCase("small")) {
end(mSpannableStringBuilder, Small.class, new RelativeSizeSpan(0.8f));
} else if (tag.equalsIgnoreCase("font")) {
endFont(mSpannableStringBuilder);
} else if (tag.equalsIgnoreCase("blockquote")) {
handleP(mSpannableStringBuilder);
end(mSpannableStringBuilder, Blockquote.class, new QuoteSpan());
} else if (tag.equalsIgnoreCase("tt")) {
end(mSpannableStringBuilder, Monospace.class,
new TypefaceSpan("monospace"));
} else if (tag.equalsIgnoreCase("a")) {
endA(mSpannableStringBuilder);
} else if (tag.equalsIgnoreCase("u")) {
end(mSpannableStringBuilder, Underline.class, new UnderlineSpan());
} else if (tag.equalsIgnoreCase("sup")) {
end(mSpannableStringBuilder, Super.class, new SuperscriptSpan());
} else if (tag.equalsIgnoreCase("sub")) {
end(mSpannableStringBuilder, Sub.class, new SubscriptSpan());
} else if (tag.length() == 2 &&
Character.toLowerCase(tag.charAt(0)) == 'h' &&
tag.charAt(1) >= '1' && tag.charAt(1) <= '6') {
handleP(mSpannableStringBuilder);
endHeader(mSpannableStringBuilder);
} else if (mTagHandler != null) {
mTagHandler.handleTag(false, tag, mSpannableStringBuilder, mReader);
}
}
private void handleStartTag(String tag, Attributes attributes) {
if (tag.equalsIgnoreCase("br")) {
// We don't need to handle this. TagSoup will ensure that there's a </br> for each <br>
// so we can safely emite the linebreaks when we handle the close tag.
} else if (tag.equalsIgnoreCase("p")) {
handleP(mSpannableStringBuilder);
} else if (tag.equalsIgnoreCase("div")) {
handleP(mSpannableStringBuilder);
} else if (tag.equalsIgnoreCase("em")) {
start(mSpannableStringBuilder, new Bold());
} else if (tag.equalsIgnoreCase("b")) {
start(mSpannableStringBuilder, new Bold());
} else if (tag.equalsIgnoreCase("strong")) {
start(mSpannableStringBuilder, new Italic());
} else if (tag.equalsIgnoreCase("cite")) {
start(mSpannableStringBuilder, new Italic());
} else if (tag.equalsIgnoreCase("dfn")) {
start(mSpannableStringBuilder, new Italic());
} else if (tag.equalsIgnoreCase("i")) {
start(mSpannableStringBuilder, new Italic());
} else if (tag.equalsIgnoreCase("big")) {
start(mSpannableStringBuilder, new Big());
} else if (tag.equalsIgnoreCase("small")) {
start(mSpannableStringBuilder, new Small());
} else if (tag.equalsIgnoreCase("font")) {
startFont(mSpannableStringBuilder, attributes);
} else if (tag.equalsIgnoreCase("blockquote")) {
handleP(mSpannableStringBuilder);
start(mSpannableStringBuilder, new Blockquote());
} else if (tag.equalsIgnoreCase("tt")) {
start(mSpannableStringBuilder, new Monospace());
} else if (tag.equalsIgnoreCase("a")) {
startA(mSpannableStringBuilder, attributes);
} else if (tag.equalsIgnoreCase("u")) {
start(mSpannableStringBuilder, new Underline());
} else if (tag.equalsIgnoreCase("sup")) {
start(mSpannableStringBuilder, new Super());
} else if (tag.equalsIgnoreCase("sub")) {
start(mSpannableStringBuilder, new Sub());
} else if (tag.length() == 2 &&
Character.toLowerCase(tag.charAt(0)) == 'h' &&
tag.charAt(1) >= '1' && tag.charAt(1) <= '6') {
handleP(mSpannableStringBuilder);
start(mSpannableStringBuilder, new Header(tag.charAt(1) - '1'));
} else if (tag.equalsIgnoreCase("img")) {
startImg(mSpannableStringBuilder, attributes, mImageGetter);
} else if (mTagHandler != null) {
mTagHandler.handleTag(true, tag, mSpannableStringBuilder, mReader);
}
}

private void handleEndTag(String tag) {
if (tag.equalsIgnoreCase("br")) {
handleBr(mSpannableStringBuilder);
} else if (tag.equalsIgnoreCase("p")) {
handleP(mSpannableStringBuilder);
} else if (tag.equalsIgnoreCase("div")) {
handleP(mSpannableStringBuilder);
} else if (tag.equalsIgnoreCase("em")) {
end(mSpannableStringBuilder, Bold.class, new StyleSpan(Typeface.BOLD));
} else if (tag.equalsIgnoreCase("b")) {
end(mSpannableStringBuilder, Bold.class, new StyleSpan(Typeface.BOLD));
} else if (tag.equalsIgnoreCase("strong")) {
end(mSpannableStringBuilder, Italic.class, new StyleSpan(Typeface.ITALIC));
} else if (tag.equalsIgnoreCase("cite")) {
end(mSpannableStringBuilder, Italic.class, new StyleSpan(Typeface.ITALIC));
} else if (tag.equalsIgnoreCase("dfn")) {
end(mSpannableStringBuilder, Italic.class, new StyleSpan(Typeface.ITALIC));
} else if (tag.equalsIgnoreCase("i")) {
end(mSpannableStringBuilder, Italic.class, new StyleSpan(Typeface.ITALIC));
} else if (tag.equalsIgnoreCase("big")) {
end(mSpannableStringBuilder, Big.class, new RelativeSizeSpan(1.25f));
} else if (tag.equalsIgnoreCase("small")) {
end(mSpannableStringBuilder, Small.class, new RelativeSizeSpan(0.8f));
} else if (tag.equalsIgnoreCase("font")) {
endFont(mSpannableStringBuilder);
} else if (tag.equalsIgnoreCase("blockquote")) {
handleP(mSpannableStringBuilder);
end(mSpannableStringBuilder, Blockquote.class, new QuoteSpan());
} else if (tag.equalsIgnoreCase("tt")) {
end(mSpannableStringBuilder, Monospace.class,
new TypefaceSpan("monospace"));
} else if (tag.equalsIgnoreCase("a")) {
endA(mSpannableStringBuilder);
} else if (tag.equalsIgnoreCase("u")) {
end(mSpannableStringBuilder, Underline.class, new UnderlineSpan());
} else if (tag.equalsIgnoreCase("sup")) {
end(mSpannableStringBuilder, Super.class, new SuperscriptSpan());
} else if (tag.equalsIgnoreCase("sub")) {
end(mSpannableStringBuilder, Sub.class, new SubscriptSpan());
} else if (tag.length() == 2 &&
Character.toLowerCase(tag.charAt(0)) == 'h' &&
tag.charAt(1) >= '1' && tag.charAt(1) <= '6') {
handleP(mSpannableStringBuilder);
endHeader(mSpannableStringBuilder);
} else if (mTagHandler != null) {
mTagHandler.handleTag(false, tag, mSpannableStringBuilder, mReader);
}
}

可以看到，如果不是默认的标签，会调用mTagHandler的handleTag方法。所以，我们可以实现此接口，来解析自己定义的标签类型。

再看一段我实现的对<game>标签进行解析的示例代码：

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public class GameTagHandler implements TagHandler {

private int startIndex = 0;

private int stopIndex = 0;

@Override
public void handleTag(boolean opening, String tag, Editable output,
XMLReader xmlReader) {
if (tag.toLowerCase().equals("game")) {
if (opening) {
startGame(tag, output, xmlReader);
} else {
endGame(tag, output, xmlReader);
}
}

}

public void startGame(String tag, Editable output, XMLReader xmlReader) {
startIndex = output.length();
}

public void endGame(String tag, Editable output, XMLReader xmlReader) {
stopIndex = output.length();
output.setSpan(new GameSpan(), startIndex, stopIndex,
Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
}


private class GameSpan extends ClickableSpan implements OnClickListener {

@Override
public void onClick(View v) {
// 跳转某页面
}
}
public class GameTagHandler implements TagHandler {

private int startIndex = 0;

private int stopIndex = 0;

@Override
public void handleTag(boolean opening, String tag, Editable output,
XMLReader xmlReader) {
if (tag.toLowerCase().equals("game")) {
if (opening) {
startGame(tag, output, xmlReader);
} else {
endGame(tag, output, xmlReader);
}
}

}

public void startGame(String tag, Editable output, XMLReader xmlReader) {
startIndex = output.length();
}

public void endGame(String tag, Editable output, XMLReader xmlReader) {
stopIndex = output.length();
output.setSpan(new GameSpan(), startIndex, stopIndex,
Spanned.SPAN_EXCLUSIVE_EXCLUSIVE);
}


private class GameSpan extends ClickableSpan implements OnClickListener {

@Override
public void onClick(View v) {
// 跳转某页面
}
}

上面这段代码，是对<game>…</game>的自定义标签进行解析。

具体调用方法：

textView.setText(Html.fromHtml(“点击<game>这里</game>跳转到游戏”,

null, new GameTagHandler()));

textView.setClickable(true);

textView.setMovementMethod(LinkMovementMethod.getInstance());

运行后，能够看到文本中的字符串“这里”带了超链接，点击链接后，GameSpan类的onClick()方法被调用。就可以在这个方法中进行跳转了。

本文出自 “飞鸽传书,飞鸽传书2012..” 博客，谢绝转载！

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