Fat*_*tie 4 html markdown nsattributedstring swift
我想将NSAttributedString转换为html,如下所示:
This is a <i>string</i> with some <b>simple</b> <i><b>html</b></i> tags in it.
不幸的是,如果你使用apple的内置系统,它会生成详细的基于CSS的html.(以下示例供参考)
那么如何从NSAttributedString生成简单的标记html？
我写了一篇非常详细,脆弱的电话来做这件事,这是一个糟糕的解决方案.
func simpleTagStyle(fromNSAttributedString att: NSAttributedString)->String {
// verbose, fragile solution
// essentially, iterate all the attribute ranges in the attString
// make a note of what style they are, bold italic etc
// (totally ignore any not of interest to us)
// then basically get the plain string, and munge it for those ranges.
// be careful with the annoying "multiple attribute" case
// (an alternative would be to repeatedly munge out attributed ranges
// one by one until there are none left.)
let rangeAll = NSRange(location: 0, length: att.length)
// make a note of all of the ranges of bold/italic
// (use a tuple to remember which is which)
var allBlocks: [(NSRange, String)] = []
att.enumerateAttribute(
NSFontAttributeName,
in: rangeAll,
options: .longestEffectiveRangeNotRequired
)
{ value, range, stop in
handler: if let font = value as? UIFont {
let b = font.fontDescriptor.symbolicTraits.contains(.traitBold)
let i = font.fontDescriptor.symbolicTraits.contains(.traitItalic)
if b && i {
allBlocks.append( (range, "bolditalic") )
break handler // take care not to duplicate
}
if b {
allBlocks.append( (range, "bold") )
break handler
}
if i {
allBlocks.append( (range, "italic") )
break handler
}
}
}
// traverse those backwards and munge away
var plainString = att.string
for oneBlock in allBlocks.reversed() {
let r = oneBlock.0.range(for: plainString)!
let w = plainString.substring(with: r)
if oneBlock.1 == "bolditalic" {
plainString.replaceSubrange(r, with: "<b><i>" + w + "</i></b>")
}
if oneBlock.1 == "bold" {
plainString.replaceSubrange(r, with: "<b>" + w + "</b>")
}
if oneBlock.1 == "italic" {
plainString.replaceSubrange(r, with: "<i>" + w + "</i>")
}
}
return plainString
}
所以这里是如何使用Apple的内置系统,不幸的是生成全面的CSS等.
x = ... your NSAttributedText
var resultHtmlText = ""
do {
let r = NSRange(location: 0, length: x.length)
let att = [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType]
let d = try x.data(from: r, documentAttributes: att)
if let h = String(data: d, encoding: .utf8) {
resultHtmlText = h
}
}
catch {
print("utterly failed to convert to html!!! \n>\(x)<\n")
}
print(resultHtmlText)
示例输出....
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01//EN" "http://www.w3.org/TR/html4/strict.dtd">
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=UTF-8">
<meta http-equiv="Content-Style-Type" content="text/css">
<title></title>
<meta name="Generator" content="Cocoa HTML Writer">
<style type="text/css">
p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px 'Some Font'}
span.s1 {font-family: 'SomeFont-ItalicOrWhatever'; font-weight: normal; font-style: normal; font-size: 14.00pt}
span.s2 {font-family: 'SomeFont-SemiboldItalic'; font-weight: bold; font-style: italic; font-size: 14.00pt}
</style>
</head>
<body>
<p class="p1"><span class="s1">So, </span><span class="s2">here is</span><span class="s1"> some</span> stuff</p>
</body>
</html>
根据文件enumerateAttribute:inRange:options:usingBlock:,尤其是讨论部分,其中指出:
如果将此方法发送到NSMutableAttributedString的实例,则允许变异(删除,添加或更改),只要它在提供给块的范围内; 在突变之后,在针对突变调整处理范围的长度之后,枚举继续紧接在处理范围之后的范围.(枚举器基本上假设长度的任何变化都发生在指定的范围内.)例如,如果调用块的位置从位置N开始,并且该块删除了所提供范围内的所有字符,则下一个调用也将通过N.作为范围的指数.
换句话说,在闭包/块中,使用range,可以删除/替换那里的字符.操作系统会在该范围的末端放置一个标记.完成修改后,它将计算标记新范围,以便枚举的下一次迭代将从该新标记开始.因此,您不必将所有范围保留在数组中,然后通过执行向后替换来应用更改,而不是修改范围.不要打扰你,方法已经做到了.
我不是Swift开发者,我更像是Objective-C.所以我的Swift代码可能不会尊重所有"Swift规则",并且可能有点丑陋(可选,包装等,做得不好,if let没做过,等等)
这是我的解决方案:
func attrStrSimpleTag() -> Void {
let htmlStr = "<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01//EN\" \"http://www.w3.org/TR/html4/strict.dtd\"> <html> <head> <meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\"> <meta http-equiv=\"Content-Style-Type\" content=\"text/css\"> <title></title> <meta name=\"Generator\" content=\"Cocoa HTML Writer\"> <style type=\"text/css\"> p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px 'Some Font'} span.s1 {font-family: 'SomeFont-ItalicOrWhatever'; font-weight: normal; font-style: normal; font-size: 14.00pt} span.s2 {font-family: 'SomeFont-SemiboldItalic'; font-weight: bold; font-style: italic; font-size: 14.00pt} </style> </head> <body> <p class=\"p1\"><span class=\"s1\">So, </span><span class=\"s2\">here is</span><span class=\"s1\"> some</span> stuff</p> </body></html>"
let attr = try! NSMutableAttributedString.init(data: htmlStr.data(using: .utf8)!,
options: [NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType],
documentAttributes: nil)
print("Attr: \(attr)")
attr.enumerateAttribute(NSFontAttributeName, in: NSRange.init(location: 0, length: attr.length), options: []) { (value, range, stop) in
if let font = value as? UIFont {
print("font found:\(font)")
let isBold = font.fontDescriptor.symbolicTraits.contains(.traitBold)
let isItalic = font.fontDescriptor.symbolicTraits.contains(.traitItalic)
let occurence = attr.attributedSubstring(from: range).string
let replacement = self.formattedString(initialString: occurence, bold: isBold, italic: isItalic)
attr.replaceCharacters(in: range, with: replacement)
}
};
let taggedString = attr.string
print("taggedString: \(taggedString)")
}
func formattedString(initialString:String, bold: Bool, italic: Bool) -> String {
var retString = initialString
if bold {
retString = "<b>".appending(retString)
retString.append("</b>")
}
if italic
{
retString = "<i>".appending(retString)
retString.append("</i>")
}
return retString
}
输出(对于最后一个,其他两个打印仅用于调试):
$> taggedString: So, <i><b>here is</b></i> some stuff
编辑: Objective-C版本(快速编写,可能是一些问题).
-(void)attrStrSimpleTag
{
NSString *htmlStr = @"<!DOCTYPE html PUBLIC \"-//W3C//DTD HTML 4.01//EN\" \"http://www.w3.org/TR/html4/strict.dtd\"> <html> <head> <meta http-equiv=\"Content-Type\" content=\"text/html; charset=UTF-8\"> <meta http-equiv=\"Content-Style-Type\" content=\"text/css\"> <title></title> <meta name=\"Generator\" content=\"Cocoa HTML Writer\"> <style type=\"text/css\"> p.p1 {margin: 0.0px 0.0px 0.0px 0.0px; font: 14.0px 'Some Font'} span.s1 {font-family: 'SomeFont-ItalicOrWhatever'; font-weight: normal; font-style: normal; font-size: 14.00pt} span.s2 {font-family: 'SomeFont-SemiboldItalic'; font-weight: bold; font-style: italic; font-size: 14.00pt} </style> </head> <body> <p class=\"p1\"><span class=\"s1\">So, </span><span class=\"s2\">here is</span><span class=\"s1\"> some</span> stuff</p> </body></html>";
NSMutableAttributedString *attr = [[NSMutableAttributedString alloc] initWithData:[htmlStr dataUsingEncoding:NSUTF8StringEncoding]
options:@{NSDocumentTypeDocumentAttribute: NSHTMLTextDocumentType}
documentAttributes:nil
error:nil];
NSLog(@"Attr: %@", attr);
[attr enumerateAttribute:NSFontAttributeName inRange:NSMakeRange(0, [attr length]) options:0 usingBlock:^(id _Nullable value, NSRange range, BOOL * _Nonnull stop) {
UIFont *font = (UIFont *)value;
NSLog(@"Font found: %@", font);
BOOL isBold = UIFontDescriptorTraitBold & [[font fontDescriptor] symbolicTraits];
BOOL isItalic = UIFontDescriptorTraitItalic & [[font fontDescriptor] symbolicTraits];
NSString *occurence = [[attr attributedSubstringFromRange:range] string];
NSString *replacement = [self formattedStringWithString:occurence isBold:isBold andItalic:isItalic];
[attr replaceCharactersInRange:range withString:replacement];
}];
NSString *taggedString = [attr string];
NSLog(@"taggedString: %@", taggedString);
}
-(NSString *)formattedStringWithString:(NSString *)string isBold:(BOOL)isBold andItalic:(BOOL)isItalic
{
NSString *retString = string;
if (isBold)
{
retString = [NSString stringWithFormat:@"<b>%@</b>", retString];
}
if (isItalic)
{
retString = [NSString stringWithFormat:@"<i>%@</i>", retString];
}
return retString;
}