Convert attributed string, to, “simple” tagged html
I want to convert an NSAttributedString, to html like this:
This is a string with some simple html<
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I have good way to convert NSAttributedString into simple HTML string .
1) Take UIWebView and UITextView.
2) Set your Attributed string in WebView.
[webView loadHTMLString:[yourAttributedString stringByReplacingOccurrencesOfString:@"\n" withString:@"<br/>"] baseURL:nil];3) Get your HTML string from UIWebView.
NSString *simpleHtmlString = [webView stringByEvaluatingJavaScriptFromString:@"document.body.innerHTML"];讨论(0) -
Here's a more complete solution that preserves more styles and links.
Check out the other keys in NSAttributedString.h if you want to preserve color and kerning information.
@implementation NSAttributedString (SimpleHTML) - (NSString*) simpleHTML { NSMutableAttributedString* attr = [self mutableCopy]; [attr enumerateAttributesInRange: NSMakeRange(0, [self length]) options: 0 usingBlock: ^(NSDictionary<NSAttributedStringKey,id> * _Nonnull attrs, NSRange range, BOOL * _Nonnull stop) { for (NSString* aKey in attrs.allKeys.copy) { NSString* format = nil; if ([aKey compare: NSFontAttributeName] == NSOrderedSame) //UIFont, default Helvetica(Neue) 12 { UIFont* font = attrs[aKey]; BOOL isBold = UIFontDescriptorTraitBold & [[font fontDescriptor] symbolicTraits]; BOOL isItalic = UIFontDescriptorTraitItalic & [[font fontDescriptor] symbolicTraits]; if (isBold && isItalic) { format = @"<b><i>%@</i></b>"; } else if (isBold) { format = @"<b>%@</b>"; } else if (isItalic) { format = @"<i>%@</i>"; } } else if ([aKey compare: NSStrikethroughStyleAttributeName] == NSOrderedSame) //NSNumber containing integer, default 0: no strikethrough { NSNumber* strike = (id) attrs[aKey]; if (strike.boolValue) { format = @"<strike>"; } else { format = @"</strike>"; } } else if ([aKey compare: NSUnderlineStyleAttributeName] == NSOrderedSame) //NSNumber containing integer, default 0: no underline { if ([attrs.allKeys containsObject: NSLinkAttributeName] == NO) { NSNumber* underline = (id) attrs[aKey]; if (underline.boolValue) { format = @"<u>%@</u>"; } } } else if ([aKey compare: NSLinkAttributeName] == NSOrderedSame) //NSURL (preferred) or NSString { NSObject* value = (id) attrs[aKey]; NSString* absolute = @""; if ([value isKindOfClass: NSURL.class]) { NSURL* url = (id) value; absolute = url.absoluteString; } else if ([value isKindOfClass: NSString.class]) { absolute = (id) value; } format = [NSString stringWithFormat: @"<a href=\"%@\">%%@</a>", absolute]; } if (format) { NSString* occurence = [[attr attributedSubstringFromRange: range] string]; NSString* replacement = [NSString stringWithFormat: format, occurence]; [attr replaceCharactersInRange: range withString: replacement]; } } }]; NSMutableString* result = [[NSString stringWithFormat: @"<html>%@</html>", attr.string] mutableCopy]; [result replaceOccurrencesOfString: @"\n" withString: @"<br>" options: 0 range: NSMakeRange(0, result.length)]; return result; } @endEDIT: I've added the conditional you need to check to enable/disable underline detection while it's treating a URL.
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According to the documentation of enumerateAttribute:inRange:options:usingBlock:, especially the Discussion part which states:
If this method is sent to an instance of NSMutableAttributedString, mutation (deletion, addition, or change) is allowed, as long as it is within the range provided to the block; after a mutation, the enumeration continues with the range immediately following the processed range, after the length of the processed range is adjusted for the mutation. (The enumerator basically assumes any change in length occurs in the specified range.) For example, if block is called with a range starting at location N, and the block deletes all the characters in the supplied range, the next call will also pass N as the index of the range.
In other words, in the closure/block, with the
range, you can delete/replace characters there. The OS will put a marker on that end of the range. Once you did your modifications, it will compute the marker new range in order that the next iteration of the enumeration will start from that new marker. So you don't have to keep all the ranges in an array and apply the changes afterwards by doing a backward replacement to not modify the range. Don't bother you with that, the methods does it already.I'm not a Swift developper, I'm more an Objective-C one. So my Swift code may not respect all "Swift rules", and may be a little ugly (optionals, wrapping, etc badly done,
if letnot done, etc.)Here is my solution:
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 }Output (for the last one, the other two prints are just for debug):
$> taggedString: So, <i><b>here is</b></i> some stuffEdit: Objective-C Version (quickly written, maybe some issue).
-(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; }Edit Jan. 2020:
Updated code with easier modifications and Swift 5, adding support for two new effects (underline/strikethrough).// MARK: In one loop extension NSMutableAttributedString { func htmlSimpleTagString() -> String { enumerateAttributes(in: fullRange(), options: []) { (attributes, range, pointeeStop) in let occurence = self.attributedSubstring(from: range).string var replacement: String = occurence if let font = attributes[.font] as? UIFont { replacement = self.font(initialString: replacement, fromFont: font) } if let underline = attributes[.underlineStyle] as? Int { replacement = self.underline(text: replacement, fromStyle: underline) } if let striked = attributes[.strikethroughStyle] as? Int { replacement = self.strikethrough(text: replacement, fromStyle: striked) } self.replaceCharacters(in: range, with: replacement) } return self.string } } // MARK: In multiple loop extension NSMutableAttributedString { func htmlSimpleTagString(options: [NSAttributedString.Key]) -> String { if options.contains(.underlineStyle) { enumerateAttribute(.underlineStyle, in: fullRange(), options: []) { (value, range, pointeeStop) in let occurence = self.attributedSubstring(from: range).string guard let style = value as? Int else { return } if NSUnderlineStyle(rawValue: style) == NSUnderlineStyle.styleSingle { let replacement = self.underline(text: occurence, fromStyle: style) self.replaceCharacters(in: range, with: replacement) } } } if options.contains(.strikethroughStyle) { enumerateAttribute(.strikethroughStyle, in: fullRange(), options: []) { (value, range, pointeeStop) in let occurence = self.attributedSubstring(from: range).string guard let style = value as? Int else { return } let replacement = self.strikethrough(text: occurence, fromStyle: style) self.replaceCharacters(in: range, with: replacement) } } if options.contains(.font) { enumerateAttribute(.font, in: fullRange(), options: []) { (value, range, pointeeStop) in let occurence = self.attributedSubstring(from: range).string guard let font = value as? UIFont else { return } let replacement = self.font(initialString: occurence, fromFont: font) self.replaceCharacters(in: range, with: replacement) } } return self.string } } //MARK: Replacing extension NSMutableAttributedString { func font(initialString: String, fromFont font: UIFont) -> String { let isBold = font.fontDescriptor.symbolicTraits.contains(.traitBold) let isItalic = font.fontDescriptor.symbolicTraits.contains(.traitItalic) var retString = initialString if isBold { retString = "<b>" + retString + "</b>" } if isItalic { retString = "<i>" + retString + "</i>" } return retString } func underline(text: String, fromStyle style: Int) -> String { return "<u>" + text + "</u>" } func strikethrough(text: String, fromStyle style: Int) -> String { return "<s>" + text + "</s>" } } //MARK: Utility extension NSAttributedString { func fullRange() -> NSRange { return NSRange(location: 0, length: self.length) } }Simple HTML to test with mixed tags:
"This is <i>ITALIC</i> with some <b>BOLD</b> <b><i>BOLDandITALIC</b></i> <b>BOLD<u>UNDERLINEandBOLD</b>RESTUNDERLINE</u> in it."The solutions brings two approaches: One doing one loop, the other doing multiple loops, but for mixed tags, the result could be strange. Check with the sample provided previously the different rendering.
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