I'm trying to build a simple note app. At the moment, I'm focusing on the possibility to set the text with different text styles (e.g. body, headline, bold, italic, etc.). I used a NSAttributedString to set the different text styles. Now, I'd like to detect which style has been applied to the selected text.
I thought a good way to do it would have been to create a custom NSAttributedString.Key, so that I can assign it when setting the attributes (e.g. .textStyle: "headline", and read it when I need to detect it. I tried implementing it as an extension of NSAttributedString.Key but without success. What would be the correct way to do it?
Is there a better alternative?
You can simply create a TextStyle enumeration and set your cases "body, headline, bold, italic, etc" (You can assign any value to them if needed). Then you just need to create a new NSAttributedString key:
enum TextStyle {
case body, headline, bold, italic
}
extension NSAttributedString.Key {
static let textStyle: NSAttributedString.Key = .init("textStyle")
}
Playground Testing
let attributedString = NSMutableAttributedString(string: "Hello Playground")
attributedString.setAttributes([.textStyle: TextStyle.headline], range: NSRange(location: 0, length: 5))
attributedString.enumerateAttributes(in: NSRange(location: 0, length: attributedString.length), options: []) { attributes, range, stop in
print(attributes, range, stop )
print(attributedString.attributedSubstring(from: range))
}
I have a NSAttributedString that was loaded from a RTF file, so it already holds several font-attributes for different ranges.
Now I want to adapt the font size to the screensize of the device, but when I add a whole new font attribute with a new size, the other fonts disappear.
Is there a way to change only the font size for the whole string?
If you only want to change the size of any given font found in the attributed string then you can do:
let newStr = someAttributedString.mutableCopy() as! NSMutableAttributedString
newStr.beginEditing()
newStr.enumerateAttribute(.font, in: NSRange(location: 0, length: newStr.string.utf16.count)) { (value, range, stop) in
if let oldFont = value as? UIFont {
let newFont = oldFont.withSize(20) // whatever size you need
newStr.addAttribute(.font, value: newFont, range: range)
}
}
newStr.endEditing()
print(newStr)
This will keep all other attributes in place.
If you want to replace all fonts in a given attributed string with a single font of a given size but keep all other attributes such as bold and italic, see:
NSAttributedString, change the font overall BUT keep all other attributes?
Okay I'm having an issue with NSAttributeString. I'm getting different html/css strings that occupy "busDescriptio" depending on what business you choose from a website database. I'm able to customize the string as I see fit as NSAttributeString but unfortunately on some cases the string already has css scripting in it which overrides my style that I insert into the string. Is it possible to override the scripting that is within my string? If so, how would I be able to do this? ***If I cant override the script can I just extract a certain tag from my string or replace it? Oh here is what my string looks like. As you see their is a style that is being poppulated within the string aka(busDescriptio). I'm not able to change that with regular scripting using NSAttributeString.
/* This is a random description my busDescriptio pulls in which changes everytime someone selects a different business*/<p><span style="color:rgb(0, 0, 0); font-family:verdana,arial,tahoma; font-size:12px">Baxter Eye Care has been serving The Woodlands with quality eye care and personal friendly service since 1981. Dr. Baxter, Dr. Daniels and Dr. Shosa are dedicated to your eye health and vision needs.</span></p>
This is the code I'm using to do this
extension String {
var html2String:String {
return NSAttributedString(data: dataUsingEncoding(NSUTF8StringEncoding)!, options: [NSDocumentTypeDocumentAttribute:NSHTMLTextDocumentType,NSCharacterEncodingDocumentAttribute:NSUTF8StringEncoding], documentAttributes: nil, error: nil)!.string
}
var html2NSAttributedString:NSAttributedString {
return NSAttributedString(data: dataUsingEncoding(NSUTF8StringEncoding)!, options: [NSDocumentTypeDocumentAttribute:NSHTMLTextDocumentType,NSCharacterEncodingDocumentAttribute:NSUTF8StringEncoding], documentAttributes: nil, error: nil)!
}
}
extension NSData{
var htmlString:String {
return NSAttributedString(data: self, options: [NSDocumentTypeDocumentAttribute:NSHTMLTextDocumentType,NSCharacterEncodingDocumentAttribute:NSUTF8StringEncoding], documentAttributes: nil, error: nil)!.string
}
}
let result = html2String("\(busDescriptio)") // Business Description HTML
let yourAttributedText = "<style type=\"text/css\">#busDescriptio{color:white;align-content:left;}#green{color:#0F0}#blue{color: #00F; font-weight: Bold; font-size: 32}</style><span id=\"busDescriptio\" >\(result),</span><span id=\"green\" > Green </span><span id=\"blue\">and Blue</span>".html2NSAttributedString
// Create UITextView
var textView = UITextView(frame: CGRectMake(0, 95.0, screenWidth-10, 300.0))
textView.attributedText = yourAttributedText
textView.backgroundColor = UIColor.clearColor()
textView.font = UIFont.preferredFontForTextStyle(UIFontTextStyleBody)
border.addSubview(textView)
func html2String(html:String) -> String {
return NSAttributedString(data: html.dataUsingEncoding(NSUTF8StringEncoding)!, options:[NSDocumentTypeDocumentAttribute:NSHTMLTextDocumentType,NSCharacterEncodingDocumentAttribute:NSUTF8StringEncoding], documentAttributes: nil, error: nil)!.string
}
I think you're stuck thinking about HTML. Once you have created an NSAttributedString or, more accurately, an NSMutableAttributedString from the HTML, you can just apply your own attributes. At that point, the HTML is no longer relevant. You certainly shouldn't try to achieve formatting by manipulating the HTML before converting it into an attributed string.
You don't say what "style" or attributes you want to change, so it's hard to give you an example, but just set or remove whatever attributes you want. You have the power to completely override whatever styling was introduced by the CSS in the HTML.
For example, do [someMutableAttributedString addAttribute:NSForegroundColorAttributeName value:[UIColor blueColor] range:NSMakeRange(0, someMutableAttributedString.length)] to change the color to blue.
Here's some Objective-C code which works for me on OS X:
NSString* html = #"<style type=\"text/css\">#busDescriptio{color:white;align-content:left;}#green{color:#0F0}#blue{color: #00F; font-weight: Bold; font-size: 32}</style><span id=\"busDescriptio\" ><p><span style=\"color:rgb(0, 0, 0); font-family:verdana,arial,tahoma; font-size:12px\">Baxter Eye Care has been serving The Woodlands with quality eye care and personal friendly service since 1981. Dr. Baxter, Dr. Daniels and Dr. Shosa are dedicated to your eye health and vision needs.</span></p>,</span><span id=\"green\" > Green </span><span id=\"blue\">and Blue</span>";
NSData* data = [html dataUsingEncoding:NSUTF8StringEncoding];
NSMutableAttributedString* str = [[NSMutableAttributedString alloc] initWithData:data
options:#{ NSCharacterEncodingDocumentOption: #(NSUTF8StringEncoding),
NSDocumentTypeDocumentOption: NSHTMLTextDocumentType }
documentAttributes:NULL
error:NULL];
[str addAttribute:NSForegroundColorAttributeName value:[NSColor redColor] range:NSMakeRange(0, str.length)];
self.label.attributedStringValue = str;
I don't work in Swift, but here's a pass at a simple translation:
let html = "<style type=\"text/css\">#busDescriptio{color:white;align-content:left;}#green{color:#0F0}#blue{color: #00F; font-weight: Bold; font-size: 32}</style><span id=\"busDescriptio\" ><p><span style=\"color:rgb(0, 0, 0); font-family:verdana,arial,tahoma; font-size:12px\">Baxter Eye Care has been serving The Woodlands with quality eye care and personal friendly service since 1981. Dr. Baxter, Dr. Daniels and Dr. Shosa are dedicated to your eye health and vision needs.</span></p>,</span><span id=\"green\" > Green </span><span id=\"blue\">and Blue</span>"
let data = html.dataUsingEncoding(NSUTF8StringEncoding)!
var str = NSMutableAttributedString(data:data,
options:[ NSCharacterEncodingDocumentOption: NSUTF8StringEncoding,
NSDocumentTypeDocumentOption: NSHTMLTextDocumentType ],
documentAttributes:nil,
error:nil)
str.addAttribute(NSForegroundColorAttributeName, value:NSColor.redColor(), range:NSMakeRange(0, str.length))
self.label.attributedStringValue = str;
So, the code starts with HTML code in a string. It creates an NSMutableAttributedString from that. Then it changes the foreground color, effectively replacing the color resulting from the HTML. Finally, it sets the attributed string as the content of an NSTextField label. For iOS, you could use a UILabel or UITextView or whatever.
In the code you put in your question, there are some things that are troublesome. It's not clear what busDescription is. Is it a string containing HTML code?
Is there a reason that you're interpolating it into a string to pass it to html2String()? That is, why this:
let result = html2String("\(busDescriptio)")
and not this:
let result = html2String(busDescriptio)
?
It seems that html2String() interprets HTML into an attributed string and then just extracts the plain text from that. Why are you doing that?
You are then interpolating that plain text into another block of HTML code. Again, why are you doing that? If you want to apply colors, fonts, etc. to the plain text string, just build an attributed string directly from that plain text string — no HTML involved — and apply the desired attributes.
Or, start from the original busDescriptio, make a mutable attributed string from that HTML code, and apply whatever attributes you like to that.
For example, here's another example:
NSString* busDescriptio = #"<p><span style=\"color:rgb(0, 0, 0); font-family:verdana,arial,tahoma; font-size:12px\">Baxter Eye Care has been serving The Woodlands with quality eye care and personal friendly service since 1981. Dr. Baxter, Dr. Daniels and Dr. Shosa are dedicated to your eye health and vision needs.</span></p>";
NSData* data = [busDescriptio dataUsingEncoding:NSUTF8StringEncoding];
NSMutableAttributedString* foo = [[NSMutableAttributedString alloc] initWithData:data
options:#{ NSCharacterEncodingDocumentOption: #(NSUTF8StringEncoding),
NSDocumentTypeDocumentOption: NSHTMLTextDocumentType }
documentAttributes:NULL
error:NULL];
[str addAttribute:NSFontAttributeName value:[NSFont fontWithName:#"Verdana" size:12] range:NSMakeRange(0, str.length)];
Basically, although your initial input is HTML code, you build a mutable attributed string from that and then don't work in HTML from that point on. Just apply and/or remove attributes from the attributed string, as desired. You can also build separate attributed strings, like your green or blue text in your example, and append those to the mutable one.
Okay so using what Ken Thomases wrote I was able to make it work! After looking at his code and seeing what I did wrong I was able to make it work. Here it is in Swift code just in case anyone has the same problem I had. I'm still having trouble with some images but ideally everything from font color, size, height, alignments and background work! Thanks
// busDescriptio is being occupied by a string with html and css scripting
var data: NSData = busDescriptio.dataUsingEncoding(NSUTF8StringEncoding)!
var foo: NSMutableAttributedString = NSMutableAttributedString(data: data,
options: [NSDocumentTypeDocumentAttribute:NSHTMLTextDocumentType,NSCharacterEncodingDocumentAttribute:NSUTF8StringEncoding],
documentAttributes:nil,
error:nil)!
var paragraph = NSMutableParagraphStyle()
paragraph.alignment = NSTextAlignment.Left
foo.addAttribute(NSFontAttributeName, value: UIFont(name: "Arial", size:12)!, range:NSMakeRange(0, foo.length))
foo.addAttribute(NSForegroundColorAttributeName, value: UIColor.whiteColor(), range: NSRange(location:0,length: foo.length))
foo.addAttribute(NSBackgroundColorAttributeName, value: UIColor.clearColor(), range: NSRange(location: 0, length: foo.length))
foo.addAttribute(NSParagraphStyleAttributeName, value:paragraph, range:NSMakeRange(0, foo.length))
I'm trying to apply two attributes to a string, one for kerning (NSKernAttributeName) and one for the font (NSFontAttributeName). Although I've checked and rechecked 1000 times, I can only get the kerning attribute to be applied to the string. Here's my setup:
let runAtTitle = "RUN AT"
var attRunAt = NSMutableAttributedString(string: runAtTitle)
let font = UIFont(name: "HelveticaNeue-Bold", size: 76.0)!
let attrs = [NSFontAttributeName: font, NSKernAttributeName: -3.0]
attRunAt.addAttributes(attrs, range: NSMakeRange(0, attRunAt.length))
runAtLabel.attributedText = attRunAt
When I build the app, the kerning is applied to my string, but the font is not. It uses the default 12pt Helvetica. Please tell me I'm doing something wrong.
I just tried your code in Playground and it works fine. Most likely you are setting the text attribute of the label after setting the attributedText. That will revert the string to the normal label string with its attributes, or perhaps for some strange reason keep the kern attribute.
Here is what I get with your code:
and after adding
label.text = "RUN AT"
I want to resize the font-size in some UITextViews. That works fine with an outlet collection and this code:
for (UITextView *view in self.viewsToResize) {
if ([view respondsToSelector:#selector(setFont:)]) {
[view setFont:[UIFont systemFontOfSize:view.font.pointSize + 5]];
}
}
But my problem is, that not every textView uses the systemFont in normal weight, some of them are in bold weight. Is it possible to get the font-weight? With a po view.font in the debug area I can see everything I need:
$11 = 0x0c596ea0 <UICFFont: 0xc596ea0> font-family: "Helvetica"; font-weight: normal; font-style: normal; font-size: 12px
But how can I access the font-weight?
Using a second outlet collection for the bold views could solve my problem. But I'm wondering that I found nothing to get only the font-weight.
I have figured out how to get the font weights, you have to spelunk down to Core Text:
let ctFont = font as CTFont
let traits = CTFontCopyTraits(ctFont)
let dict = traits as Dictionary
if let weightNumber = dict[kCTFontWeightTrait] as? NSNumber {
print(weightNumber.doubleValue)
}
Enjoy!
UIFont does not have a bold/italic/... property, so you will have to rely on the font name only.
This will be a problem if you don't know which fonts will be used.
In the case you know that you will use eg. only Helvetica you can try this:
UIFont *font = textview.font;
if([font.fontName isEqualToString:#"Helvetica-Bold"])
NSLog(#"It's Bold!");
Alternatively you can search font.fontName for the word "bold"/"medium"/"light" etc., but that's not a guarantee you will get something from every available font:
if ([font.fontName rangeOfString:#"bold" options:NSCaseInsensitiveSearch].location == NSNotFound) {
NSLog(#"font is not bold");
} else {
NSLog(#"font is bold!");
}
// if font.fontName contains "medium"....
// if font.fontName contains "italic"....
Check http://iosfonts.com/ for the available font names.
But my problem is, that not every textView uses the systemFont in
normal weight, some of them are in bold weight.
If you want to use Bold System Font then you can simply use
[UIFont boldSystemFontOfSize:15.0];
However, I am still thinking of that special case in which you need to use font-weight.
Update :
There is nothing in the UIFont Class using which you can get font-weight directly. You can take a look at UIFont Class Reference.
Only thing that you can do is to get the font-name and try to find out the "bold" sub-string in the font name. If any match found that means font-weight of that specific font is "bold".
But, still this is not the most efficient method.
You can get a UIFontDescriptor for a font using the fontDescriptor method. Then you get the fontAttributes dictionary of the UIFontDescriptor, get the UIFontDescriptorTraitsAttribute from the dictionary which returns another dictionary, then read the UIFontWeightTrait from that dictionary. Not tested.
Now it's tested: Doesn't work. fontAttributes always returns a dictionary with two keys for font name and font size, and that's it. I suppose "this doesn't work" is also an answer when something should work according to the documentation...
You can try symbolicTraits, but that's not useful either: It returns "bold" only if the whole font family is bold.