如何清除 NSMutableAttributedString 中的属性？

Question

How do you set all the attributes in an NSMutableAttributedString to nothing? Do you have to enumerate through them and remove them?

I don't want to create a new one. I am working on the textStorage in NSTextView . Setting a new string resets the cursor position in NSTextView and fires the delegate.

Answer 1

You can remove all of the attributes like this:

NSMutableAttributedString *originalMutableAttributedString = //your string…

NSRange originalRange = NSMakeRange(0, originalMutableAttributedString.length);
[originalMutableAttributedString setAttributes:@{} range:originalRange];

Note that this uses set Attributes (not add ). From the docs:

These new attributes replace any attributes previously associated with the characters in aRange .

If you need to do any of it conditionally, you could also enumerate the attributes and remove them one-by-one:

[originalMutableAttributedString enumerateAttributesInRange:originalRange
                                                    options:kNilOptions
                                                 usingBlock:^(NSDictionary *attrs, NSRange range, BOOL *stop) {
                                                        [attrs enumerateKeysAndObjectsUsingBlock:^(NSString *attribute, id obj, BOOL *stop) {
                                                            [originalMutableAttributedString removeAttribute:attribute range:range];
                                                        }];
                                                    }];

According to the docs this is allowed:

If this method is sent to an instance of NSMutableAttributedString , mutation (deletion, addition, or change) is allowed.

---

Swift 2

If string is a mutable attributed string:

string.setAttributes([:], range: NSRange(0..<string.length))

And if you want to enumerate for conditional removal:

string.enumerateAttributesInRange(NSRange(0..<string.length), options: []) { (attributes, range, _) -> Void in
    for (attribute, object) in attributes {
        string.removeAttribute(attribute, range: range)
    }
}

Answer 2

swift 4:

I needed to remove the attributes from a textview in a reusable cell, they were transferred from one cell to another if the other was using the text property, so the text instead being only a text it was with the attributes from the previous cell. Only this worked for me, inspired by the accepted answer above:

iOS

let attr = NSMutableAttributedString(attributedString: (cell.textView?.attributedText)!)
    let originalRange = NSMakeRange(0, attr.length)
    attr.setAttributes([:], range: originalRange)
    cell.textView?.attributedText = attr
    cell.textView?.attributedText = NSMutableAttributedString(string: "", attributes: [:])
    cell.textView?.text = ""

macOS

textView.textStorage?.setAttributedString(NSAttributedString(string: ""))

Answer 3

How I remove and add attributes of a string in a tableView cellForRowAt indexPath. Create a new NSMutableAttributedString because it is immutable

// strike through on text
    let attributeString =  NSMutableAttributedString(string: "your string")
    attributeString.addAttribute(NSAttributedString.Key.strikethroughStyle, value: 2, range: NSMakeRange(0, attributeString.length))

    let removedAttributeString = NSMutableAttributedString(string: "your string")
    removedAttributeString.removeAttribute(NSAttributedString.Key.strikethroughStyle, range: NSMakeRange(0, attributeString.length))

    if (item.done == true) {
        // applies strike through on text
        cell.textLabel?.attributedText = attributeString

    } else {
        // removes strike through on text
        cell.textLabel?.attributedText = removedAttributeString
    }

Answer 4

NSAttributedString is immutable therefore you can't do much with an instance of it. One option is to use the string property of NSAttributedString , create a new NSMutableAttributedString with it and apply the desired attributes or make a mutableCopy of your NSAttributedString instance and modify the current attributes for ranges.

Answer 5

First off, it would have to be an NSMutableAttributedString, as that has the method of removeAttribute(name: String, range: NSRange), and yes it looks like you would have to enumerate them and remove them.

Why not try this approach (Swift):

let s1 = <some NSAttributedString>
var s2 = NSMutableAttriutedString(string: s1.string())