33

我需要的只是遍历所有属性NSAttributedString并增加它们的字体大小。到目前为止，我已经成功循环并操作属性，但我无法保存回NSAttributedString. 我注释掉的那行对我不起作用。怎么挽回？

NSAttributedString *attrString = self.richTextEditor.attributedText;

[attrString enumerateAttributesInRange: NSMakeRange(0, attrString.string.length)
                               options:NSAttributedStringEnumerationReverse usingBlock:
 ^(NSDictionary *attributes, NSRange range, BOOL *stop) {

     NSMutableDictionary *mutableAttributes = [NSMutableDictionary dictionaryWithDictionary:attributes];        

     UIFont *font = [mutableAttributes objectForKey:NSFontAttributeName];
     UIFont *newFont = [UIFont fontWithName:font.fontName size:font.pointSize*2];         
     [mutableAttributes setObject:newFont forKey:NSFontAttributeName];
     //Error: [self.richTextEditor.attributedText setAttributes:mutableAttributes range:range];
     //no interfacce for setAttributes:range:

 }];
4

3 回答 3

57

Something like this should work:

NSMutableAttributedString *res = [self.richTextEditor.attributedText mutableCopy];

[res beginEditing];
__block BOOL found = NO;
[res enumerateAttribute:NSFontAttributeName inRange:NSMakeRange(0, res.length) options:0 usingBlock:^(id value, NSRange range, BOOL *stop) {
    if (value) {
        UIFont *oldFont = (UIFont *)value;
        UIFont *newFont = [oldFont fontWithSize:oldFont.pointSize * 2];
        [res removeAttribute:NSFontAttributeName range:range];
        [res addAttribute:NSFontAttributeName value:newFont range:range];
        found = YES;
    }
}];
if (!found) {
    // No font was found - do something else?
}
[res endEditing];
self.richTextEditor.attributedText = res;

At this point res has a new attributed string with all fonts being twice their original size.

于 2013-10-15T17:31:05.677 回答
5

NSMutableAttributedString在开始之前从您的原始属性字符串创建一个。在循环的每次迭代中，调用addAttribute:value:range:可变属性字符串（这将替换该范围内的旧属性）。

于 2013-10-15T17:06:29.523 回答
4

这是 maddy 答案的 Swift 端口（对我来说真的很好用！）。它包含在一个小扩展中。

import UIKit

extension NSAttributedString {
    func changeFontSize(factor: CGFloat) -> NSAttributedString {
        guard let output = self.mutableCopy() as? NSMutableAttributedString else {
            return self
        }

        output.beginEditing()
        output.enumerateAttribute(NSAttributedString.Key.font,
                                  in: NSRange(location: 0, length: self.length),
                                  options: []) { (value, range, stop) -> Void in
            guard let oldFont = value as? UIFont else {
                return
            }
            let newFont = oldFont.withSize(oldFont.pointSize * factor)
            output.removeAttribute(NSAttributedString.Key.font, range: range)
            output.addAttribute(NSAttributedString.Key.font, value: newFont, range: range)
        }
        output.endEditing()

        return output
    }
}
于 2019-02-04T21:29:53.797 回答