通过NSAttributedString属性循环以增加字体SIze [英] Looping Through NSAttributedString Attributes to Increase Font SIze

问题描述

我需要的是循环遍历 NSAttributedString 的所有属性并增加它们的字体大小。到目前为止，我已经到了成功循环并操纵属性的地步，但我无法保存回 NSAttributedString 。我评论出的这条线不适合我。如何保存？

All I need is to loop through all attributes of NSAttributedString and increase their font size. So far I got to the point where I successfully loop through and manipulate attributes but I cannot save back to NSAttributedString. The line I commented out is not working for me. How to save back?

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:

 }];

推荐答案

这样的事情应该有效：

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;

此时 res 有一个新的归因字符串，所有字体都是原始大小的两倍。

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

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