iOS-如何快速使用`NSMutableString` [英] iOS - How to use `NSMutableString` in swift
问题描述
我已经看到了这个Objective-C代码,但是我正在努力迅速地做到这一点:
I have seen this Objective-C code but I'm struggling to do the same in swift:
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;
我试图通过遍历每个属性来更改NSMutableAttributedString
中的字体.我很高兴听到有一种更好的方法,但是如果有人可以帮助我翻译以上内容,我将不胜感激.
I'm trying to change the fonts in a NSMutableAttributedString
by iterating over each of the attributes. I'm more than happy to hear that there is a better way but if anyone can help me translate the above I'd be more than greatful.
推荐答案
这是一个基本的实现.对我来说,这似乎很简单,并且您没有提供尝试,所以我不确定您是否有类似的东西,是否有问题,或者您是Swift的新手.
Here's a basic implementation. It seemed pretty straightforward to me, and you didn't provide your attempt, so I'm not sure if you have something similar and there's a problem with it, or if you're just new to Swift.
区别在于此实现使用可选的强制转换(as?
),我已对此进行了演示.实际上,由于NSFontAttributeName
可以保证提供UIFont
,因此不必是可选的.
One difference is that this implementation uses optional casting (as?
), which I did to demonstrate the concept. In practice, this doesn't need to be optional since NSFontAttributeName
is guaranteed to provide a UIFont
.
var res : NSMutableAttributedString = NSMutableAttributedString(string: "test");
res.beginEditing()
var found = false
res.enumerateAttribute(NSFontAttributeName, inRange: NSMakeRange(0, res.length), options: NSAttributedStringEnumerationOptions(0)) { (value, range, stop) -> Void in
if let oldFont = value as? UIFont {
let newFont = oldFont.fontWithSize(oldFont.pointSize * 2)
res.removeAttribute(NSFontAttributeName, range: range)
res.addAttribute(NSFontAttributeName, value: newFont, range: range)
found = true
}
}
if found == false {
}
res.endEditing()
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