你如何使用NSAttributedString？ [英] How do you use NSAttributedString?

问题描述

NSString 或 NSMutableStrings 中的多种颜色是不可能的。所以我听说过 NSAttributedString 随 iPad SDK 3.2 （或大约3.2）一起推出并可用iPhone上的 iPhone SDK 4.0测试版。

Multiple colours in an NSString or NSMutableStrings are not possible. So I've heard a little about the NSAttributedString which was introduced with the iPad SDK 3.2 (or around 3.2) and is available on the iPhone as of iPhone SDK 4.0 beta.

我想要一个有三种颜色的字符串。

I would like to have a string that has three colours.

我不使用3个单独的NSStrings的原因是因为三个 NSAttributedString 子串中每个子串的长度经常变化，所以我会更喜欢，不要使用任何计算来重新定位3个单独的 NSString 对象。

The reason I don't use 3 separate NSStrings, is because the length of each of the three NSAttributedString substrings changes often and so I would prefer, not to use any calculations to re-position 3 separate NSString objects.

如果可以使用 NSAttributedString 如何进行以下操作 - （如果不能使用NSAttributed字符串，你会怎么做）：

If it's possible using NSAttributedString how do I make the following - (if not possible with NSAttributed string how would you do it):

修改：
请记住， @first， @second 和 @third将随时被其他字符串替换。所以使用硬编码的NSRange值是行不通的。

Remember, @"first", @"second" and @"third" will be replaced by other strings at any time. So using hardcoded NSRange values won't work.

推荐答案

在构建属性字符串时，我更喜欢使用可变子类，只是为了保持清洁。

When building attributed strings, I prefer to use the mutable subclass, just to keep things cleaner.

话虽如此，这里是你如何创建一个三色属性字符串：

That being said, here's how you create a tri-color attributed string:

NSMutableAttributedString * string = [[NSMutableAttributedString alloc] initWithString:@"firstsecondthird"];
[string addAttribute:NSForegroundColorAttributeName value:[UIColor redColor] range:NSMakeRange(0,5)];
[string addAttribute:NSForegroundColorAttributeName value:[UIColor greenColor] range:NSMakeRange(5,6)];
[string addAttribute:NSForegroundColorAttributeName value:[UIColor blueColor] range:NSMakeRange(11,5)];

_{在浏览器中输入。 警告实现者}

显然你不会在这样的范围内进行硬编码。也许你可以这样做：

Obviously you're not going to hard-code in the ranges like this. Perhaps instead you could do something like:

NSDictionary * wordToColorMapping = ....;  //an NSDictionary of NSString => UIColor pairs
NSMutableAttributedString * string = [[NSMutableAttributedString alloc] initWithString:@""];
for (NSString * word in wordToColorMapping) {
  UIColor * color = [wordToColorMapping objectForKey:word];
  NSDictionary * attributes = [NSDictionary dictionaryWithObject:color forKey:NSForegroundColorAttributeName];
  NSAttributedString * subString = [[NSAttributedString alloc] initWithString:word attributes:attributes];
  [string appendAttributedString:subString];
  [subString release];
}

//display string

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