blocks|key|1391349|text|它们是等效的，所以您可以直接转换CFStringRef：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1391350|NSString+*aNSString+=+(NSString*)aCFString;|code-block|syntax|javascript|1391351|有关更多信息，请参阅Toll-Free+Bridged+Types。|offset|length|1391352|entityMap|0|LINK|mutability|MUTABLE|url|https://developer.apple.com/library/ios/documentation/corefoundation/Conceptual/CFDesignConcepts/Articles/tollFreeBridgedTypes.html^0|0|0|A|N|0|0^^$0|@$1|2|3|4|5|6|7|S|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|T|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|U|8|@]|9|@$I|V|J|W|1|X]]|A|$]]|$1|K|3|-4|5|6|7|Y|8|@]|9|@]|A|$]]]|L|$M|$5|N|O|P|A|$Q|R]]]]

They are equivalent, so you can just cast the CFStringRef:

<pre><code>NSString *aNSString = (NSString*)aCFString;
</code></pre>

For more info, see <a href="https://developer.apple.com/library/ios/documentation/corefoundation/Conceptual/CFDesignConcepts/Articles/tollFreeBridgedTypes.html" rel="nofollow noreferrer">Toll-Free Bridged Types</a>.

blocks|key|1391450|text|NSString和CFStringRef是“免费桥接的”，这意味着你可以简单地在它们之间进行类型转换。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1391451|例如：|1391452|CFStringRef+aCFString+=+(CFStringRef)aNSString;|code-block|syntax|javascript|1391453|完美而透明地工作。同样：|1391454|NSString+*aNSString+=+(NSString+*)aCFString;|1391455|之前的语法用于MRC。如果您使用的是ARC，则新的强制转换语法如下：|1391456|NSString+*aNSString+=+(__bridge+NSString+*)aCFString;|1391457|效果也很好。需要注意的关键一点是，CoreFoundation通常会返回引用计数为%2B1的对象，这意味着它们需要被释放(所有CFTypeCreate格式函数都会这样做)。|1391458|好消息是，在Cocoa中，您可以安全地使用自动释放或释放来释放它们。|1391459|entityMap^0|0|0|0|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|X|8|@]|9|@]|A|$]]|$1|D|3|E|5|F|7|Y|8|@]|9|@]|A|$G|H]]|$1|I|3|J|5|6|7|Z|8|@]|9|@]|A|$]]|$1|K|3|L|5|F|7|10|8|@]|9|@]|A|$G|H]]|$1|M|3|N|5|6|7|11|8|@]|9|@]|A|$]]|$1|O|3|P|5|F|7|12|8|@]|9|@]|A|$G|H]]|$1|Q|3|R|5|6|7|13|8|@]|9|@]|A|$]]|$1|S|3|T|5|6|7|14|8|@]|9|@]|A|$]]|$1|U|3|-4|5|6|7|15|8|@]|9|@]|A|$]]]|V|$]]

NSString and CFStringRef are "Toll free bridged", meaning that you can simply typecast between them.

For example:

<pre><code>CFStringRef aCFString = (CFStringRef)aNSString;
</code></pre>

works perfectly and transparently. Likewise:

<pre><code>NSString *aNSString = (NSString *)aCFString;
</code></pre>

The previous syntax was for MRC. If you're using ARC, the new casting syntax is as follows:

<pre><code>NSString *aNSString = (__bridge NSString *)aCFString;
</code></pre>

works as well. The key thing to note is that CoreFoundation will often return objects with +1 reference counts, meaning that they need to be released (all CF[Type]Create format functions do this).

The nice thing is that in Cocoa you can safely use autorelease or release to free them up.

blocks|key|1606425|text|我要补充的是，您不仅可以通过类型转换从CFString转换到NSString，而且它也可以以另一种方式工作。您可以删除CFStringCreateWithCString消息，这将减少稍后需要发布的内容。(CF在Cocoa使用alloc的情况下使用Create，因此无论哪种方式，您都需要发布它。)|type|unstyled|depth|inlineStyleRanges|offset|length|style|CODE|entityRanges|data|1606426|生成的代码如下：|1606427|NSString+*escapedString;
NSString+*unescapedString+=+[(NSString+*)+CFXMLCreateStringByUnescapingEntities(NULL,+(CFStringRef)+escapedString,+NULL)+autorelease];|code-block|syntax|javascript|1606428|entityMap^0|1N|P|34|5|3F|6|0|0|0^^$0|@$1|2|3|4|5|6|7|O|8|@$9|P|A|Q|B|C]|$9|R|A|S|B|C]|$9|T|A|U|B|C]]|D|@]|E|$]]|$1|F|3|G|5|6|7|V|8|@]|D|@]|E|$]]|$1|H|3|I|5|J|7|W|8|@]|D|@]|E|$K|L]]|$1|M|3|-4|5|6|7|X|8|@]|D|@]|E|$]]]|N|$]]

I'll add that not only can you go from CFString to NSString with only a type-cast, but it works the other way as well. You can drop the <code>CFStringCreateWithCString</code> message, which is one fewer thing you need to release later. (CF uses <code>Create</code> where Cocoa uses <code>alloc</code>, so either way, you would have needed to release it.)

The resulting code:

<pre><code>NSString *escapedString;
NSString *unescapedString = [(NSString *) CFXMLCreateStringByUnescapingEntities(NULL, (CFStringRef) escapedString, NULL) autorelease];
</code></pre>

blocks|key|1606499|text|我对ARC和CFStrings的保留计数有点问题。使用NilObjects+answer，稍微调整一下，对我来说是完美的。我只是添加了保留的例如。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1606500|CFStringRef+cfstringRef+=+(__bridge_retained++CFStringRef)aNsString;|code-block|syntax|javascript|1606501|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

I was having an issue with ARC and the retain count of CFStrings. Using NilObjects answer with a slight tweak worked perfect for me. I just added retained eg. 

<pre><code>CFStringRef cfstringRef = (__bridge_retained CFStringRef)aNsString;
</code></pre>

blocks|key|1391671|text|你必须对它进行转换：|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1391672|CFStringRef+CFstringFileName=(__bridge+CFStringRef)NSstringFileName;|code-block|syntax|javascript|1391673|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

You have to cast it:

<pre><code>CFStringRef CFstringFileName=(__bridge CFStringRef)NSstringFileName;
</code></pre>

blocks|key|1391707|text|您可以使用:与CFStringRef数据中心；|type|unstyled|depth|inlineStyleRanges|entityRanges|data|1391708|NSString+*sId+=+[NSString+stringWithFormat:@"%25@",+(NSString*)idc];|code-block|syntax|javascript|1391709|entityMap^0|0|0^^$0|@$1|2|3|4|5|6|7|I|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|J|8|@]|9|@]|A|$E|F]]|$1|G|3|-4|5|6|7|K|8|@]|9|@]|A|$]]]|H|$]]

Youcan use :With CFStringRef idc;

<pre><code>NSString *sId = [NSString stringWithFormat:@"%@", (NSString*)idc];
</code></pre>

<pre><code>NSString *aNSString;
CFStringRef aCFString;
aCFString = CFStringCreateWithCString(NULL, [aNSString UTF8String], NSUTF8StringEncoding);
aCFString = CFXMLCreateStringByUnescapingEntities(NULL, aCFString, NULL);
</code></pre>

How can I get a new <code>NSString</code> from <code>aCFString</code>?

How to convert CFStringRef to NSString?

翻译质量差，导致语言生硬或混乱。

没有提供实际的解决方法或示例。

解答不清晰，无法理解或解决问题。

页面排版不美观，阅读体验差。

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NSString *aNSString;CFStringRef aCFString;aCFString = CFStringCreateWithCString(NULL, [aNSString UTF8String], NSUTF8StringEncoding);aCFString = CFXMLCreateStrin...

问如何将CFStringRef转换为NSString？
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问如何将CFStringRef转换为NSString？EN