将CFDictionaryRef转换为NSDictionary？

Question

我有代码（剥离）：

CFDictionaryRef *currentListingRef;
//declare currentListingRef here
NSDictionary *currentListing;
currentListing = (NSDictionary *) currentListingRef;

然后我收到错误：

  

强制转换非Objective-C指针类型'CFDictionaryRef *'（又名'const   ARC不允许使用struct __CFDictionary **'）到'NSDictionary *'

我做错了什么？如何从CFDictionaryRef转换为NSDictionary？

Answer 1

ARC改变了桥接的工作方式。

NSDictionary *original = [NSDictionary dictionaryWithObject:@"World" forKey:@"Hello"];
CFDictionaryRef dict = (__bridge CFDictionaryRef)original;
NSDictionary *andBack = (__bridge NSDictionary*)dict;
NSLog(@"%@", andBack);

Answer 2

在ARC中，应该这样做：

CFDictionaryRef currentListingRef = ...;
NSDictionary *currentListing = CFBridgingRelease(currentListingRef);

这将释放CF对象并将对象的所有权转移给ARC 否则你应该手动释放CF对象。

Answer 3

试试这段代码，

NSDictionary *ssidList = (__bridge NSDictionary*)myDict;
NSString *SSID = [ssidList valueForKey:@"SSID"];