ios 获取当前wifi名称

ios5之前可以通过读取配置文件获取，ios5以后苹果修改wifi列表文件位置，只有root权限才可以读取.

ios4:/System/Library/SystemConfiguration/WiFiManager.bundle/WiFiManager

ios5:/System/Library/SystemConfiguration/IPConfiguration.bundle/IPConfiguration

官方的API没有提供获取扫描所有wifi列表，相近功能的只有CaptiveNetwork，获取当前wifi的名称。

引用头文件<SystemConfiguration/CaptiveNetwork.h>

/*!
 @function CNCopySupportedInterfaces
 @discussion copies a list of all interfaces CaptiveNetworkSupport is monitoring.
 @result An array of CFStringRef- BSD interface names.
	 Returns NULL if an error was encountered.
	 You MUST release the returned value.
 */
CFArrayRef
CNCopySupportedInterfaces	(void)				__OSX_AVAILABLE_STARTING(__MAC_10_8,__IPHONE_4_1);

通过CNCopySupportedInterfaces获取wifi列表，实际测试中返回数组中只有一个值，即当前连接的wifi。

- (NSString *)currentWifiSSID 
{
    NSString *ssid = nil;
    NSArray *ifs = (__bridge   id)CNCopySupportedInterfaces();
    for (NSString *ifname in ifs) {
        NSDictionary *info = (__bridge id)CNCopyCurrentNetworkInfo((__bridge CFStringRef)ifname);
        if (info[@"SSIDD"])
         {
            ssid = info[@"SSID"];
        }
    }
    return ssid;
}