iOS 下不用私有 API，有办法判断 2G 和 3G 网络么？

中国的iphone网络是区分2G和3G，要想获取当前的网络状态一直没有一个好的方法，网上给的例子也不尽让人满意
最近闲来无事，仔细的研究Apple提供的例子：Reachability
通过如下的代码：

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Reachability *reach = [Reachability reachabilityWithHostName:@"www.apple.com"];
NSLog(@"%d", [reach currentReachabilityStatus]);
return;

在currentReachabilityStatus函数中，我们注意到这样的输出：

static void PrintReachabilityFlags(SCNetworkReachabilityFlags flags, const char* comment)
{
#if kShouldPrintReachabilityFlags

NSLog(@"Reachability Flag Status: %c%c %c%c%c%c%c%c%c %s\n",
(flags & kSCNetworkReachabilityFlagsIsWWAN) ? 'W' : '-',
(flags & kSCNetworkReachabilityFlagsReachable) ? 'R' : '-',

(flags & kSCNetworkReachabilityFlagsTransientConnection) ? 't' : '-',
(flags & kSCNetworkReachabilityFlagsConnectionRequired) ? 'c' : '-',
(flags & kSCNetworkReachabilityFlagsConnectionOnTraffic) ? 'C' : '-',
(flags & kSCNetworkReachabilityFlagsInterventionRequired) ? 'i' : '-',
(flags & kSCNetworkReachabilityFlagsConnectionOnDemand) ? 'D' : '-',
(flags & kSCNetworkReachabilityFlagsIsLocalAddress) ? 'l' : '-',
(flags & kSCNetworkReachabilityFlagsIsDirect) ? 'd' : '-',
comment
);
#endif
}
当是wifi的时候输出R
当是3G的时候输出Rt
当是联通2G或者是移动的时候输出Rtc
在头文件定义如下：
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typedef enum {
NotReachable = 0,
ReachableViaWiFi,
ReachableVia3G,
ReachableVia2G,//当前无法区分是联通的2G还是移动的2G
} NetworkStatus;

因此我就是以这个为判断条件的，重写Reachability的函数：
- (NetworkStatus) networkStatusForFlags: (SCNetworkReachabilityFlags) flags
{
if ((flags & kSCNetworkReachabilityFlagsReachable) == 0)
{
return NotReachable;
}

BOOL retVal = NotReachable;

if ((flags & kSCNetworkReachabilityFlagsConnectionRequired) == 0)
{
// if target host is reachable and no connection is required
// then we'll assume (for now) that your on Wi-Fi
retVal = ReachableViaWiFi;
}

if ((((flags & kSCNetworkReachabilityFlagsConnectionOnDemand ) != 0) ||
(flags & kSCNetworkReachabilityFlagsConnectionOnTraffic) != 0))
{
// ... and the connection is on-demand (or on-traffic) if the
// calling application is using the CFSocketStream or higher APIs
if ((flags & kSCNetworkReachabilityFlagsInterventionRequired) == 0)
{
// ... and no [user] intervention is needed
retVal = ReachableViaWiFi;
}
}

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if ((flags & kSCNetworkReachabilityFlagsIsWWAN) == kSCNetworkReachabilityFlagsIsWWAN)
{
retVal = ReachableVia3G;
if((flags & kSCNetworkReachabilityFlagsReachable) == kSCNetworkReachabilityFlagsReachable) {
if((flags & kSCNetworkReachabilityFlagsTransientConnection) == kSCNetworkReachabilityFlagsTransientConnection) {
retVal = ReachableVia2G;
}
}
}

return retVal;
}

这样就可以正确的区分是2G，3G，wifi网络，这只支持中国地区，其他地区未考虑。
作者：Rush.D.Xzj

shellcodecow

2013-03-26 10:58:25 +08:00

好吧我复制黏贴了请自行补脑。Sorry