如何正确使用Apples Reachability类来判断互联网是否有效？

Question

可能重复:
Apples Reachability类有更复杂的替代方案吗？

这是一个例子:

Reachability *reachability = [Reachability reachabilityForInternetConnection];    
NetworkStatus internetStatus = [reachability currentReachabilityStatus];
if (internetStatus != NotReachable) {
    // Internet is reachable. Start download in background.
} else {
    // Create UIAlertView and tell user there is no functional internet!
}

问题:我听说在某些情况下WiFi" 可能需要VPN on Demand连接 ".那么我该如何正确地通知用户有关无功能的互联网连接？我假设上面的代码不足以解决这个问题.

Answer 1

这是我通常做的,虽然我没有在VPN上尝试过!我创建了一个独立的类来检查连接,比如它被命名WifiCheckClass.

在类的.h文件中:

#import <Foundation/Foundation.h>
#import "SystemConfiguration/SCNetworkReachability.h"

@interface UIDevice (DeviceConnectivity)
+(BOOL) cellularConnected;
+(BOOL) wiFiConnected;
+(BOOL) networkConnected;
@end

在.m文件中:

#import "WiFiCheckClass.h"

@implementation UIDevice (DeviceConnectivity)

+(BOOL) cellularConnected
{
    SCNetworkReachabilityFlags  flags = 0;
    SCNetworkReachabilityRef netReachability;
    netReachability = SCNetworkReachabilityCreateWithName(CFAllocatorGetDefault(), [@"www.google.com" UTF8String]);
    if(netReachability)
    {
        SCNetworkReachabilityGetFlags(netReachability, &flags);
        CFRelease(netReachability);
    }
    if(flags & kSCNetworkReachabilityFlagsIsWWAN) return YES;
    return NO;
}

+(BOOL) networkConnected
{
    SCNetworkReachabilityFlags flags = 0;
    SCNetworkReachabilityRef netReachability;
    BOOL  retrievedFlags = NO;
    netReachability = SCNetworkReachabilityCreateWithName(CFAllocatorGetDefault(), [@"www.google.com" UTF8String]);
    if(netReachability)
    {
        retrievedFlags  = SCNetworkReachabilityGetFlags(netReachability, &flags);
        CFRelease(netReachability);
    }
    if (!retrievedFlags || !flags) return NO;
    return YES;
}

+(BOOL) wiFiConnected
{
    if ([self cellularConnected]) return NO;
    return [self networkConnected];
}

@end

现在使用它非常简单:

if( [UIDevice wiFiConnected] || [UIDevice networkConnected] || [UIDevice cellularConnected] )
{
    //do what you want
}