检查网络状况

// 1.检测wifi状态
Reachability *wifi = [Reachability reachabilityForLocalWiFi];
// 2.检测手机是否能上网络(WIFI\3G\2.5G)
Reachability *conn = [Reachability reachabilityForInternetConnection];

// 3.判断网络状态
if ([wifi currentReachabilityStatus] != NotReachable) { // 有wifi
UIAlertView *al = [[UIAlertView alloc] initWithTitle:@”有wifi” message:@”” delegate:nil cancelButtonTitle:@”确定” otherButtonTitles:@”“, nil];
[al show];
} else if ([conn currentReachabilityStatus] != NotReachable) { // 没有使用wifi, 使用手机自带网络进行上网
UIAlertView *al = [[UIAlertView alloc] initWithTitle:@”使用手机自带网络进行上网” message:@”” delegate:nil cancelButtonTitle:@”确定” otherButtonTitles:@”“, nil];
[al show];
NSLog(@”使用手机自带网络进行上网”);

             } else { // 没有网络                 UIAlertView *al = [[UIAlertView alloc] initWithTitle:@"无网络" message:@"" delegate:nil cancelButtonTitle:@"确定" otherButtonTitles:@"", nil];                 [al show];        }