iPhone判断运营商

- (NSString *)getCarrier  
{  
    NSString *strCarrier = nil;  
    CTTelephonyNetworkInfo *networkInfo = [[CTTelephonyNetworkInfo alloc] init];  
    CTCarrier *carrier = [networkInfo subscriberCellularProvider];  
    if (carrier == nil)  
    {  
        [networkInfo release];  
        return strCarrier;  
    }  
      
    NSString *code = [carrier mobileNetworkCode];  
    if (code == nil)  
    {  
        [networkInfo release];  
        return strCarrier;  
    }  
      
    // 根据mobileNetworkCode判断运营商  
    if ([code isEqualToString:@"00"] || [code isEqualToString:@"02"] || [code isEqualToString:@"07"])  
        strCarrier = @"中国移动";  
    else if ([code isEqualToString:@"01"] || [code isEqualToString:@"06"])  
        strCarrier = @"中国联通";  
    else if ([code isEqualToString:@"03"] || [code isEqualToString:@"05"])  
        strCarrier = @"中国电信";  
    else if ([code isEqualToString:@"20"])  
        strCarrier = @"中国铁通";  
    else  
        strCarrier = nil;  
      
    [networkInfo release];  
      
    return strCarrier;  
}