iOS 判断设备中是否有SIM卡

#一:项目中导入静态库: CoreTelephony.framework

#二:导入头文件

```

#import<CoreTelephony/CTTelephonyNetworkInfo.h>

#import<CoreTelephony/CTCarrier.h>

```

#三:实现验证方法

```

- (BOOL)isSIMInstalled{

            CTTelephonyNetworkInfo*networkInfo = [[CTTelephonyNetworkInfoalloc] init];

            CTCarrier*carrier = [networkInfo subscriberCellularProvider];

            if(!carrier.isoCountryCode) {

                NSLog(@"请安装好手机SIM卡后在拨打电话.");

                returnNO; 

             }else{

                    NSLog(@"存在SIM卡");returnYES;

             }

        }

```