#import <LocalAuthentication/LocalAuthentication.h>

LAContext *lacontext = [[LAContext alloc]init];
  // 判断设备是否支持指纹识别
  BOOL isSupport = [lacontext canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:NULL];
  if(!isSupport)
  {
    NSLog(@"不支持！");
    return;
  }
  [lacontext evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:@"请按下手印" reply:^(BOOL success, NSError *error) {
    if(success)
    {
      NSLog(@"成功后，处理接下来的逻辑");
    }
  }];

if ([UIDevice currentDevice].systemVersion.floatValue < 8.0) {
    NSLog(@"不支持");
    return;
  }

  LAContext *ctx = [[LAContext alloc] init];
  // 判断设备是否支持指纹识别
  if ([ctx canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:NULL]) {
    NSLog(@"支持");
    // 输入指纹，异步
    // 提示：指纹识别只是判断当前用户是否是手机的主人！程序原本的逻辑不会受到任何的干扰！
    [ctx evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:@"指纹登录" reply:^(BOOL success, NSError *error) {
      if (success) {
        // 登录成功
        // TODO
        NSLog(@"登陆成功");
      }
    }];
  } else {
    NSLog(@"不支持");
  }