LAContext *context = [[LAContext alloc] init];  NSError *error = nil;  //驗證是否支持指紋識別  if ([context canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&error]) {    NSLog(@"支持指紋識別的應用");    //驗證身份    [context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:NSLocalizedString(@"需要指紋來驗證你的身份", @"hello") reply:^(BOOL success, NSError *error) {      if (success) {        NSLog(@"成功");      } else {        switch (error.code) {          case LAErrorUserCancel:            NSLog(@"用戶取消了授權 - %@", error.localizedDescription);            break;          case LAErrorUserFallback:            NSLog(@"用戶點擊了“輸入密碼”按鈕 - %@", error.localizedDescription);            break;          case LAErrorAuthenticationFailed:            NSLog(@"您已授權失敗3次 - %@", error.localizedDescription);            break;          case LAErrorTouchIDLockout:            NSLog(@"指紋被鎖定 - %@", error.localizedDescription);            break;          case LAErrorSystemCancel:            NSLog(@"應用程序進入后臺 - %@", error.localizedDescription);            break;          default:            NSLog(@"++%@--%zd", error.localizedDescription, error.code);            break;        }      }    }];  } else {    switch (error.code) {      case LAErrorPasscodeNotSet:        NSLog(@"未設置密碼 - %@", error.localizedDescription);        break;      case LAErrorTouchIDNotEnrolled:        NSLog(@"未注冊 Touch ID - %@", error.localizedDescription);        break;      case kLAErrorTouchIDNotAvailable:        NSLog(@"該設備不支持 Touch ID - %@", error.localizedDescription);        break;      default:        NSLog(@"--%@--%zd", error.localizedDescription, error.code);        break;    }  }