ios - 用户拒绝使用时无法检查 Face ID

Question

如果设备支持Face ID 或Touch ID，我想对用户采取不同的操作。

当使用 Face ID 时，iOS 请求使用许可。 (与 Touch ID 不同)。

如果用户拒绝许可，context.biometryType 返回 LABiometryTypeNone。

有没有办法检查设备支持的Touch ID或Face ID。

LAContext *context = [[LAContext alloc] init];

NSError *error;

if ([context canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&error]) {

}

if (@available(iOS 11.0, *)) {
    if (context.biometryType == LABiometryTypeFaceID) {
        // support FaceID 
    }
}

// support TouchID

控制台输出

(lldb) po error
Error Domain=com.apple.LocalAuthentication Code=-6 "User has denied the use of biometry for this app." UserInfo={NSLocalizedDescription=User has denied the use of biometry for this app.}

(lldb) po context.biometryType
LABiometryTypeNone

NOTE: I Don't want to use passcode authentication. I just need to know device is support Touch ID or Face ID

Answer 1

使用 LAContext 的属性 biometryType 检查和评估可用的生物识别策略。 (对于密码身份验证，当生物识别失败时，使用:LAPolicyDeviceOwnerAuthentication)

试试看:

LAContext *laContext = [[LAContext alloc] init];

NSError *error;


// For a passcode authentication , when biometric fails, use: LAPolicyDeviceOwnerAuthentication
//if ([laContext canEvaluatePolicy: LAPolicyDeviceOwnerAuthentication error:&error]) {
if ([laContext canEvaluatePolicy: LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&error]) {    
    if (error != NULL) {
        // handle error
    } else {

        if (@available(iOS 11, *)) {
            if (laContext.biometryType == LABiometryTypeFaceID) {
                //localizedReason = "Unlock using Face ID"
                NSLog(@"FaceId support");
            } else if (laContext.biometryType == LABiometryTypeTouchID) {
                //localizedReason = "Unlock using Touch ID"
                NSLog(@"TouchId support");
            } else {
                //localizedReason = "Unlock using Application Passcode"
                NSLog(@"No biometric support or Denied biometric support");
            }
        } else {
            // Fallback on earlier versions
        }


        [laContext evaluatePolicy: LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:@"Test Reason" reply:^(BOOL success, NSError * _Nullable error) {

            if (error != NULL) {
                // handle error
            } else if (success) {
                // handle success response
            } else {
                // handle false response
            }
        }];
    }
}