实用知识：指纹识别功能的实现

#import "ViewController.h"// iPhone5S开始, 6S第二代, 指纹识别验证 YES/NO// 授权验证, 指纹识别框架#import <LocalAuthentication/LocalAuthentication.h>@interface ViewController ()// 指纹识别@property (strong, nonatomic) LAContext *context;@end@implementation ViewController- (void)touchesBegan:(NSSet<UITouch *> *)touches withEvent:(UIEvent *)event{    // 弹出指纹验证    self.context = [[LAContext alloc] init];    // 判断硬件是否支持    /**     LAPolicyDeviceOwnerAuthenticationWithBiometrics NS_ENUM_AVAILABLE(NA, 8_0) = kLAPolicyDeviceOwnerAuthenticationWithBiometrics,  // 指纹识别, 5次失败上锁     LAPolicyDeviceOwnerAuthentication NS_ENUM_AVAILABLE(10_11, 9_0) = kLAPolicyDeviceOwnerAuthentication    // 指纹识别, 6次失败上锁     */    NSError *error;    // 判断设备是否可以使用指纹识别    BOOL isAuthentication = [self.context canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&error];    if (isAuthentication == NO || error) {        NSLog(@"不能使用: %@", error);        return;    }    /**     请求进行指纹识别     localizedReason: 告诉用户使用指纹识别的目的     */    NSString *reason = @"使用指纹进行用户登陆";    [self.context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:reason reply:^(BOOL success, NSError * _Nullable error) {        /**         // 指纹验证失败         LAErrorAuthenticationFailed = kLAErrorAuthenticationFailed,         // 用户取消, 点击了取消按钮         LAErrorUserCancel           = kLAErrorUserCancel,         // 用户取消, 点出了输入密码         LAErrorUserFallback         = kLAErrorUserFallback,         // 系统取消, (比如App进入后台)         LAErrorSystemCancel         = kLAErrorSystemCancel,         // 不能开始指纹验证, 设备没有设置密码         LAErrorPasscodeNotSet       = kLAErrorPasscodeNotSet,         // 不能开始指纹验证, Touch ID 不能用         LAErrorTouchIDNotAvailable  = kLAErrorTouchIDNotAvailable,         // 不能开始指纹验证, Touch ID 没有录入指纹         LAErrorTouchIDNotEnrolled   = kLAErrorTouchIDNotEnrolled,         // 指纹验证失败, 太多次的验证失败导致         // TouchID 锁住了, 需要输入密码         LAErrorTouchIDLockout   NS_ENUM_AVAILABLE(10_11, 9_0) = kLAErrorTouchIDLockout,         // App 取消了指纹验证         LAErrorAppCancel        NS_ENUM_AVAILABLE(10_11, 9_0) = kLAErrorAppCancel,         /// LAContext passed to this call has been previously invalidated.         LAErrorInvalidContext   NS_ENUM_AVAILABLE(10_11, 9_0) = kLAErrorInvalidContext         */        if (error) {            switch (error.code) {                case LAErrorAuthenticationFailed:                    NSLog(@"指纹验证失败");                    break;                case LAErrorUserCancel:                    NSLog(@"用户取消了指纹验证");                    break;                case LAErrorSystemCancel:                    NSLog(@"系统取消了指纹验证");                    break;                default:                    break;            }        }        // 结果回调        if (success) {            NSLog(@"验证成功");            // 执行相关的功能代码        }    }];}@end