iOS touchID的使用(指纹识别代替密码)

#import 

//指纹识别的操作
-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event{
    
    //1. 判断系统版本
    if ([UIDevice currentDevice].systemVersion.floatValue >= 8.0) {
        
        //2. LAContext : 本地验证对象上下文
        LAContext *context = [LAContext new];
        
        //3. 判断是否可用
        //Evaluate: 评估  Policy: 策略,方针
        //LAPolicyDeviceOwnerAuthenticationWithBiometrics: 允许设备拥有者使用生物识别技术
        if (![context canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:nil]) {
            
            dispatch_async(dispatch_get_main_queue(), ^{
                
                UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"对不起, 指纹识别技术暂时不可用" message:nil delegate:nil cancelButtonTitle:@"确定" otherButtonTitles: nil];
                [alertView show];
            });
            
        }
        
        //4. 开始使用指纹识别
        //localizedReason: 指纹识别出现时的提示文字, 一般填写为什么使用指纹识别
        [context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:@"开启了指纹识别, 将打开隐藏功能" reply:^(BOOL success, NSError * _Nullable error) {
            
            if (success) {
                NSLog(@"指纹识别成功");
                // 指纹识别成功，回主线程更新UI,弹出提示框
                dispatch_async(dispatch_get_main_queue(), ^{
                    
                    UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"指纹识别成功" message:nil delegate:nil cancelButtonTitle:@"确定" otherButtonTitles: nil];
                    [alertView show];
                });
                
            }
            
            if (error) {
                
                // 错误的判断chuli
                
                if (error.code == -2) {
                    
                    // 取消操作，回主线程更新UI,弹出提示框
                    dispatch_async(dispatch_get_main_queue(), ^{
                        
                        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"用户取消了操作" message:nil delegate:nil cancelButtonTitle:@"确定" otherButtonTitles: nil];
                        [alertView show];
                        
                    });
                    
                } else {
                    NSLog(@"错误: %@",error);
                    // 指纹识别出现错误，回主线程更新UI,弹出提示框
                    dispatch_async(dispatch_get_main_queue(), ^{
                        
                        UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:nil message:@"指纹验证失败" delegate:nil cancelButtonTitle:@"确定" otherButtonTitles: nil];
                        [alertView show];
                        
                    });
                    
                }
                
            }
            
        }];
    } else {
        
        dispatch_async(dispatch_get_main_queue(), ^{
            
            UIAlertView *alertView = [[UIAlertView alloc] initWithTitle:@"对不起, 该手机不支持指纹识别" message:nil delegate:nil cancelButtonTitle:@"确定" otherButtonTitles: nil];
            [alertView show];
        });
        
    }
}