由于最近的项目中用到了Touch ID，这里就给大家介绍下用法

1)首先你需要导入LocalAuthentication.framework，如下图所示

Touch_ID

2)在需要使用的文件导入#import <LocalAuthentication/LocalAuthentication.h>

3)因为TouchID只适用于iOS8及以上，所以我们首先需要判断系统是否为iOS8及以上SystemVersion [UIDevice currentDevice].systemVersion.doubleValue >= 8

然后判断机型是否支持TouchID，判断的方法为

- (BOOL)canEvaluatePolicy:(LAPolicy)policy error:(NSError *__autoreleasing *)error;

然后直接调用以下的方法直接调用TouchID

- (void)evaluatePolicy:(LAPolicy)policy localizedReason:(NSString *)localizedReason reply:(void(^)(BOOL success, NSError *error))reply;
 

[Demo示例][1]
[1]: https://github.com/lance017/TouchIDDemo

具体的代码在这

#import "ViewController.h"
#import <LocalAuthentication/LocalAuthentication.h>

#define SystemVersion [UIDevice currentDevice].systemVersion.doubleValue

@interface ViewController ()

@end

@implementation ViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    UIButton *button = [[UIButton alloc]init];
    button.center = self.view.center;
    button.bounds = CGRectMake(0, 0, 100, 40);
    [button setTitle:@"指纹识别" forState:UIControlStateNormal];
    [button setTitleColor:[UIColor blueColor] forState:UIControlStateNormal];
    [button addTarget:self action:@selector(click) forControlEvents:UIControlEventTouchUpInside];
    [self.view addSubview:button];
    // Do any additional setup after loading the view, typically from a nib.
}

- (void)click {
    //只有iOS8以上支持Touch ID
    if (SystemVersion >= 8.0) {
        LAContext *context = [[LAContext alloc]init];
        NSError *error = nil;
        //验证机器是否支持指纹识别
        if ([context canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&error]) {
            //支持指纹识别
            [context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:@"APP请求验证" reply:^(BOOL success, NSError * _Nullable error) {
                if (success) {
                    NSLog(@"验证成功");
                }
                
                switch (error.code) {
                    case LAErrorAppCancel:
                        NSLog(@"切换到其他APP，系统取消验证");
                        break;
                    case LAErrorUserCancel:
                        NSLog(@"用户取消验证");
                        break;
                    case LAErrorUserFallback:
                        NSLog(@"用户选择输入密码，切换主线程处理");
                        break;
                    default:
                        break;
                }
                
                if (error) {
                    NSLog(@"%@",error.localizedDescription);
                }
                
            }];
        }else{
            //机器不支持指纹识别
        }
    }else{
        //iOS8以下不支持Touch ID
    }
}
@end