iOS应用内添加指纹识别

iOS8之后苹果发布了指纹识别的功能，通过touch ID来识别用户，做用户授权，主要是依赖于LocalAuthentication库

指纹识别：一判断设备是否支持指纹识别功能

二识别指纹，成功后做相应的动作，失败后提醒用户指纹识别失败

先引入#import <LocalAuthentication/LocalAuthentication.h>

LAContext *context = [[LAContext alloc] init];    NSError *error = nil;    //验证是否支持指纹识别    if ([context canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&error]) {        NSLog(@"支持指纹识别的应用");        //验证身份        [context evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics localizedReason:NSLocalizedString(@"需要指纹来验证你的身份", @"hello") reply:^(BOOL success, NSError *error) {            if (success) {                NSLog(@"成功");            } else {                switch (error.code) {                    case LAErrorUserCancel:                        NSLog(@"用户取消了授权 - %@", error.localizedDescription);                        break;                    case LAErrorUserFallback:                        NSLog(@"用户点击了“输入密码”按钮 - %@", error.localizedDescription);                        break;                    case LAErrorAuthenticationFailed:                        NSLog(@"您已授权失败3次 - %@", error.localizedDescription);                        break;                    case LAErrorTouchIDLockout:                        NSLog(@"指纹被锁定 - %@", error.localizedDescription);                        break;                    case LAErrorSystemCancel:                        NSLog(@"应用程序进入后台 - %@", error.localizedDescription);                        break;                    default:                        NSLog(@"%@---%zd", error.localizedDescription, error.code);                        break;                }            }        }];    } else {        switch (error.code) {            case LAErrorPasscodeNotSet:                NSLog(@"未设置密码 - %@", error.localizedDescription);                break;            case LAErrorTouchIDNotEnrolled:                NSLog(@"未注册 Touch ID - %@", error.localizedDescription);                break;            case kLAErrorTouchIDNotAvailable:                NSLog(@"该设备不支持 Touch ID - %@", error.localizedDescription);                break;            default:                NSLog(@"--%@--%zd", error.localizedDescription, error.code);                break;        }    }