iOS中应用内添加指纹识别的实例代码

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;
    }
  }