iOS8使用TouchID

iOS8新增了LocalAuthentication框架，用於TouchID的授權使用。親測，目前需要用戶的設備支持指紋識別並已設置鎖屏，而且實際測試過程中反饋比較慢。不能直接跟第三方賬號密碼綁定，如果需要實現第三方應用直接指紋識別登錄，需要在本地存儲賬號信息，指紋識別通過之後再從本地讀取賬號信息登錄。總之，目前的指紋識別是跟設備、設備鎖屏密碼綁定的。測試代碼：

///使用TouchID
-(void)usingTouchID
{
    LAContext *myContext = [[[LAContext alloc] init] autorelease];
    NSError *authError = nil;
    NSString *myLocalizedReasonString = @"用於指紋登錄";
    if ([myContext canEvaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics error:&authError]) {
        [myContext evaluatePolicy:LAPolicyDeviceOwnerAuthenticationWithBiometrics
                  localizedReason:myLocalizedReasonString
                            reply:^(BOOL success, NSError *error) {
                                if (success) {
                                    // User authenticated successfully, take appropriate action
                                    NSLog(@"成功");
                                    UIAlertView *alertView = [[[UIAlertView alloc] initWithTitle:@"Suceess" message:@"已通過指紋識別！" delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK", nil] autorelease];
                                    [alertView show];
                                } else {
                                    // User did not authenticate successfully, look at error and take appropriate action
                                    NSLog(@"fail with error:%@",error);
                                    UIAlertView *alertView = [[[UIAlertView alloc] initWithTitle:@"Failed" message:[error localizedDescription] delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK", nil] autorelease];
                                    [alertView show];
                                }
                            }];
    } else {
        // Could not evaluate policy; look at authError and present an appropriate message to user
        NSLog(@"auth with error:%@",authError);
        UIAlertView *alertView = [[[UIAlertView alloc] initWithTitle:@"Failed" message:[authError localizedDescription] delegate:self cancelButtonTitle:nil otherButtonTitles:@"OK", nil] autorelease];
        [alertView show];
    }
}