扫描银行卡，获取银行卡号

实现功能：通过扫描银行卡，获取银行卡号。

在网上搜过后，选用了card.io这个SDK，其他的都要收费，不过这个sdk只能扫描有凸起的银行卡，平面字体无法识别。

过程如下：

（1）下载Card.io

Card.io是让手机摄像头获取信用卡的信息，中间利用了OCR（光学字符识别）的扫描技术返回结果，它还推出了SDK（软件开发包），让开发者们可以把card.io添加到自己的应用当中。可以在https://github.com/paypal/PayPal-iOS-SDK下载最新的SDK

（2）添加到项目里

1、将下载的SDK包里名为CardIO的文件拖到工程里，在TARGETS-Build Phases - Link Binary With Librarys添加下面依赖库
* Accelerate
* AVFoundation
* AudioToolbox
* CoreMedia
* MobileCoreServices

并且保证Build Settings里面这两项都是YES：
- Enable Modules (C and Objective-C)
- Link Frameworks Automatically

2、在TARGETS-Build Settings添加 -lc++到Other Linker Flags

（3）使用
我是把它作为一个viewController类使用

导入 #import “CardIO.h”

遵循协议CardIOPaymentViewControllerDelegate

- (void)viewWillAppear:(BOOL)animated {    [super viewWillAppear:animated];    [CardIOUtilities preload];}- (void)scanButtonAction{    CardIOPaymentViewController *scanViewController = [[CardIOPaymentViewController alloc] initWithPaymentDelegate:self];    scanViewController.modalPresentationStyle = UIModalPresentationFormSheet;    [self presentViewController:scanViewController animated:YES completion:nil];}

pragma mark - CardIOPaymentViewControllerDelegate

//扫描完成

- (void)userDidProvideCreditCardInfo:(CardIOCreditCardInfo *)info inPaymentViewController:(CardIOPaymentViewController *)paymentViewController {    NSLog(@"Scan succeeded with info: %@", info);// Do whatever needs to be done to deliver the purchased items.    [self dismissViewControllerAnimated:YEScompletion:nil];    self.infoLabel.text = info.cardNumber;    NSString *infoText = [NSStringstringWithFormat:@"Received card info. Number: %@, expiry: %02lu/%lu, cvv: %@.", info.redactedCardNumber, (unsignedlong)info.expiryMonth, (unsignedlong)info.expiryYear, info.cvv];    NSLog(@"%@", infoText);}

//用户取消扫描

- (void)userDidCancelPaymentViewController:(CardIOPaymentViewController *)paymentViewController {    NSLog(@"User cancelled scan");    [self dismissViewControllerAnimated:YEScompletion:nil];}