二维码扫描

   本文中我们介绍一下如何在iOS平台实现二维码扫描，我们可以借助一些优秀的第三方库，比如ZBar SDK和ZXing。在iOS7.0之后，我们也可以使用iOS系统原生扫描，通过AVFoundation框架来实现二维码扫描，不过AVFoundation框架不能识别相册中的二维码图片。

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1. 通过AVFoundation框架识别二维码

1.1 AVFoundation框架扫描二维码的基本方法

我们先来介绍一下如何使用AVFoundation框架实现二维码扫描。在iOS7之后，苹果自身提供了二维码的扫描功能，从效率上来说，原生的二维码远高于这些第三方框架。之前我们使用AVFoundation框架实现过拍照功能，基本的原理差不多类似；需要AVCaptureSession对象管理输入流和输出流；需要一个AVCaptureVideoPreviewLayer对象来显示信息。基本流程如下：

图中涉及到的几个相关类的说明如下：

• AVCaptureSession 管理输入（AVCaptureInput）和输出（AVCaptureOutput）流，包含开启和停止会话方法。
• AVCaptureDeviceInput 是AVCaptureInput的子类，可以作为输入捕获会话，用AVCaptureDevice实例初始化。
• AVCaptureDevice 代表了物理捕获设备如：摄像机。用于配置等底层硬件设置相机的自动对焦模式。
• AVCaptureMetadataOutput 是AVCaptureOutput的子类，处理输出捕获会话。捕获的对象传递给一个委托实现AVCaptureMetadataOutputObjectsDelegate协议。协议方法在指定的派发队列（dispatch queue）上执行。
• AVCaptureVideoPreviewLayerCALayer的一个子类，显示捕获到的相机输出流。

下面我们看一下具体的实现步骤：
示例代码：

#import "ViewController.h"#import <AVFoundation/AVFoundation.h>@interface ViewController ()<AVCaptureMetadataOutputObjectsDelegate>@property (weak, nonatomic) IBOutlet UISwitch *lightSwitch;// 闪光开关@property (nonatomic) AVCaptureSession *captureSession;//捕获的管理会话@property (nonatomic) AVCaptureVideoPreviewLayer *previewLayer;// 预览图层@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];}// 开始二维码扫描- (IBAction)startScan:(UIButton *)sender {    // 1. 初始化捕获会话，并添加输入对象    self.captureSession = [[AVCaptureSession alloc] init];    // 2. 初始化捕获设备对象AVCaptureDevice    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];    // 3. 初始化捕获设备的输入对象AVCaptureDeviceInput    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];    if (input == nil) {        NSLog(@"输入对象初始化失败");        return;    }    // 将输入对象添加到会话    [self.captureSession addInput:input];    // 4. 初始化输出对象AVCaptureMetadataOutput    AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];    // 将输出对象添加到会话    [self.captureSession addOutput:output];    // 设置输出对象源数据类型：AVMetadataObjectTypeQRCode条码类型    [output setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]];    // 设置输出对象代理，并实现代理方法    [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];    // 设置扫码区域为预览区域 默认全屏扫描    CGFloat w = self.view.frame.size.width;    CGFloat h = self.view.frame.size.height;    // rectOfInterest属性:区域大小是相对于设备的大小的，默认值是(0, 0, 1, 1)。但是区域的坐标系统X和Y是互换的，同时，宽高的比例也互换了。    [output setRectOfInterest:CGRectMake((h/2 -100)/h, (w/2 -100)/w, 200/h, 200/w)];    NSLog(@"%@",NSStringFromCGRect(output.rectOfInterest));    // 5. 初始化预览图层    self.previewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.captureSession];    self.previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;// 拉伸属性    self.previewLayer.frame = self.view.bounds;    [self.view.layer addSublayer:self.previewLayer];    // 6.开始会话    [self.captureSession startRunning];    // 关闭闪光灯    self.lightSwitch.on = NO;    [self.view bringSubviewToFront:self.lightSwitch];}#pragma mark -#pragma mark - AVCaptureMetadataOutputObjectsDelegate// 此方法是在识别到QRCode，并且完成转换。如果QRCode的内容越大，转换需要的时间就越长- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection {    if (metadataObjects != nil && [metadataObjects count] > 0) {        // 扫码成功 停止扫描，        [self.captureSession stopRunning];        // 获取扫码结果：        AVMetadataMachineReadableCodeObject *metadataObj = [metadataObjects objectAtIndex:0];        NSString *result;        if ([[metadataObj type] isEqualToString:AVMetadataObjectTypeQRCode]) {            result = metadataObj.stringValue;            NSLog(@"%@",result);        } else {            NSLog(@"不是二维码");        }    }}#pragma mark -#pragma mark - 开启闪光灯- (IBAction)lightOpenOrClose:(UISwitch *)sender {    BOOL isOpen = sender.on;    // 获取设备    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];    if ([device hasTorch]) {        [device lockForConfiguration:nil];        if (isOpen) {            [device setTorchMode:AVCaptureTorchModeOn];        } else {            [device setTorchMode:AVCaptureTorchModeOff];        }        [device unlockForConfiguration];    }}@end

1.2 AVFoundation框架扫描二维码的功能封装
上面是系统自带的二维码扫描的基本功能实现，下面我们来实现一下在实际开发中二维码扫描的实际效果，不过就是添加了一条扫描的线条。
示例代码：
Scan2CodeViewController.h

#import <UIKit/UIKit.h>@protocol ScanImageViewDelegate<NSObject>- (void)reportScanResult:(NSString *)result;@end@interface Scan2CodeViewController : UIViewController@property (nonatomic,weak)id <ScanImageViewDelegate>delegate;//代理方法传递数据@end示例代码：Scan2CodeViewController.m#import "Scan2CodeViewController.h"#import <AVFoundation/AVFoundation.h>#define SCANVIEW_EdgeTop 70.0#define SCANVIEW_EdgeLeft 50.0#define TINTCOLOR_ALPHA 0.2 //浅色透明度#define DARKCOLOR_ALPHA 0.3 //深色透明度#define VIEW_WIDTH [UIScreen mainScreen].bounds.size.width#define VIEW_HEIGHT [UIScreen mainScreen].bounds.size.heightstatic const char *kScanQRCodeQueueName = "ScanQRCodeQueue";@interface Scan2CodeViewController () <AVCaptureMetadataOutputObjectsDelegate>{    //设置扫描画面    UIView *_scanView;    NSTimer *_timer;    UIView *_QrCodeline;    UIView *_QrCodeline1;    UIImageView *_scanCropView;//扫描窗口    UIButton *_lightButton;//灯光按钮    AVCaptureSession *_captureSession;    AVCaptureVideoPreviewLayer *_videoPreviewLayer;}@end@implementation Scan2CodeViewController- (void)viewWillDisappear:(BOOL)animated{    [super viewWillDisappear:animated];    [self stopTimer];}- (void)viewDidLoad {    [super viewDidLoad];    //初始化扫描界面    [self setScanView];    // 开始扫描    [self startReading];    //启动定时器    [self createTimer];}- (BOOL)startReading{    // 获取 AVCaptureDevice 实例    NSError * error;    AVCaptureDevice *captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];    // 初始化输入流    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:captureDevice error:&error];    if (!input) {        NSLog(@"%@", [error localizedDescription]);        return NO;    }    // 创建会话    _captureSession = [[AVCaptureSession alloc] init];    //提高图片质量为1080P，提高识别效果    _captureSession.sessionPreset = AVCaptureSessionPreset1920x1080;    // 添加输入流    [_captureSession addInput:input];    // 初始化输出流    AVCaptureMetadataOutput *captureMetadataOutput = [[AVCaptureMetadataOutput alloc] init];    //设置扫描范围    captureMetadataOutput.rectOfInterest =CGRectMake((_scanCropView.frame.origin.y-10)/VIEW_HEIGHT, (_scanCropView.frame.origin.x-10)/VIEW_WIDTH, (_scanCropView.frame.size.width+10)/VIEW_HEIGHT, (_scanCropView.frame.size.height+10)/VIEW_WIDTH);    // 添加输出流    [_captureSession addOutput:captureMetadataOutput];    // 创建dispatch queue.    dispatch_queue_t dispatchQueue;    dispatchQueue = dispatch_queue_create(kScanQRCodeQueueName, NULL);    [captureMetadataOutput setMetadataObjectsDelegate:self queue:dispatchQueue];    // 设置元数据类型 AVMetadataObjectTypeQRCode    [captureMetadataOutput setMetadataObjectTypes:[NSArray arrayWithObject:AVMetadataObjectTypeQRCode]];    // 创建输出对象    _videoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:_captureSession];    [_videoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];    [_videoPreviewLayer setFrame:_scanView.layer.bounds];    [_scanView.layer insertSublayer:_videoPreviewLayer atIndex:0];    // 开始会话    [_captureSession startRunning];    return YES;}- (void)stopReading{    // 停止会话    [_captureSession stopRunning];    _captureSession = nil;}#pragma mark -#pragma mark - AVCaptureMetadataOutputObjectsDelegate-(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects      fromConnection:(AVCaptureConnection *)connection{    if (metadataObjects != nil && [metadataObjects count] > 0) {        AVMetadataMachineReadableCodeObject *metadataObj = [metadataObjects objectAtIndex:0];        NSString *result;        if ([[metadataObj type] isEqualToString:AVMetadataObjectTypeQRCode]) {            result = metadataObj.stringValue;        } else {            NSLog(@"不是二维码");        }        //调用代理对象的协议方法来实现数据传递        [self dismissViewControllerAnimated:YES completion:nil];        dispatch_async(dispatch_get_main_queue(), ^{            if ([self.delegate respondsToSelector:@selector(reportScanResult:)]) {                [self.delegate reportScanResult:result];            }        });        [self stopReading];    }    return;}- (void)createTimer{    _timer=[NSTimer scheduledTimerWithTimeInterval:2.2 target:self selector:@selector(moveUpAndDownLine) userInfo:nil repeats:YES];}- (void)stopTimer{    if ([_timer isValid] == YES) {        [_timer invalidate];        _timer = nil;    }}// 二维码的扫描区域- (void)setScanView{    _scanView=[[UIView alloc] initWithFrame:CGRectMake(0,0, VIEW_WIDTH,VIEW_HEIGHT )];    _scanView.backgroundColor=[UIColor clearColor];    [self.view addSubview:_scanView];    //最上部view    UIView *upView = [[UIView alloc] initWithFrame:CGRectMake(0,0, VIEW_WIDTH,SCANVIEW_EdgeTop)];    upView.alpha =TINTCOLOR_ALPHA;    upView.backgroundColor = [UIColor blackColor];    [_scanView addSubview:upView];    //左侧的view    UIView *leftView = [[UIView alloc] initWithFrame:CGRectMake(0, SCANVIEW_EdgeTop, SCANVIEW_EdgeLeft,VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft)];    leftView.alpha =TINTCOLOR_ALPHA;    leftView.backgroundColor = [UIColor blackColor];    [_scanView addSubview:leftView];    // 中间扫描区    _scanCropView=[[UIImageView alloc] initWithFrame:CGRectMake(SCANVIEW_EdgeLeft,SCANVIEW_EdgeTop, VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft, VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft)];    //scanCropView.image=[UIImage imageNamed:@""];    _scanCropView.layer.borderColor=[UIColor greenColor].CGColor;    _scanCropView.layer.borderWidth=2.0;    _scanCropView.backgroundColor=[UIColor clearColor];    [_scanView addSubview:_scanCropView];    //右侧的view    UIView *rightView = [[UIView alloc] initWithFrame:CGRectMake(VIEW_WIDTH - SCANVIEW_EdgeLeft,SCANVIEW_EdgeTop, SCANVIEW_EdgeLeft, VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft)];    rightView.alpha =TINTCOLOR_ALPHA;    rightView.backgroundColor = [UIColor blackColor];    [_scanView addSubview:rightView];    //底部view    UIView *downView = [[UIView alloc] initWithFrame:CGRectMake(0, VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft + SCANVIEW_EdgeTop, VIEW_WIDTH, VIEW_HEIGHT - (VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft + SCANVIEW_EdgeTop))];    //downView.alpha = TINTCOLOR_ALPHA;    downView.backgroundColor = [[UIColor blackColor] colorWithAlphaComponent:TINTCOLOR_ALPHA];    [_scanView addSubview:downView];    //用于说明的label    UILabel *labIntroudction= [[UILabel alloc] init];    labIntroudction.backgroundColor = [UIColor clearColor];    labIntroudction.frame=CGRectMake(0,5, VIEW_WIDTH,20);    labIntroudction.numberOfLines=1;    labIntroudction.font=[UIFont systemFontOfSize:15.0];    labIntroudction.textAlignment=NSTextAlignmentCenter;    labIntroudction.textColor=[UIColor whiteColor];    labIntroudction.text=@"将二维码对准方框，即可自动扫描";    [downView addSubview:labIntroudction];    //取消button    UIButton *cancelButton = [UIButton buttonWithType:UIButtonTypeCustom];    cancelButton.backgroundColor =[[UIColor blackColor] colorWithAlphaComponent:DARKCOLOR_ALPHA];    cancelButton.frame =CGRectMake(0, 90, VIEW_WIDTH, 40);    cancelButton.titleLabel.font =[UIFont systemFontOfSize:15.0];    cancelButton.titleLabel.textAlignment = NSTextAlignmentCenter;    [cancelButton setTitle:@"取消" forState:UIControlStateNormal];    [cancelButton addTarget:self action:@selector(cancelAction) forControlEvents:UIControlEventTouchUpInside];    [downView addSubview:cancelButton];    //用于开关灯操作的button    _lightButton = [UIButton buttonWithType:UIButtonTypeCustom];    _lightButton.frame =CGRectMake(0, 40, VIEW_WIDTH, 40);    [_lightButton setTitle:@"开启闪光灯" forState:UIControlStateNormal];    [_lightButton setTitleColor:[UIColor whiteColor] forState:UIControlStateNormal];    _lightButton.backgroundColor =[[UIColor blackColor] colorWithAlphaComponent:DARKCOLOR_ALPHA];    _lightButton.titleLabel.textAlignment=NSTextAlignmentCenter;    _lightButton.titleLabel.font=[UIFont systemFontOfSize:15.0];    [_lightButton addTarget:self action:@selector(openLight) forControlEvents:UIControlEventTouchUpInside];    [downView addSubview:_lightButton];    //画中间的基准线    _QrCodeline = [[UIView alloc] initWithFrame:CGRectMake(SCANVIEW_EdgeLeft, SCANVIEW_EdgeTop, VIEW_WIDTH- 2 * SCANVIEW_EdgeLeft, 2)];    _QrCodeline.backgroundColor = [UIColor greenColor];    [_scanView addSubview:_QrCodeline];    //画中间的基准线    _QrCodeline1 = [[UIView alloc] initWithFrame:CGRectMake(SCANVIEW_EdgeLeft, SCANVIEW_EdgeTop, VIEW_WIDTH- 2 * SCANVIEW_EdgeLeft, 2)];    _QrCodeline1.backgroundColor = [UIColor greenColor];    [_scanView addSubview:_QrCodeline1];    // 先让第二根线运动一次,避免定时器执行的时差,让用户感到启动App后,横线就开始移动    [UIView animateWithDuration:2.2 animations:^{        _QrCodeline1.frame = CGRectMake(SCANVIEW_EdgeLeft, VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft + SCANVIEW_EdgeTop - 2, VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft, 1);    }];}// 当地一根线到达底部时,第二根线开始下落运动,此时第一根线已经在顶部,当第一根线接着下落时,第二根线到达顶部.依次循环- (void)moveUpAndDownLine{    CGFloat Y = _QrCodeline.frame.origin.y;    if (Y == SCANVIEW_EdgeTop) {        [UIView animateWithDuration:2.2 animations:^{            _QrCodeline.frame = CGRectMake(SCANVIEW_EdgeLeft, VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft + SCANVIEW_EdgeTop - 2, VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft, 1);        }];        _QrCodeline1.frame = CGRectMake(SCANVIEW_EdgeLeft, SCANVIEW_EdgeTop, VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft, 1);    }    else if (Y == VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft + SCANVIEW_EdgeTop - 2) {        _QrCodeline.frame = CGRectMake(SCANVIEW_EdgeLeft, SCANVIEW_EdgeTop, VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft, 1);        [UIView animateWithDuration:2.2 animations:^{            _QrCodeline1.frame = CGRectMake(SCANVIEW_EdgeLeft, VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft + SCANVIEW_EdgeTop - 2, VIEW_WIDTH - 2 * SCANVIEW_EdgeLeft, 1);        }];    }}//照明灯光-(void)openLight{    if ([_lightButton.titleLabel.text isEqualToString:@"开启闪光灯"]) {        [self systemLightSwitch:YES];    } else {        [self systemLightSwitch:NO];    }}- (void)systemLightSwitch:(BOOL)open{    if (open) {        [_lightButton setTitle:@"关闭闪光灯" forState:UIControlStateNormal];    } else {        [_lightButton setTitle:@"开启闪光灯" forState:UIControlStateNormal];    }    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];    if ([device hasTorch]) {        [device lockForConfiguration:nil];        if (open) {            [device setTorchMode:AVCaptureTorchModeOn];        } else {            [device setTorchMode:AVCaptureTorchModeOff];        }        [device unlockForConfiguration];    }}// 取消button- (void)cancelAction{    [self dismissViewControllerAnimated:YES completion:nil];}@end

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2. 使用ZBarSDK识别二维码

   在iOS7.0以前，大部分应用识别二维码都是通过第三方库来实现的。事实上，在主流APP中二维码/条形码的作用主要分三种表现形式来集成：

• 调用手机摄像头并打开系统照相机全屏去拍摄。
• 自定义照相机视图的frame，自己控制并添加相关扫码指南。

• 识别相册图片中的二维码图片。

  首先我们先来看一下如何集成ZBarSDK：
  第一步：将 ZBarSDK导入到工程，并集成相关的框架，

• AVFoundation.framework
• CoreMedia.framework
• CoreVideo.framework
• QuartzCore.framework

• libiconv.dylib
  如下图：
  
  第二步：关闭代码优化
  导入相关框架后，系统编译仍然不通过，提示的错误如下：
  
  这是由于系统代码优化产生的错误，将Xcode的bitcode选项设置为No就可以通过编译了。
  

  第三步：导入头文件，初始化ZBar相机控制器，并实现相关代理；

• 调用系统相机全屏拍摄，使用ZBarReaderViewController，并声明协议。
• 自定义扫描窗口，使用ZBarReaderView，并声明协议。
• 识别相册的二维码图片，使用ZBarReaderController，并声明

2.1 调用系统相机：

示例代码：

#import "ViewController.h"#import "ZBarSDK.h"@interface ViewController ()<ZBarReaderDelegate>@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];}- (IBAction)systemCamara:(id)sender {    // 初始化扫码视图控制器    ZBarReaderViewController *reader = [ZBarReaderViewController new];    // 设置代理    reader.readerDelegate = self;    // 设置识别类型    ZBarImageScanner *scanner = reader.scanner;    [scanner setSymbology:ZBAR_I25                   config:ZBAR_CFG_ENABLE                       to:0];    reader.showsZBarControls = YES;    // 推出扫码视图控制器    [self presentViewController:reader animated:YES completion:nil];}- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info {    id results = [info objectForKey:ZBarReaderControllerResults];    ZBarSymbol * symbol;    for(symbol in results) {        NSString *result = symbol.data;        NSLog(@"%@",result);    }    // 退出拍照界面    [picker dismissViewControllerAnimated:YES completion:nil];}@end

注释：
直接调用系统相机来实现二维码扫描虽然简单，但是存在极大的问题，那就是这样只能做全屏扫描，不能自定义二维码扫描的选取框。

2.2 自定义扫描窗口

项目中实现的二维码扫描功能我们发现都是可以设置扫描范围内的，下面我们来看一下如何自定义扫描的窗口。

示例代码：

#import "ViewController.h"#import "ZBarSDK.h"@interface ViewController ()<ZBarReaderViewDelegate>@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];}#pragma mark -#pragma mark - 自定义扫描窗口- (IBAction)scan2Code:(id)sender {    // 初始化扫描窗口    ZBarReaderView *readerView = [[ZBarReaderView alloc] init];    // 自定义大小    readerView.frame = CGRectMake(self.view.frame.size.width/2-100, self.view.frame.size.height/2-100, 200, 200);    // 设置代理    readerView.readerDelegate = self;    // 添加到父视图    [self.view addSubview:readerView];    // 二维码识别设置    ZBarImageScanner *scanner = readerView.scanner;    [scanner setSymbology:ZBAR_I25                   config:ZBAR_CFG_ENABLE                       to:0];    // 开始扫描    [readerView start];}#pragma mark - ZBarReaderViewDelegate- (void)readerView:(ZBarReaderView *)readerView didReadSymbols:(ZBarSymbolSet *)symbols fromImage:(UIImage *)image {    // 获取扫描的标识    ZBarSymbol *symbol = nil;    for (symbol in symbols) {        NSString *result = symbol.data;        NSLog(@"%@",result);    }    // 停止扫描    [readerView stop];}@end

2.3 识别相册中的二维码图片：

使用ZBarSDK可以直接选中相册中的二维码图片进行识别，这是系统自带的识别功能所不具备的。下面是识别相册中的二维码图片的实现方法。

示例代码：

#import "ViewController.h"#import "ZBarSDK.h"@interface ViewController ()<UIImagePickerControllerDelegate,UINavigationControllerDelegate>@end@implementation ViewController- (void)viewDidLoad {    [super viewDidLoad];}// 识别相册图片中的二维码- (IBAction)pick2Code:(id)sender {    // 进入相册选中相册中的二维码图片    UIImagePickerController *imagePicker = [[UIImagePickerController alloc] init];    imagePicker.sourceType = UIImagePickerControllerSourceTypeSavedPhotosAlbum;// 图片来源为相册    imagePicker.delegate = self;    // 进入相册    [self presentViewController:imagePicker animated:YES completion:nil];}#pragma mark -#pragma mark - UIImagePickerControllerDelegate// 选中图片后调用该方法- (void)imagePickerController:(UIImagePickerController *)picker didFinishPickingMediaWithInfo:(NSDictionary<NSString *,id> *)info {    // 获取选中的图片    UIImage *image = [info objectForKey:UIImagePickerControllerOriginalImage];    CGImageRef cgImage = image.CGImage;    ZBarReaderController *reader = [[ZBarReaderController alloc] init];    reader.delegate = self;    ZBarSymbol *symbol = nil;    for (symbol in [reader scanImage:cgImage]) {        NSString *resulot = symbol.data;        NSLog(@"%@",resulot);    }    // 识别结束后返回主界面    [picker dismissViewControllerAnimated:YES completion:nil];}@end