二维码扫描

Posted 2020-07-27 泛彼无垠

   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.height

static 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

---

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