iOS 原生态扫描二维码、条形码的功能。

1.导入AVFoundatin.framework。

2.新建一个viewController，命名为QRScanViewController，用于扫描的界面。

h文件如下，设置代理。

#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>

@protocol QRScanDelegate <NSObject>

-(void)ReadScan:(NSString *)codetext;

@end


@interface QRScanViewController : UIViewController //<AVCaptureMetadataOutputObjectsDelegate>
{
    id<QRScanDelegate> delegate;
}

@property (nonatomic,retain) id <QRScanDelegate> delegate;

@property (strong,nonatomic) UIView *boxView;

@property (strong,nonatomic) CALayer *scanLayer;

-(BOOL) startReading;

-(void) stopReading;

@property (nonatomic,strong) AVCaptureSession *captureSession;

@property (nonatomic,strong) AVCaptureVideoPreviewLayer *videoPreviewLayer;

@property (strong, nonatomic) UIView *viewPreview;

@end

m文件内容如下

#import "QRScanViewController.h"

@interface QRScanViewController ()

@end

@implementation QRScanViewController

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.captureSession = nil;
    // 设置扫描界面
    self.viewPreview = [[UIView alloc] initWithFrame:CGRectMake(self.view.frame.origin.x,self.view.frame.origin.y,self.view.frame.size.width,self.view.frame.size.height)];
    
    [self.view addSubview:self.viewPreview];
    
    //开始扫描
    [self startReading];
    
}

- (void)didReceiveMemoryWarning {
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}


-(BOOL) startReading
{
        NSError *error;
        //1.初始化捕捉设备（AVCaptureDevice），类型为AVMediaTypeVideo
        AVCaptureDevice *captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
        //2.用captureDevice创建输入流
        AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:captureDevice error:&error];
        if (!input) {
            NSLog(@"%@", [error localizedDescription]);
            return NO;
        }
        //3.创建媒体数据输出流
        AVCaptureMetadataOutput *captureMetadataOutput = [[AVCaptureMetadataOutput alloc] init];
        //4.实例化捕捉会话
        _captureSession = [[AVCaptureSession alloc] init];
        //4.1.将输入流添加到会话
        [_captureSession addInput:input];
        //4.2.将媒体输出流添加到会话中
        [_captureSession addOutput:captureMetadataOutput];
        //5.创建串行队列，并加媒体输出流添加到队列当中
        dispatch_queue_t dispatchQueue;
        dispatchQueue = dispatch_queue_create("myQueue", NULL);
        //5.1.设置代理
        [captureMetadataOutput setMetadataObjectsDelegate:self queue:dispatchQueue];
        //5.2.设置输出媒体数据类型，此处设置了多个条形码及二维码的类型
        [captureMetadataOutput setMetadataObjectTypes:@[AVMetadataObjectTypeEAN13Code,AVMetadataObjectTypeEAN8Code,AVMetadataObjectTypeCode128Code,AVMetadataObjectTypeCode39Code,AVMetadataObjectTypeQRCode]];
        //6.实例化预览图层
        _videoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:_captureSession];
        //7.设置预览图层填充方式
        [_videoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
        //8.设置图层的frame
        [_videoPreviewLayer setFrame:_viewPreview.layer.bounds];
        //9.将图层添加到预览view的图层上
        [_viewPreview.layer addSublayer:_videoPreviewLayer];
        //10.设置扫描范围
        captureMetadataOutput.rectOfInterest = CGRectMake(0.2f, 0.2f, 0.8f, 0.8f);
        //10.1.扫描框
        _boxView = [[UIView alloc] initWithFrame:CGRectMake(_viewPreview.bounds.size.width * 0.2f, _viewPreview.bounds.size.height * 0.2f, _viewPreview.bounds.size.width - _viewPreview.bounds.size.width * 0.4f, _viewPreview.bounds.size.height - _viewPreview.bounds.size.height * 0.4f)];
        _boxView.layer.borderColor = [UIColor greenColor].CGColor;
        _boxView.layer.borderWidth = 1.0f;
        [_viewPreview addSubview:_boxView];//10.开始扫描
        [_captureSession startRunning];
        return YES;
}

#pragma mark - AVCaptureMetadataOutputObjectsDelegate
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
{
        //判断是否有数据
        if (metadataObjects != nil && [metadataObjects count] > 0) {
            AVMetadataMachineReadableCodeObject *metadataObj = [metadataObjects objectAtIndex:0];
            //判断回传的数据类型
            if ([[metadataObj type] isEqualToString:AVMetadataObjectTypeQRCode]||
                [[metadataObj type] isEqualToString:AVMetadataObjectTypeEAN13Code]||
                [[metadataObj type] isEqualToString:AVMetadataObjectTypeEAN8Code]||
                [[metadataObj type] isEqualToString:AVMetadataObjectTypeCode128Code]||
                [[metadataObj type] isEqualToString:AVMetadataObjectTypeCode39Code]
                ) {
                NSString *code = [metadataObj stringValue];
                [self performSelectorOnMainThread:@selector(stopReading) withObject:nil waitUntilDone:NO];
                NSLog(@"send:%@",code);
                //此地方是为了保证ui运行在主线程中。
                dispatch_async(dispatch_get_main_queue(), ^{
                    [self.delegate ReadScan:code];
                    [self dismissViewControllerAnimated:YES completion:nil];
                });
                
            }
            
        }
}

-(void) stopReading
{
        [self.captureSession stopRunning];
        self.captureSession = nil;
        //[self.scanLayer removeFromSuperlayer];
        [self.videoPreviewLayer removeFromSuperlayer];
}

3.新建主界面，添加按钮和标签

使用代理

@interface ViewController : UIViewController <QRScanDelegate>

启动扫描

QRScanViewController *scan = [[QRScanViewController alloc] init];
    scan.delegate = self;
    [self presentModalViewController:scan animated:NO];

实现代理方法

-(void)ReadScan:(NSString *)codetext
{
    self.txtTxm.text = codetext;
    NSLog(@"recvcode:%@",codetext);
}

总结：

     第一是要注意条形码的类型。

     第二是保证让ui运行在主线程中，不然会有延时。