公司要做二维码扫描功能，研究了下，发现苹果有源生的类库，将代码贴一下，详细注释在代码中。
首先需要导入

<AVFoundation/AVFoundation.h>

定义了一些宏

/**
 *  屏幕 高 宽 边界
 */
#define SCREEN_HEIGHT [UIScreen mainScreen].bounds.size.height
#define SCREEN_WIDTH  [UIScreen mainScreen].bounds.size.width
#define SCREEN_BOUNDS  [UIScreen mainScreen].bounds

#define TOP (SCREEN_HEIGHT-220)/2
#define LEFT (SCREEN_WIDTH-220)/2

#define kScanRect CGRectMake(LEFT, TOP, 220, 220)

定义变量

{
    int num;
    BOOL upOrdown;
    NSTimer * timer;
    CAShapeLayer *cropLayer;
}
@property (strong,nonatomic)AVCaptureDevice * device;
@property (strong,nonatomic)AVCaptureDeviceInput * input;
@property (strong,nonatomic)AVCaptureMetadataOutput * output;
@property (strong,nonatomic)AVCaptureSession * session;
@property (strong,nonatomic)AVCaptureVideoPreviewLayer * preview;

@property (nonatomic, strong) UIImageView * line;

遵守代理AVCaptureMetadataOutputObjectsDelegate

详细代码如下，在这里就不累赘了，具体解释已经标注在代码里了。

- (void)viewDidLoad {
    [super viewDidLoad];
    // Do any additional setup after loading the view.
    self.view.backgroundColor = [UIColor blackColor];
    
    [self setCropRect:kScanRect];
    
    [self performSelector:@selector(setupCamera) withObject:nil afterDelay:0.3];
   
    [self configView];
    
}

-(void)configView{
    UIImageView * imageView = [[UIImageView alloc]initWithFrame:kScanRect];
    imageView.image = [UIImage imageNamed:@"pick_bg"];
    [self.view addSubview:imageView];
    
    upOrdown = NO;
    num =0;
    _line = [[UIImageView alloc] initWithFrame:CGRectMake(LEFT, TOP+10, 220, 2)];
    _line.image = [UIImage imageNamed:@"line.png"];
    [self.view addSubview:_line];
    
    timer = [NSTimer scheduledTimerWithTimeInterval:.02 target:self selector:@selector(animation1) userInfo:nil repeats:YES];
    
}
-(void)viewWillAppear:(BOOL)animated{
    //重新开启扫描
    if (_session != nil && timer != nil) {
        [_session startRunning];
        [timer setFireDate:[NSDate date]];
    }
    
}

-(void)animation1
{
    if (upOrdown == NO) {
        num ++;
        _line.frame = CGRectMake(LEFT, TOP+10+2*num, 220, 2);
        if (2*num == 200) {
            upOrdown = YES;
        }
    }
    else {
        num --;
        _line.frame = CGRectMake(LEFT, TOP+10+2*num, 220, 2);
        if (num == 0) {
            upOrdown = NO;
        }
    }
    
}


- (void)setCropRect:(CGRect)cropRect{
    cropLayer = [[CAShapeLayer alloc] init];
    CGMutablePathRef path = CGPathCreateMutable();
    CGPathAddRect(path, nil, cropRect);
    CGPathAddRect(path, nil, self.view.bounds);
    
    [cropLayer setFillRule:kCAFillRuleEvenOdd];
    [cropLayer setPath:path];
    [cropLayer setFillColor:[UIColor blackColor].CGColor];
    [cropLayer setOpacity:0.6];
    
    
    [cropLayer setNeedsDisplay];
    
    [self.view.layer addSublayer:cropLayer];
}

- (void)setupCamera
{
    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    if (device==nil) {
        UIAlertController *alert = [UIAlertController alertControllerWithTitle:@"提示" message:@"设备没有摄像头" preferredStyle:UIAlertControllerStyleAlert];
        [alert addAction:[UIAlertAction actionWithTitle:@"确认" style:UIAlertActionStyleDefault handler:^(UIAlertAction * _Nonnull action) {
            
        }]];
        [self presentViewController:alert animated:YES completion:nil];
        return;
    }
    // Device，获取摄像设备
    _device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    
    // Input，创建输入流
    _input = [AVCaptureDeviceInput deviceInputWithDevice:self.device error:nil];
    
    // Output，创建输出流
    _output = [[AVCaptureMetadataOutput alloc]init];
    [_output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
    
    //设置扫描区域
    CGFloat top = TOP/SCREEN_HEIGHT;
    CGFloat left = LEFT/SCREEN_WIDTH;
    CGFloat width = 220/SCREEN_WIDTH;
    CGFloat height = 220/SCREEN_HEIGHT;
    ///top 与 left 互换  width 与 height 互换
    [_output setRectOfInterest:CGRectMake(top,left, height, width)];
    
    
    // Session 初始化连接对象
    _session = [[AVCaptureSession alloc]init];
    // 高质量采集率
    [_session setSessionPreset:AVCaptureSessionPresetHigh];
    if ([_session canAddInput:self.input])
    {
        [_session addInput:self.input];
    }
    
    if ([_session canAddOutput:self.output])
    {
        [_session addOutput:self.output];
    }
    
    // 条码类型 设置条形码和二维码兼容
    [_output setMetadataObjectTypes:[NSArray arrayWithObjects:AVMetadataObjectTypeQRCode,AVMetadataObjectTypeEAN13Code, AVMetadataObjectTypeEAN8Code, AVMetadataObjectTypeCode128Code, nil]];
    
    // Preview 开始捕获
    _preview =[AVCaptureVideoPreviewLayer layerWithSession:_session];
    _preview.videoGravity = AVLayerVideoGravityResizeAspectFill;
    _preview.frame =self.view.layer.bounds;
    [self.view.layer insertSublayer:_preview atIndex:0];
    
    // Start
    [_session startRunning];
}

#pragma mark AVCaptureMetadataOutputObjectsDelegate
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
{
    NSString *stringValue;
    
    if ([metadataObjects count] >0)
    {
        //停止扫描
        [_session stopRunning];
        [timer setFireDate:[NSDate distantFuture]];
        
        AVMetadataMachineReadableCodeObject * metadataObject = [metadataObjects objectAtIndex:0];
        stringValue = metadataObject.stringValue;
        NSLog(@"扫描结果：%@",stringValue);
        [self.navigationController pushViewController:[JumpViewController new] animated:YES];
        
    } else {
        NSLog(@"无扫描信息");
        return;
    }
    
}

看下真机效果:

ds.gif

我在这里根据网上的朋友们写的东西，做了点总结并写了个demo，详细代码就是上面的了，如果需要demo的点击下载我上传github源码
当然了，如果你用swift语言在，你可以看下色长的简书关于swift下原生二维码扫描。@TomatosX