扫描二维码

• 导入媒体类

#import <AVFoundation/AVFoundation.h>

• 然后在 viewDidLoad 中 判断权限

- (void)viewDidLoad {
    [super viewDidLoad];
    // 判断权限
    [AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted) {
        dispatch_async(dispatch_get_main_queue(), ^{
            if (!granted) {
                NSLog(@"请在iPhone的”设置-隐私-相机“选项中，允许App访问你的相机");
                return ;
            }
            [self initQRCode];
        });
    }];
}

• 初始化扫描二维码

-(void)initQRCode
{
    //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:NULL];
    //3.创建媒体数据输出流
    AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];
    //4.实例化捕捉会话
    self.captureSession = [[AVCaptureSession alloc] init];
    [self.captureSession addInput:input]; // 将输入流添加到会话
    [self.captureSession addOutput:output]; // 将媒体输出流添加到会话中
    //5.设置代理 在主线程里刷新
    [output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
    [output setMetadataObjectTypes:[NSArray arrayWithObject:AVMetadataObjectTypeQRCode]]; // 设置输出媒体数据类型为QRCode
    // 6.实例化预览图层
    self.videoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:self.captureSession];
    [self.videoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill]; // 设置预览图层填充方式
    [self.videoPreviewLayer setFrame:self.view.bounds];
    // 7. 将图层添加到预览view的图层上
    [self.view.layer addSublayer:self.videoPreviewLayer];
    // 8. 设置扫描范围
    output.rectOfInterest = CGRectMake(0.2f, 0.2f, 0.8f, 0.8f);
    
    self.view.backgroundColor = [[UIColor blackColor] colorWithAlphaComponent:0.5];
    
    self.boxView = [[UIImageView alloc] initWithFrame:CGRectMake(self.view.frame.size.width * 0.2f, self.view.frame.size.height * 0.3f, self.view.frame.size.width - self.view.frame.size.width * 0.4f, self.view.frame.size.width - self.view.frame.size.width * 0.4f)];
    self.boxView.image = [UIImage imageNamed:@"scan_circle"];
    self.boxView.backgroundColor = [UIColor clearColor];
    [self.view addSubview:self.boxView];
    
    // 扫描线
    self.scanLine = [[UIImageView alloc] initWithFrame:CGRectMake(self.boxView.frame.size.width * 0.1, 4.0f, self.boxView.frame.size.width * 0.8, 3.0f)];
    self.scanLine.image = [UIImage imageNamed:@"scan_line"];
    [self.boxView addSubview:self.scanLine];
    
    [self startRunning]; // 开始扫描
}

• 开始扫描

#pragma mark - 开始扫描
-(void)startRunning
{
    if (self.captureSession) {
        self.isReading = YES;
        [self.captureSession startRunning];
        [self moveUpAndDownLine];
    }
}

-(void)stopRunning
{
    [self.captureSession stopRunning];
    [self.scanLine removeFromSuperview];
    [self.videoPreviewLayer removeFromSuperlayer];
}

// 扫描线上下移动
-(void)moveUpAndDownLine
{
    [UIView animateWithDuration:3.0f animations:^{
        
        self.scanLine.frame = CGRectMake(self.boxView.frame.size.width * 0.1, self.boxView.frame.size.height - 8.0f, self.boxView.frame.size.width * 0.8, 3.0f);
        
    } completion:^(BOOL finished) {
        
        self.scanLine.frame =  CGRectMake(self.boxView.frame.size.width * 0.1f, 4.0f, self.boxView.frame.size.width * 0.8, 3.0f);
        [self moveUpAndDownLine];
        
    }];
}

• AVCaptureMetadataOutputObjectsDelegate 代理方法中获取扫描结果

- (void)captureOutput:(AVCaptureOutput *)output didOutputMetadataObjects:(NSArray<__kindof AVMetadataObject *> *)metadataObjects fromConnection:(AVCaptureConnection *)connection {
    //判断是否有数据
    if (!_isReading) {
        return;
    }
    if (metadataObjects.count > 0) {
        _isReading = NO;
        AVMetadataMachineReadableCodeObject *metadataObject = metadataObjects[0];
        NSString *result = metadataObject.stringValue;
        NSLog(@"result - %@",result);
    }
}

-(void)viewWillDisappear:(BOOL)animated
{
    [super viewWillDisappear:animated];
    [self stopRunning];
}

-(void)dealloc
{
    self.captureSession = nil;
}