扫描二维码

#import "ViewController.h"
#import <AVFoundation/AVFoundation.h>

@interface ViewController () <AVCaptureMetadataOutputObjectsDelegate>

@property (nonatomic, weak) AVCaptureSession *session;
@property (nonatomic, weak) AVCaptureVideoPreviewLayer *layer;

@end

@implementation ViewController

- (void)viewDidLoad {
[super viewDidLoad];
}

- (void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event
{
// 1.创建捕捉会话
AVCaptureSession *session = [[AVCaptureSession alloc] init];
self.session = session;

// 2.添加输入设备(数据从摄像头输入)
AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:device error:nil];
[session addInput:input];

// 3.添加输出数据(示例对象-->类对象-->元类对象-->根元类对象)
AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];
[output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
[session addOutput:output];

// 3.1.设置输入元数据的类型(类型是二维码数据)
[output setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]];

// 4.添加扫描图层
AVCaptureVideoPreviewLayer *layer = [AVCaptureVideoPreviewLayer layerWithSession:session];
layer.frame = self.view.bounds;
[self.view.layer addSublayer:layer];
self.layer = layer;

// 5.开始扫描
[session startRunning];
}

#pragma mark - 实现output的回调方法
// 当扫描到数据时就会执行该方法
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
{
if (metadataObjects.count > 0) {
AVMetadataMachineReadableCodeObject *object = [metadataObjects lastObject];
NSLog(@"%@", object.stringValue);

// 停止扫描
[self.session stopRunning];

// 将预览图层移除
[self.layer removeFromSuperlayer];
} else {
NSLog(@"没有扫描到数据");
}
}

@end