for (id objects in metadataObjects) {// 判断检测到的对象类型if (![objects isKindOfClass:[AVMetadataMachineReadableCodeObject class]]) {return;}// 转换对象坐标
AVMetadataMachineReadableCodeObject *obj = (AVMetadataMachineReadableCodeObject *)[preViewLayer transformedMetadataObjectForMetadataObject:objects];// 判断扫描范围if (!CGRectContainsRect(self.boxView.frame, obj.bounds)) {continue;}}

@protocol ScanQrcodeVControllerDelegate <NSObject>
// 二维码返回结果
-(void)scanQrcodeWithNString:(NSString *) ruselt;
@end
@interface ScanQrcodeVController : UIViewController
@property (nonatomic, weak) id<ScanQrcodeVControllerDelegate>delegate;
@end

@interface ScanQrcodeVController ()<AVCaptureMetadataOutputObjectsDelegate>
// 会话
@property (nonatomic, strong) AVCaptureSession *session;
// 定时器
@property (nonatomic, strong) CADisplayLink *link;
// 扫描线
@property (nonatomic, strong) CALayer *scanLayer;
// 扫描框
@property (nonatomic, weak) UIView *boxView;
/// 保存二维码结果
@property (nonatomic, copy) NSString *string;
@end@implementation ScanQrcodeVController
- (void)viewDidLoad {[super viewDidLoad];self.navigationItem.leftBarButtonItem = [[UIBarButtonItem alloc] initWithImage:[UIImage imageNamed:@"NavBack"] style:UIBarButtonItemStylePlain target:self action:@selector(goBack)];self.navigationItem.rightBarButtonItem = [[UIBarButtonItem alloc] initWithTitle:@"确定" style:UIBarButtonItemStylePlain target:self action:@selector(doneClick)];[self scanCode];
}-(void)scanCode {CADisplayLink *link = [CADisplayLink displayLinkWithTarget:self selector:@selector(updataFrame)];self.link = link;link.frameInterval = 3;[link addToRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];

　　

// 判断相机是否授权使用相机

AVAuthorizationStatus status = [AVCaptureDevice authorizationStatusForMediaType:AVMediaTypeVideo];

if(status == AVAuthorizationStatusAuthorized) {

} else if(status == AVAuthorizationStatusDenied){

// NSLog(@"denied不允许");

return ;

} else if(status == AVAuthorizationStatusNotDetermined){

[AVCaptureDevice requestAccessForMediaType:AVMediaTypeVideo completionHandler:^(BOOL granted) {

if(granted){

//                NSLog(@"允许");

} else {

//                NSLog(@"不允许");

return;

}

}];

// 1.获取输入设备

    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];// 2.创建输入对象NSError *error;AVCaptureDeviceInput *inPut = [[AVCaptureDeviceInput alloc] initWithDevice:device error:&error];if (inPut == nil) {UIAlertView *aler = [[UIAlertView alloc] initWithTitle:@"提示" message:@"设备不可用" delegate:nil cancelButtonTitle:nil otherButtonTitles:@"确定", nil];[self.view addSubview:aler];[aler show];return;}// 3.创建输出对象AVCaptureMetadataOutput *outPut = [[AVCaptureMetadataOutput alloc] init];// 4.设置代理监听输出对象的输出流  说明：使用主线程队列，相应比较同步，使用其他队列，相应不同步，容易让用户产生不好的体验
    [outPut setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];// 5.创建会话AVCaptureSession *session = [[AVCaptureSession alloc] init];self.session = session;// 6.将输入和输出对象添加到会话if ([session canAddInput:inPut]) {[session addInput:inPut];}if ([session canAddOutput:outPut]) {[session addOutput:outPut];}// 7.告诉输出对象, 需要输出什么样的数据  // 提示：一定要先设置会话的输出为output之后，再指定输出的元数据类型！
    [outPut setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]];// 8.创建预览图层AVCaptureVideoPreviewLayer *preViewLayer = [AVCaptureVideoPreviewLayer layerWithSession:session];preViewLayer.frame = self.view.bounds;[self.view.layer insertSublayer:preViewLayer atIndex:0];// 9.设置扫面范围outPut.rectOfInterest = CGRectMake(0.2, 0.18, 0.6, 0.5);// 10.设置扫描框UIView *boxView = [[UIView alloc] initWithFrame:CGRectMake(0.2 * SrceenW, 0.18 * SrceenH, 0.6 * SrceenW, 0.5 * SrceenH)];self.boxView = boxView;boxView.layer.borderColor = [UIColor yellowColor].CGColor;boxView.layer.borderWidth = 3;[self.view addSubview:boxView];// 设置扫描线CALayer *scanLayer = [[CALayer alloc] init];self.scanLayer = scanLayer;scanLayer.frame = CGRectMake(0, 0, boxView.bounds.size.width, 2);scanLayer.backgroundColor = [UIColor redColor].CGColor;[boxView.layer addSublayer:scanLayer];// 开始扫描
    [session startRunning];
}-(void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection {    for (id objects in metadataObjects) {

// 判断检测到的对象类型

if (![objects isKindOfClass:[AVMetadataMachineReadableCodeObject class]]) {

return;

}

// 转换对象坐标

AVMetadataMachineReadableCodeObject *obj = (AVMetadataMachineReadableCodeObject *)[preViewLayer transformedMetadataObjectForMetadataObject:objects];

// 判断扫描范围

if (!CGRectContainsRect(self.boxView.frame, obj.bounds)) {

continue;

　　　　　}

// 设置代理

　　　　　 if ([self.delegate respondsToSelector:@selector(scanQrcodeWithNString:)]) {

[self.delegate scanQrcodeWithNString:obj.stringValue];

　　　　　}

　　　　　// 停止扫描

　　　　 [self.session stopRunning];

// 移除CADisplayLink对象

[self.link removeFromRunLoop:[NSRunLoop mainRunLoop] forMode:NSRunLoopCommonModes];

self.link = nil;

}

}-(void)updataFrame {CGRect frame = self.scanLayer.frame;if (self.scanLayer.frame.origin.y > self.boxView.frame.size.height) {frame.origin.y = -20;self.scanLayer.frame = frame;}else{frame.origin.y += 3;self.scanLayer.frame = frame;}}-(void)viewDidDisappear:(BOOL)animated{[super viewDidDisappear:animated];// 记得释放CADisplayLink对象if (self.link != nil) {[self.link invalidate];self.link = nil;}
}// 返回上一个界面
-(void)goBack {[self.navigationController popViewControllerAnimated:YES];
}// 二维码扫描完成
-(void)doneClick {// 设置代理if ([self.delegate respondsToSelector:@selector(scanQrcodeWithNString:)]) {[self.delegate scanQrcodeWithNString:self.string];}[self.navigationController popToRootViewControllerAnimated:YES];
}
@end