昨天使用原生avfoundation集成一个二维码扫描报错

 unsupported type found. Use -availableMetadataObjectTypes错误的解决

 

找了好多解决方法，说是没开权限或者是要进行判断权限是否打开都试了，依然是这个问题，其实是最开始看别人文章代码的问题

 

 

- (void)initAvfoundationScan{

    

 

    _device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

    _input = [AVCaptureDeviceInput deviceInputWithDevice:self.device error:nil];

    _output = [[AVCaptureMetadataOutput alloc]init];

 

    [_output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];

    _session = [[AVCaptureSession alloc]init];

    [_session setSessionPreset:AVCaptureSessionPresetHigh];

    //设置条码类型

    

    _output.metadataObjectTypes =@[AVMetadataObjectTypeQRCode];

 

    //连接输入和输出

    

    if ([_session canAddInput:self.input])

    {

        [_session addInput:self.input];

    }

    

    if ([_session canAddOutput:self.output])

    {

        [_session addOutput:self.output];

    }

    

 

 

    //添加扫描画面

    

    _preview =[AVCaptureVideoPreviewLayer layerWithSession:_session];

    _preview.videoGravity =AVLayerVideoGravityResizeAspectFill;

   

    

    

    

    _preview.frame =self.view.layer.bounds;

    [self.view.layer insertSublayer:_preview atIndex:0];

    //开始扫描

    

    [_session startRunning];

}

 

 

红色部分是错误的顺序，看了https://stackoverflow.com/questions/18995236/ios-7-avcapturemetadataoutput-delegate-qrcode-scanner

 

正确的顺序应该是

 

 

AVCaptureMetadataOutput *output = [[AVCaptureMetadataOutput alloc] init];
[output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
[session addOutput:output];

output.metadataObjectTypes = @[AVMetadataObjectTypeQRCode];