如何通过条形码将数据录入CoreData？

Question

你好，我想在核心数据中输入代码 table 通过扫描条形码来获取此代码，在将其插入数据库之前，我如何使用匹配的数组代码进行编码，然后我想要一个申请时的条件是运行第二次查看数据库中是否存在code

条形码

func barcodefunc(){
        // Get an instance of the AVCaptureDevice class to initialize a device object and provide the video
        // as the media type parameter.
        let captureDevice = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)

        // Get an instance of the AVCaptureDeviceInput class using the previous device object.
        var error:NSError?
        let input: AnyObject! = AVCaptureDeviceInput.deviceInputWithDevice(captureDevice, error: &error)

        if (error != nil) {
            // If any error occurs, simply log the description of it and don't continue any more.
            println("\(error?.localizedDescription)")
            return
        }

        // Initialize the captureSession object.
        captureSession = AVCaptureSession()
        // Set the input device on the capture session.
        captureSession?.addInput(input as AVCaptureInput)

        // Initialize a AVCaptureMetadataOutput object and set it as the output device to the capture session.
        let captureMetadataOutput = AVCaptureMetadataOutput()
        captureSession?.addOutput(captureMetadataOutput)

        // Set delegate and use the default dispatch queue to execute the call back
        captureMetadataOutput.setMetadataObjectsDelegate(self, queue: dispatch_get_main_queue())
        captureMetadataOutput.metadataObjectTypes = supportedBarCodes

        // Initialize the video preview layer and add it as a sublayer to the viewPreview view's layer.
        videoPreviewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
        videoPreviewLayer?.videoGravity = AVLayerVideoGravityResizeAspectFill
        videoPreviewLayer?.frame = view.layer.bounds
        view.layer.addSublayer(videoPreviewLayer)



        // Move the message label to the top view
        view.bringSubviewToFront(meseg)

        // Initialize QR Code Frame to highlight the QR code
        qrCodeFrameView = UIView()
        qrCodeFrameView?.layer.borderColor = UIColor.greenColor().CGColor
        qrCodeFrameView?.layer.borderWidth = 2
        view.addSubview(qrCodeFrameView!)
        view.bringSubviewToFront(qrCodeFrameView!)
    }

    func captureOutput(captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [AnyObject]!, fromConnection connection: AVCaptureConnection!) {

        // Check if the metadataObjects array is not nil and it contains at least one object.
        if metadataObjects == nil || metadataObjects.count == 0 {
            qrCodeFrameView?.frame = CGRectZero
            meseg.text = "No QR code is detected"
            return
        }

        // Get the metadata object.
        let metadataObj = metadataObjects[0] as AVMetadataMachineReadableCodeObject

        // Here we use filter method to check if the type of metadataObj is supported
        // Instead of hardcoding the AVMetadataObjectTypeQRCode, we check if the type
        // can be found in the array of supported bar codes.
        if supportedBarCodes.filter({ [=10=] == metadataObj.type }).count > 0 {
            // If the found metadata is equal to the QR code metadata then update the status label's text and set the bounds
            let barCodeObject = videoPreviewLayer?.transformedMetadataObjectForMetadataObject(metadataObj as AVMetadataMachineReadableCodeObject) as AVMetadataMachineReadableCodeObject
            qrCodeFrameView?.frame = barCodeObject.bounds

            if metadataObj.stringValue != nil {
                meseg.text = metadataObj.stringValue
            }
        }
    }

这个核心数据代码

let entityDescripition = NSEntityDescription.entityForName("Usercode", inManagedObjectContext: managedObjectContext!)
        let task = Usercode(entity: entityDescripition!, insertIntoManagedObjectContext: managedObjectContext)
        code?.the_code = "ali"
        managedObjectContext?.save(nil)

Answer 1

这是一些示例代码。首先，您需要在 AppDelegate 中设置您的核心数据堆栈，您做到了吗？如果是这样，这里是保存到核心数据的代码。

let appDelegate = UIApplication.sharedApplication().delegate as AppDelegate
let managedContext = appDelegate.managedObjectContext!
let entity = NSEntityDescription.entityForName("Usercode",inManagedObjectContext: managedContext)
let task = Usercode(entity: entity!, insertIntoManagedObjectContext: managedContext)
task.the_code = "ali"

var error: NSError?
if !managedContext.save(&error) {
println("Could not save \(error), \(error?.userInfo)")
}

如何通过条形码将数据录入CoreData？

How to enter the data into the CoreData through barcode code?

core-data

barcode

ios

swift