快速条码扫描

Question

我试图添加条形码扫描到我的应用程序使用RSBarcodes。我有两个问题:无法更新显示扫描条形码的标签，以及委托将条形码发送到我的调用视图控制器无法工作。下面是处理扫描的视图控制器的代码：

import UIKit
import AVFoundation
import RSBarcodes

class ScanViewController: RSCodeReaderViewController {
@IBOutlet weak var label1Label: UILabel!
@IBOutlet weak var label2Label: UILabel!
@IBOutlet weak var scanLabel: UIButton!

var delegate: barcodesScannedDelegate?
var codes:[String] = []
override func viewDidLoad() {
    super.viewDidLoad()

    var code=""
    // Do any additional setup after loading the view.
    focusMarkLayer.strokeColor = UIColor.redColor().CGColor

    cornersLayer.strokeColor = UIColor.yellowColor().CGColor

    tapHandler = { point in
        //println(point)
    }

    barcodesHandler = { barcodes in

        for barcode in barcodes {
            if !contains(self.codes, barcode.stringValue) {
                self.codes.append(barcode.stringValue)
                code = barcode.stringValue
            }

        }
        println(code)
        self.label1Label.text = code
    }

}

override func didReceiveMemoryWarning() {
    super.didReceiveMemoryWarning()
    // Dispose of any resources that can be recreated.
}

@IBAction func finishedPressed(sender: UIButton) {
    delegate?.barcodesScanned(self.codes)
    self.dismissViewControllerAnimated(true, completion: nil)
}

@IBAction func cancelPressed(sender: UIButton) {
    self.dismissViewControllerAnimated(true, completion: nil)
}

}

为了确保正确执行委托，下面是我在Protocol.swift中的代码：

protocol selectCarrierDelegate {
   func selectCarrier(carrierID: String,carrier: String)
}

protocol barcodesScannedDelegate {
    func barcodesScanned(barcodes: [String])
}

以及控制器中应接收条形码的相关代码：

class InBoundViewController: UIViewController,selectCarrierDelegate,UIAlertViewDelegate,UITableViewDelegate,UITableViewDataSource,barcodesScannedDelegate {

func barcodesScanned(barcodes: [String]) {
    println("codes=\(barcodes)")
}

有谁知道为什么标签不会改变，而委托却不起作用？

Answer 1

您需要更新主线程中的所有UI。

试试这个：

dispatch_async(dispatch_get_main_queue(), { () -> Void in
    self.label1Label.text = code
})

Swift 4:

DispatchQueue.main.async {
    self.label1Label.text = code
}