使用AVFoundation在Swift 3.0中扫描条形码或QR码 [英] Scanning Barcode or QR code in Swift 3.0 using AVFoundation
问题描述
我正在关注 教程 ，并试图将代码从Swift 2.0转换为3.0.但是，当我启动该应用程序时，该应用程序无法运行！我的意思是，什么都没有发生！这是我的代码:
I am following this tutorial and tried to convert codes form Swift 2.0 to 3.0. But when I launched the application, the app doesn't work! I mean, nothing happens! Here is my code:
ViewController:
class ViewController: UIViewController ,BarcodeDelegate {
override func prepare(for segue: UIStoryboardSegue, sender: Any?) {
let barcodeViewController: BarcodeViewController = segue.destination as! BarcodeViewController
barcodeViewController.delegate = self
}
func barcodeReaded(barcode: String) {
codeTextView.text = barcode
print(barcode)
}
}
BarcodeVC:
import AVFoundation
protocol BarcodeDelegate {
func barcodeReaded(barcode: String)
}
class BarcodeViewController: UIViewController,AVCaptureMetadataOutputObjectsDelegate {
var delegate: BarcodeDelegate?
var captureSession: AVCaptureSession!
var code: String?
override func viewDidLoad() {
super.viewDidLoad()
// Do any additional setup after loading the view.
print("works")
self.captureSession = AVCaptureSession();
let videoCaptureDevice: AVCaptureDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
do {
let videoInput = try AVCaptureDeviceInput(device: videoCaptureDevice)
if self.captureSession.canAddInput(videoInput) {
self.captureSession.addInput(videoInput)
} else {
print("Could not add video input")
}
let metadataOutput = AVCaptureMetadataOutput()
if self.captureSession.canAddOutput(metadataOutput) {
self.captureSession.addOutput(metadataOutput)
metadataOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
metadataOutput.metadataObjectTypes = [AVMetadataObjectTypeQRCode,AVMetadataObjectTypeEAN8Code, AVMetadataObjectTypeEAN13Code, AVMetadataObjectTypePDF417Code]
} else {
print("Could not add metadata output")
}
let previewLayer = AVCaptureVideoPreviewLayer(session: self.captureSession)
previewLayer?.frame = self.view.layer.bounds
self.view.layer .addSublayer(previewLayer!)
self.captureSession.startRunning()
} catch let error as NSError {
print("Error while creating vide input device: \(error.localizedDescription)")
}
}
//I THINK THIS METHOD NOT CALL !
private func captureOutput(captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [AnyObject]!, fromConnection connection: AVCaptureConnection!) {
// This is the delegate'smethod that is called when a code is readed
for metadata in metadataObjects {
let readableObject = metadata as! AVMetadataMachineReadableCodeObject
let code = readableObject.stringValue
// If the code is not empty the code is ready and we call out delegate to pass the code.
if code!.isEmpty {
print("is empty")
}else {
self.captureSession.stopRunning()
self.dismiss(animated: true, completion: nil)
self.delegate?.barcodeReaded(barcode: code!)
}
}
}
以下是输出:
2016-09-17 18:10:26.000919 BarcodeScaning [2610:674253] [MC] systemgroup.com.apple.configurationprofiles路径的系统组容器为/private/var/containers/Shared/SystemGroup/systemgroup.com.apple.configurationprofiles 2016-09-17 18:10:26.007782 BarcodeScaning [2610:674253] [MC] 从公共有效用户设置中读取.
2016-09-17 18:10:26.000919 BarcodeScaning[2610:674253] [MC] System group container for systemgroup.com.apple.configurationprofiles path is /private/var/containers/Shared/SystemGroup/systemgroup.com.apple.configurationprofiles 2016-09-17 18:10:26.007782 BarcodeScaning[2610:674253] [MC] Reading from public effective user settings.
推荐答案
第一步需要声明对任何用户私有数据类型的访问，这是iOS 10中的新要求.您应用的Info.plist以及目的字符串.
The first step needs to be declare access to any user private data types that is a new requirement in iOS 10. You can do it by adding a usage key to your app’s Info.plist together with a purpose string.
因为您使用的是以下框架之一，并且未能声明使用情况，因此您的应用在首次进行访问时会崩溃:
Because if you are using one of the following frameworks and fail to declare the usage your app will crash when it first makes the access:
联系人，日历，提醒，照片，蓝牙共享，麦克风，相机，位置，健康，HomeKit，媒体库，Motion，CallKit，语音识别，SiriKit，电视提供商.
Contacts, Calendar, Reminders, Photos, Bluetooth Sharing, Microphone, Camera, Location, Health, HomeKit, Media Library, Motion, CallKit, Speech Recognition, SiriKit, TV Provider.
为避免崩溃，您需要将建议的密钥添加到Info.plist:
To avoid the crash you need to add the suggested key to Info.plist:
然后系统在要求用户允许访问时显示目的字符串:
And then the system shows the purpose string when asking the user to allow access:
有关它的更多信息，您可以使用本文:
For more information about it you can use this article:
我对您的BarcodeViewController进行了一些修改，以使其正常工作，如下所示:
I have done a little modifications to your BarcodeViewController to make it work properly as you can see below:
BarcodeViewController
BarcodeViewController
import UIKit
import AVFoundation
protocol BarcodeDelegate {
func barcodeReaded(barcode: String)
}
class BarcodeViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
var delegate: BarcodeDelegate?
var videoCaptureDevice: AVCaptureDevice = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
var device = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
var output = AVCaptureMetadataOutput()
var previewLayer: AVCaptureVideoPreviewLayer?
var captureSession = AVCaptureSession()
var code: String?
override func viewDidLoad() {
super.viewDidLoad()
self.view.backgroundColor = UIColor.clear
self.setupCamera()
}
private func setupCamera() {
let input = try? AVCaptureDeviceInput(device: videoCaptureDevice)
if self.captureSession.canAddInput(input) {
self.captureSession.addInput(input)
}
self.previewLayer = AVCaptureVideoPreviewLayer(session: captureSession)
if let videoPreviewLayer = self.previewLayer {
videoPreviewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill
videoPreviewLayer.frame = self.view.bounds
view.layer.addSublayer(videoPreviewLayer)
}
let metadataOutput = AVCaptureMetadataOutput()
if self.captureSession.canAddOutput(metadataOutput) {
self.captureSession.addOutput(metadataOutput)
metadataOutput.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
metadataOutput.metadataObjectTypes = [AVMetadataObjectTypeQRCode, AVMetadataObjectTypeEAN13Code]
} else {
print("Could not add metadata output")
}
}
override func viewWillAppear(_ animated: Bool) {
super.viewWillAppear(animated)
if (captureSession.isRunning == false) {
captureSession.startRunning();
}
}
override func viewWillDisappear(_ animated: Bool) {
super.viewWillDisappear(animated)
if (captureSession.isRunning == true) {
captureSession.stopRunning();
}
}
func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [Any]!, from connection: AVCaptureConnection!) {
// This is the delegate's method that is called when a code is read
for metadata in metadataObjects {
let readableObject = metadata as! AVMetadataMachineReadableCodeObject
let code = readableObject.stringValue
self.dismiss(animated: true, completion: nil)
self.delegate?.barcodeReaded(barcode: code!)
print(code!)
}
}
}
重要的一点之一是声明全局变量，并在viewWillAppear(:)和viewWillDisappear(:)方法内启动和停止captureSession.在您之前的代码中，我认为根本没有调用它，因为它从未进入处理条形码的方法内.
One of the important points was to declare the global variables and start and stop the captureSession inside the viewWillAppear(:) and viewWillDisappear(:) methods. In your previous code I think it was not called at all as it never enter inside the method to process the barcode.
希望这对您有所帮助.
这篇关于使用AVFoundation在Swift 3.0中扫描条形码或QR码的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！
