7
我在我的應用程序中使用條碼掃描。檢測到條碼後，我停止捕獲會話以允許處理條形碼。但是，在處理條形碼之後，我希望掃描控制器保持不變，並掃描下一個條形碼。我假設開始捕獲會話（startRunning（））會做，但圖像保持凍結。我怎樣才能再次開始捕捉會話？iOS Swift條碼讀取
A
回答
11
停止會話使用此代碼
self.session.stopRunning()
首先它agian，使用此代碼
self.session.startRunning()
這裏是所有實現條形碼掃描儀的代碼...
import UIKit
import AVFoundation
class ViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
let session : AVCaptureSession = AVCaptureSession()
var previewLayer : AVCaptureVideoPreviewLayer!
var highlightView : UIView = UIView()
override func viewDidLoad() {
super.viewDidLoad()
// Allow the view to resize freely
self.highlightView.autoresizingMask = UIViewAutoresizing.FlexibleTopMargin |
UIViewAutoresizing.FlexibleBottomMargin |
UIViewAutoresizing.FlexibleLeftMargin |
UIViewAutoresizing.FlexibleRightMargin
// Select the color you want for the completed scan reticle
self.highlightView.layer.borderColor = UIColor.greenColor().CGColor
self.highlightView.layer.borderWidth = 3
// Add it to our controller's view as a subview.
self.view.addSubview(self.highlightView)
// For the sake of discussion this is the camera
let device = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
// Create a nilable NSError to hand off to the next method.
// Make sure to use the "var" keyword and not "let"
var error : NSError? = nil
let input : AVCaptureDeviceInput? = AVCaptureDeviceInput.deviceInputWithDevice(device, error: &error) as? AVCaptureDeviceInput
// If our input is not nil then add it to the session, otherwise we're kind of done!
if input != nil {
session.addInput(input)
}
else {
// This is fine for a demo, do something real with this in your app. :)
println(error)
}
let output = AVCaptureMetadataOutput()
output.setMetadataObjectsDelegate(self, queue: dispatch_get_main_queue())
session.addOutput(output)
output.metadataObjectTypes = output.availableMetadataObjectTypes
previewLayer = AVCaptureVideoPreviewLayer.layerWithSession(session) as! AVCaptureVideoPreviewLayer
previewLayer.frame = self.view.bounds
previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill
self.view.layer.addSublayer(previewLayer)
// Start the scanner. You'll have to end it yourself later.
session.startRunning()
}
// This is called when we find a known barcode type with the camera.
func captureOutput(captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [AnyObject]!, fromConnection connection: AVCaptureConnection!) {
var highlightViewRect = CGRectZero
var barCodeObject : AVMetadataObject!
var detectionString : String!
let barCodeTypes = [AVMetadataObjectTypeUPCECode,
AVMetadataObjectTypeCode39Code,
AVMetadataObjectTypeCode39Mod43Code,
AVMetadataObjectTypeEAN13Code,
AVMetadataObjectTypeEAN8Code,
AVMetadataObjectTypeCode93Code,
AVMetadataObjectTypeCode128Code,
AVMetadataObjectTypePDF417Code,
AVMetadataObjectTypeQRCode,
AVMetadataObjectTypeAztecCode
]
// The scanner is capable of capturing multiple 2-dimensional barcodes in one scan.
for metadata in metadataObjects {
for barcodeType in barCodeTypes {
if metadata.type == barcodeType {
barCodeObject = self.previewLayer.transformedMetadataObjectForMetadataObject(metadata as! AVMetadataMachineReadableCodeObject)
highlightViewRect = barCodeObject.bounds
detectionString = (metadata as! AVMetadataMachineReadableCodeObject).stringValue
self.session.stopRunning()
self.alert(detectionString)
break
}
}
}
println(detectionString)
self.highlightView.frame = highlightViewRect
self.view.bringSubviewToFront(self.highlightView)
}
func alert(Code: String){
let actionSheet:UIAlertController = UIAlertController(title: "Barcode", message: "\(Code)", preferredStyle: UIAlertControllerStyle.Alert)
// for alert add .Alert instead of .Action Sheet
// start copy
let firstAlertAction:UIAlertAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler:
{
(alertAction:UIAlertAction!) in
// action when pressed
self.session.startRunning()
})
actionSheet.addAction(firstAlertAction)
// end copy
self.presentViewController(actionSheet, animated: true, completion: nil)
}
}
+0
如果這個工作，不要忘了標記這個答案是正確的。 –
+0
我在做的事情幾乎是一樣的，但我有兩行代碼交換。我將結果字符串發送到我的處理程序，然後停止會話。它不會重新啓動。如果我在將結果發送給我的處理程序之前停止了會話，那麼它就工作了。 –
+0
在此處添加了Swift 3版本：http://stackoverflow.com/a/41512546/2108523 – mkhoshpour
10
編輯了swift 2.0的上述代碼：
import UIKit
import AVFoundation
class BarCodeViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
let session : AVCaptureSession = AVCaptureSession()
var previewLayer : AVCaptureVideoPreviewLayer!
@IBOutlet weak var highlightView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
// Allow the view to resize freely
// self.highlightView.autoresizingMask = UIViewAutoresizing.FlexibleTopMargin |
// UIViewAutoresizing.FlexibleBottomMargin |
// UIViewAutoresizing.FlexibleLeftMargin |
// UIViewAutoresizing.FlexibleRightMargin
//
// Select the color you want for the completed scan reticle
self.highlightView.layer.borderColor = UIColor.greenColor().CGColor
self.highlightView.layer.borderWidth = 3
// Add it to our controller's view as a subview.
self.view.addSubview(self.highlightView)
// For the sake of discussion this is the camera
let device = AVCaptureDevice.defaultDeviceWithMediaType(AVMediaTypeVideo)
// Create a nilable NSError to hand off to the next method.
// Make sure to use the "var" keyword and not "let"
var error : NSError? = nil
var input: AVCaptureDeviceInput = AVCaptureDeviceInput()
do {
input = try AVCaptureDeviceInput(device: device) as AVCaptureDeviceInput
} catch let myJSONError {
print(myJSONError)
}
// If our input is not nil then add it to the session, otherwise we're kind of done!
if input != AVCaptureDeviceInput() {
session.addInput(input)
}
else {
// This is fine for a demo, do something real with this in your app. :)
print(error)
}
let output = AVCaptureMetadataOutput()
output.setMetadataObjectsDelegate(self, queue: dispatch_get_main_queue())
session.addOutput(output)
output.metadataObjectTypes = output.availableMetadataObjectTypes
previewLayer = AVCaptureVideoPreviewLayer(session: session)
previewLayer.frame = self.view.bounds
previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill
self.view.layer.addSublayer(previewLayer)
// Start the scanner. You'll have to end it yourself later.
session.startRunning()
}
// This is called when we find a known barcode type with the camera.
func captureOutput(captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [AnyObject]!, fromConnection connection: AVCaptureConnection!) {
var highlightViewRect = CGRectZero
var barCodeObject : AVMetadataObject!
var detectionString : String!
let barCodeTypes = [AVMetadataObjectTypeUPCECode,
AVMetadataObjectTypeCode39Code,
AVMetadataObjectTypeCode39Mod43Code,
AVMetadataObjectTypeEAN13Code,
AVMetadataObjectTypeEAN8Code,
AVMetadataObjectTypeCode93Code,
AVMetadataObjectTypeCode128Code,
AVMetadataObjectTypePDF417Code,
AVMetadataObjectTypeQRCode,
AVMetadataObjectTypeAztecCode
]
// The scanner is capable of capturing multiple 2-dimensional barcodes in one scan.
for metadata in metadataObjects {
for barcodeType in barCodeTypes {
if metadata.type == barcodeType {
barCodeObject = self.previewLayer.transformedMetadataObjectForMetadataObject(metadata as! AVMetadataMachineReadableCodeObject)
highlightViewRect = barCodeObject.bounds
detectionString = (metadata as! AVMetadataMachineReadableCodeObject).stringValue
self.session.stopRunning()
self.alert(detectionString)
break
}
}
}
print(detectionString)
self.highlightView.frame = highlightViewRect
self.view.bringSubviewToFront(self.highlightView)
}
func alert(Code: String){
let actionSheet:UIAlertController = UIAlertController(title: "Barcode", message: "\(Code)", preferredStyle: UIAlertControllerStyle.Alert)
// for alert add .Alert instead of .Action Sheet
// start copy
let firstAlertAction:UIAlertAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.Default, handler:
{
(alertAction:UIAlertAction!) in
// action when pressed
self.session.startRunning()
})
actionSheet.addAction(firstAlertAction)
// end copy
self.presentViewController(actionSheet, animated: true, completion: nil)
}
}
+0
這很棒，謝謝！ –
3
斯威夫特3.0版本：
import UIKit
import AVFoundation
class BarCodeViewController: UIViewController, AVCaptureMetadataOutputObjectsDelegate {
let session : AVCaptureSession = AVCaptureSession()
var previewLayer : AVCaptureVideoPreviewLayer!
@IBOutlet weak var highlightView: UIView!
override func viewDidLoad() {
super.viewDidLoad()
// Allow the view to resize freely
// self.highlightView.autoresizingMask = UIViewAutoresizing.FlexibleTopMargin |
// UIViewAutoresizing.FlexibleBottomMargin |
// UIViewAutoresizing.FlexibleLeftMargin |
// UIViewAutoresizing.FlexibleRightMargin
//
// Select the color you want for the completed scan reticle
self.highlightView.layer.borderColor = UIColor.green.cgColor
self.highlightView.layer.borderWidth = 3
// Add it to our controller's view as a subview.
self.view.addSubview(self.highlightView)
// For the sake of discussion this is the camera
let device = AVCaptureDevice.defaultDevice(withMediaType: AVMediaTypeVideo)
// Create a nilable NSError to hand off to the next method.
// Make sure to use the "var" keyword and not "let"
var error : NSError? = nil
var input: AVCaptureDeviceInput = AVCaptureDeviceInput()
do {
input = try AVCaptureDeviceInput(device: device) as AVCaptureDeviceInput
} catch let myJSONError {
print(myJSONError)
}
// If our input is not nil then add it to the session, otherwise we're kind of done!
if input != AVCaptureDeviceInput() {
session.addInput(input)
}
else {
// This is fine for a demo, do something real with this in your app. :)
print(error!)
}
let output = AVCaptureMetadataOutput()
output.setMetadataObjectsDelegate(self, queue: DispatchQueue.main)
session.addOutput(output)
output.metadataObjectTypes = output.availableMetadataObjectTypes
previewLayer = AVCaptureVideoPreviewLayer(session: session)
previewLayer.frame = self.view.bounds
previewLayer.videoGravity = AVLayerVideoGravityResizeAspectFill
self.view.layer.addSublayer(previewLayer)
// Start the scanner. You'll have to end it yourself later.
session.startRunning()
}
// This is called when we find a known barcode type with the camera.
@nonobjc func captureOutput(captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [AnyObject]!, fromConnection connection: AVCaptureConnection!) {
var highlightViewRect = CGRect()
var barCodeObject : AVMetadataObject!
var detectionString : String!
let barCodeTypes = [AVMetadataObjectTypeUPCECode,
AVMetadataObjectTypeCode39Code,
AVMetadataObjectTypeCode39Mod43Code,
AVMetadataObjectTypeEAN13Code,
AVMetadataObjectTypeEAN8Code,
AVMetadataObjectTypeCode93Code,
AVMetadataObjectTypeCode128Code,
AVMetadataObjectTypePDF417Code,
AVMetadataObjectTypeQRCode,
AVMetadataObjectTypeAztecCode
]
// The scanner is capable of capturing multiple 2-dimensional barcodes in one scan.
for metadata in metadataObjects {
for barcodeType in barCodeTypes {
if metadata.type == barcodeType {
barCodeObject = self.previewLayer.transformedMetadataObject(for: metadata as! AVMetadataMachineReadableCodeObject)
highlightViewRect = barCodeObject.bounds
detectionString = (metadata as! AVMetadataMachineReadableCodeObject).stringValue
self.session.stopRunning()
self.alert(Code: detectionString)
break
}
}
}
print(detectionString)
self.highlightView.frame = highlightViewRect
self.view.bringSubview(toFront: self.highlightView)
}
func alert(Code: String){
let actionSheet:UIAlertController = UIAlertController(title: "Barcode", message: "\(Code)", preferredStyle: UIAlertControllerStyle.alert)
// for alert add .Alert instead of .Action Sheet
// start copy
let firstAlertAction:UIAlertAction = UIAlertAction(title: "OK", style: UIAlertActionStyle.default, handler:
{
(alertAction:UIAlertAction!) in
// action when pressed
self.session.startRunning()
})
actionSheet.addAction(firstAlertAction)
// end copy
self.present(actionSheet, animated: true, completion: nil)
}
}在SWIFT 3.0
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條碼SCANER：https://iosdevcenters.blogspot.com/2017/09/building-barcode-and-qr- code-reader-in.html –