Delegate to handle scanned barcode is called more than once!? about barcodescanner

[jeryRazakarison]

Just one thing to know: when you call controller.reset(), it tells the scanner that it can capture new barcodes.
So, if you call controller.reset() in the didCaptureCode delegate (like in the example), you tell the scanner that it can scan again as soon as a barcode is scanned.

[vadymmarkov]

@githotto Hey, did you change isOneTimeSearch property to false? Because setting it to true should prevent delegate from being called multiple times.

[githotto]

@vaymmarkov Hey, I tried indeed setting isOneTimeSearch to true, but with no noticeable improvement. However when I set the scannerController.codeDelegate, .errorDelegate and .dismissalDelegate to nil in my controller.reset() func, my problems seem to have gone. Should the isOneTimeSearch have the same effect or was it just me (after a long day of bug-fixing), because today your suggestions also seems to work!?

[MincDev]

@jeryRazakarison Thank you. That solved my problem!

[junweimah]

@MincDev how did you solve this?

I have controller.isOneTimeSearch = true in my viewDidLoad(), but it still scans for multiple times after the barcodecontroller has been dismissed.

[MincDev]

@junweimah Remove the controller.reset() from the didCaptureCode delegate function. In the delegate function do what you need to do with the captured code and call controller.dismiss(animated: true, completion: nil) to dismiss the controller.

[junweimah]

@MincDev
I did that, it goes back to the previous screen, however the cpu is on 100% all the time after that, and device becomes really hot. any idea?

[MincDev]

@junweimah I am not sure as mine immediately stops the scanning process and my CPU never reaches 100%. I had the same issue with the scanner scanning multiple times and removing the controller.reset() solved it for me. What I am doing is scanning the code, then in the didCaptureCode delegate function I am querying the code against a barcode API that returns details. I completely removed the controller.reset() function from the delegate.

[junweimah]

@MincDev
This is my current didCaptureCode function

func barcodeScanner(_ controller: BarcodeScannerController, didCaptureCode code: String, type: String) {
        print("Barcode Data: \(code)")
        print("Symbology Type: \(type)")
        controller.isOneTimeSearch = true
        
        Timer.scheduledTimer(withTimeInterval: 1.0, repeats: false) { _ in
//            controller.reset(animated: true)
            controller.dismiss(animated: true, completion: nil)
        }
}

After a successful scanning, the screen will go back my previous screen, because of controller.dismiss, but my cpu goes up to 100%.

I click my scan button to bring user back to the scanning screen, but the 'Looking for your product' loading screen is still there, which is why I am guessing cpu is at 100% all the time.

How do I close the loading other than .reset?

[MincDev]

@junweimah remove the ‘controller.reset(animated: true) from the function. It is not needed here. If you call it the you are telling the scanner it is ready again to scan. Now you close it while you told it to get ready for scanning and that is why your cpu is at 100%. Just remove the reset and you will see everything wil work

[junweimah]

@MincDev
Actually i commented off that part. I try scanning for the first time, and then try to scan again to test whether it is running in the background, and I found that it won't scan for the second time, which is working.

But for some reason when I come back to the scanning screen, the loading screen(with the spinning square) is still there

[MincDev]

@junweimah I also do not have the ‘isOneTimeSearch = false’ in my delegate. I have nothing other than dismiss and just calling a function to for the API. Try taking the dismiss out of the scheduled timer. If that still doesnt work, then the problem is somewhere else. Maybe in the way you call the scanner to open?

[junweimah]

@MincDev
Possibly, ill have a further look, thanks

[vadymmarkov]

As I commented before, setting isOneTimeSearch property to true prevents delegate from being called multiple times. Please also note that you should set this property before you present BarcodeScannerViewController.