关于条形码， UPC-E 和 EAN-8 具有相同的位数。的（8）
当我扫描条形码时，我必须删除校验位。我必须删除它以匹配数据库中的条形码。
如何区分这两个？对于我的其他条形码，我根据数字长度进行区分并删除最后一位数字，但对于这两个数字，我不能因为它们而无法使用。两个都是8位，只需要1个删除校验位
不需要删除EAN-8的校验位
UPC-E的校验位是需要删除的字符索引7（最后一位）以及索引0（第一位）的系统字符数。
有没有办法可以根据校验位算法区分，或者......
答案 0 :(得分：2)
我认为你永远都不会。 EAN-8和UPC-E具有不同的校验和机制。对于UPC-E，首先扩展到UPC-A，然后计算校验和。 Fo EAN-8，您只需使用前7位数字。如果校验位仅对EAN-8或UPC-E有效，那么您已得到答案。但如果两者都匹配（我相信可能会发生），那么你就无法根据数字确定它是EAN8还是UPCE。
答案 1 :(得分：1)
我根本不认为这个问题与Swift有关。我认为条形码扫描仪是通过USB端口连接的。扫描仪可能伪装成键盘和＆＃34;类型＆＃34;解码数据。您需要参考扫描仪的文档，了解如何重新配置扫描仪以提供除解码数据之外的诊断数据。诊断将包括条形码类型。
作为一种解决方法，您可以删除最后一位数字，尝试数据库查找，如果失败则删除第一个数字并再次尝试查找。
答案 2 :(得分：1)
结束了解决方案..如果没有连接，请删除并重试。谢谢库巴
if (barcodeLength == 13) {
// EAN-13 \\
// ********** Database Function ********** Database Function ********** \\
// 1
let urlString: String = "http://\(hostString):\(portString)/barcode.php?&password=\(passString)&db=\(dbString)&barNum=\(self.scannedBarcode)"
let url: NSURL? = NSURL(string: urlString)!
let urlSession = NSURLSession.sharedSession()
//2
let jsonQuery = urlSession.dataTaskWithURL(url!, completionHandler: { data, response, error -> Void in
if (error != nil) {
println("\(error.localizedDescription)")
}
var err: NSError?
var jsonResult: Array? = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: &err) as NSArray?
if (err != nil) {
println("Can't connect using credentials")
println("JSON Error \(err!.localizedDescription)")
}
if jsonResult?.count == 0 {
println("Check digit removed from EAN-13")
self.scannedBarcode.removeAtIndex(self.scannedBarcode.endIndex.predecessor())
println(self.scannedBarcode)
self.jsonComp()
return
}
println("Well, this is 13 digit EAN-13")
// 4
let itemID: String! = jsonResult![0]["ITEM_ID"] as NSString
let itemName: String! = jsonResult![0]["ITEM_Kitchen_Name"] as NSString
let itemPrice: String! = jsonResult![0]["ITEM_Sale_Price"] as NSString
println(itemID, itemName, itemPrice)
self.selectedID = itemID
self.selectedName = itemName
self.selectedPrice = itemPrice
dispatch_async(dispatch_get_main_queue(), {
self.performSegueWithIdentifier("editPrice", sender: AnyObject?())
//
})
})
// 5
jsonQuery.resume()
}
else if (barcodeLength == 12) {
// UPC-A \\
// ********** Database Function ********** Database Function ********** \\
// 1
let urlString: String = "http://\(hostString):\(portString)/barcode.php?&password=\(passString)&db=\(dbString)&barNum=\(self.scannedBarcode)"
let url: NSURL? = NSURL(string: urlString)!
let urlSession = NSURLSession.sharedSession()
//2
let jsonQuery = urlSession.dataTaskWithURL(url!, completionHandler: { data, response, error -> Void in
if (error != nil) {
println("\(error.localizedDescription)")
}
var err: NSError?
var jsonResult: Array? = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: &err) as NSArray?
if (err != nil) {
println("Can't connect using credentials")
println("JSON Error \(err!.localizedDescription)")
}
if jsonResult?.count == 0 {
println("Check digit removed from UPC-A")
self.scannedBarcode.removeAtIndex(self.scannedBarcode.endIndex.predecessor())
println(self.scannedBarcode)
self.jsonComp()
return
}
println("Well, this is 12 digit UPC-A")
// 4
let itemID: String! = jsonResult![0]["ITEM_ID"] as NSString
let itemName: String! = jsonResult![0]["ITEM_Kitchen_Name"] as NSString
let itemPrice: String! = jsonResult![0]["ITEM_Sale_Price"] as NSString
println(itemID, itemName, itemPrice)
self.selectedID = itemID
self.selectedName = itemName
self.selectedPrice = itemPrice
dispatch_async(dispatch_get_main_queue(), {
self.performSegueWithIdentifier("editPrice", sender: AnyObject?())
//
})
})
// 5
jsonQuery.resume()
}
else if (barcodeLength == 8) {
// ********** Database Function ********** Database Function ********** \\
// 1
let urlString: String = "http://\(hostString):\(portString)/barcode.php?&password=\(passString)&db=\(dbString)&barNum=\(self.scannedBarcode)"
let url: NSURL? = NSURL(string: urlString)!
let urlSession = NSURLSession.sharedSession()
//2
let jsonQuery = urlSession.dataTaskWithURL(url!, completionHandler: { data, response, error -> Void in
if (error != nil) {
println("\(error.localizedDescription)")
}
var err: NSError?
var jsonResult: Array? = NSJSONSerialization.JSONObjectWithData(data, options: NSJSONReadingOptions.MutableContainers, error: &err) as NSArray?
if (err != nil) {
println("Can't connect using credentials")
println("JSON Error \(err!.localizedDescription)")
}
if jsonResult?.count == 0 {
println("Well, this is UPC-E")
self.scannedBarcode.removeAtIndex(self.scannedBarcode.startIndex)
self.scannedBarcode.removeAtIndex(self.scannedBarcode.endIndex.predecessor())
println(self.scannedBarcode)
self.jsonComp()
return
}
println("Well, this is EAN-8")
// 4
let itemID: String! = jsonResult![0]["ITEM_ID"] as NSString
let itemName: String! = jsonResult![0]["ITEM_Kitchen_Name"] as NSString
if jsonResult![0]["ITEM_Sale_Price"] == nil {
println("No Sale Price")
dispatch_async(dispatch_get_main_queue(), {
HUDController.sharedController.hide(afterDelay: 0.1)
})
var refreshAlert = UIAlertController(title: "Camaleon Reports", message: "Barcode does not have a price set", preferredStyle: UIAlertControllerStyle.Alert)
refreshAlert.addAction(UIAlertAction(title: "Retry", style: .Default, handler: { (action: UIAlertAction!) in
println("Yes Logic")
}))
self.presentViewController(refreshAlert, animated: true, completion: nil)
return
}
let itemPrice: String! = jsonResult![0]["ITEM_Sale_Price"] as NSString
println(itemID, itemName, itemPrice)
self.selectedID = itemID
self.selectedName = itemName
self.selectedPrice = itemPrice
dispatch_async(dispatch_get_main_queue(), {
self.performSegueWithIdentifier("editPrice", sender: AnyObject?())
//
})
})
// 5
jsonQuery.resume()
} else {
dispatch_async(dispatch_get_main_queue(), {
HUDController.sharedController.hide(afterDelay: 0.1)
})
var refreshAlert = UIAlertController(title: "Camaleon Reports", message: "Barcode does not exist", preferredStyle: UIAlertControllerStyle.Alert)
refreshAlert.addAction(UIAlertAction(title: "Retry", style: .Default, handler: { (action: UIAlertAction!) in
println("Yes Logic")
}))
self.presentViewController(refreshAlert, animated: true, completion: nil)
return
}
}