如何从一个函数中获取值并在swift中的另一个函数中使用它
如何从一个函数中获取值并在swift中的另一个函数中使用它
提问于 2016-11-17 01:05:11
我有这个功能
func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [Any]!, from connection: AVCaptureConnection!) {
// Check if the metadataObjects array is not nil and it contains at least one object.
if metadataObjects == nil || metadataObjects.count == 0 {
qrCodeFrameView?.frame = CGRect.zero
messageLabel.text = "No QR/barcode is detected"
return
}
//Get metadata object
let metadataObj = metadataObjects[0] as! AVMetadataMachineReadableCodeObject
if supportedCodeTypes.contains(metadataObj.type) {
//if the found metadata is equal to the QR code metadata then update the status label's text and set the the bounds
let barCodeObject = videoPreviewLayer?.transformedMetadataObject(for: metadataObj)
qrCodeFrameView?.frame = barCodeObject!.bounds
if metadataObj.stringValue != nil {
messageLabel.text = metadataObj.stringValue
//Searches firebase for existing barcode
}
let itemToSearchFor = metadataObj.stringValue
let itemID = metadataObj.stringValue
guard let Description = productDescriptionTextField.text,
let price = priceTextField.text,
let location = productLocationTextField.text
else{
print("Fill basic product information")
return
}
let ref = FIRDatabase.database().reference(fromURL: "")
// creating an item child node
let values = ["Item Description": Description, "Image": price, "Location": location, "Price": price ]
let items = ref.child("Items").child(itemID!)
items.updateChildValues(values, withCompletionBlock: { (err, ref) in
if err != nil {
print(err)
return
} })
FIRDatabase.database().reference().child("Items").child(itemToSearchFor!).observeSingleEvent(of: .value, with:{(snap) in
print(snap)
})
}}如何从上面的函数中获取"itemID“的值，并在下面的函数中使用它。我曾尝试将函数captureOuput嵌套在函数enterNewProduct中，但它不起作用。
func enterNewProduct() {
// This is my attempt to nest the function captureOutput inside function enterNewProduct but its not working.
// func captureOutput(_ captureOutput: AVCaptureOutput!, didOutputMetadataObjects metadataObjects: [Any]!, from connection: AVCaptureConnection!){
return itemID
}
guard let Description = self.productDescriptionTextField.text,
let price = self.priceTextField.text,
let location = self.productLocationTextField.text
else{
print("Fill basic product information")
return
}
let ref = FIRDatabase.database().reference(fromURL: " /")
// creating an item child node
let values = ["Item Description": Description, "Image": price, "Location": location, "Price": price ]
let items = ref.child("Items").child(itemID)
items.updateChildValues(values, withCompletionBlock: { (err, ref) in
if err != nil {
print(err)
return
}
})我之所以考虑将captureOutput中的值嵌套或导入到enterNewProduct中，是因为我需要在enterNewProduct中使用itemID (已在captureOutput中定义)，但它在enterNewProduct中被标记为未解析的标识符。我已经被困在这件事上很久了。请告诉我任何关于如何解决这个问题的想法。
回答 1
Stack Overflow用户
发布于 2016-11-17 02:34:30
尝试在任何函数的外部声明类内的itemId变量。这将使变量对类中的任何函数都可用。
class MainViewController: UIViewController {
var itemId: String! = String()
func captureOutput() {
print(self.itemId)
//will print whatever the current string value of itemId is
}
func enterNewProduct() {
print(self.itemId)
//will print whatever the current string value of itemId is
}
func otherFunctions() {
print(self.itemId)
//will print whatever the current string value of itemId is
}
} 页面原文内容由Stack Overflow提供。腾讯云小微IT领域专用引擎提供翻译支持
原文链接：
https://stackoverflow.com/questions/40638066
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