Whenever you’re constructing apps, the entry barrier to some options, together with textual content recognition, is excessive. Even skilled coders take lots of time and code to get textual content recognition working in video. DataScannerViewController from the highly effective VisionKit is a self-contained scanner for textual content and barcodes that removes many of the difficulties from this job. If you want to get textual content data into your app, this API is perhaps for you. An inconvenience is that DataScannerViewController is a UIViewController and isn’t straight uncovered to SwiftUI. That’s OK as a result of UIKit isn't going away quickly. It’s straightforward to mix UIKit and SwiftUI. On this tutorial, you discover ways to use and customise DataScannerViewController in a UIKit based mostly app whereas mixing in SwiftUI elements. To do that tutorial, you want: Xcode 14.0.1 or greater. An iPhone or iPad working iOS 16 with an A12 Bionic processor or higher (Late 2017 ahead). Fundamental SwiftUI data. Getting Began Slurpy is an app that makes use of DataScannerViewController to seize textual content and barcodes and retailer them for future use. For example, a scholar visiting a museum might use Slurpy to seize textual content from exhibit data playing cards for later use. Obtain the undertaking utilizing the Obtain Supplies hyperlink on the high or backside of the tutorial. Open the folder Starter, and open the undertaking file Slurpy.xcodeproj. You’ll construct to your gadget for the tutorial. Join the gadget to your Mac and choose it because the run vacation spot. The title within the bar would be the title of your gadget. Choose the undertaking file within the Challenge navigator: Choose the goal Slurpy. Swap to the Signing and Capabilities tab. Set your personal Improvement Workforce. Change the Bundle ID to your particular crew worth. Construct and run. You see a premade tabbed interface with two tabs “Ingest” and “Use” to maintain you targeted on the cool content material. The next step will likely be so as to add DataScannerViewController to your interface. Utilizing DataScannerViewController On this part, you create and configure the DataScannerViewController from VisionKit and add that to the “Ingest” tab of the interface. You’ll quickly be capable of see what the digital camera acknowledges within the view. Making a Delegate Delegate protocols (or the delegation sample) are frequent all by way of the Apple SDKs. They help you change a category habits with no need to create a subclass. Within the Challenge navigator, within the group ViewControllers, open ScannerViewController.swift. You see an empty class declaration for ScannerViewController. Beneath the road import UIKit add the import assertion: import VisionKit
Subsequent, add the next code on the backside of ScannerViewController.swift: extension ScannerViewController: DataScannerViewControllerDelegate {
func dataScanner(
_ dataScanner: DataScannerViewController,
didAdd addedItems: [RecognizedItem],
allItems: [RecognizedItem]
) {
}
func dataScanner(
_ dataScanner: DataScannerViewController,
didUpdate updatedItems: [RecognizedItem],
allItems: [RecognizedItem]
) {
}
func dataScanner(
_ dataScanner: DataScannerViewController,
didRemove removedItems: [RecognizedItem],
allItems: [RecognizedItem]
) {
}
func dataScanner(
_ dataScanner: DataScannerViewController,
didTapOn merchandise: RecognizedItem
) {
}
}
On this extension, you conform ScannerViewController to the protocol DataScannerViewControllerDelegate. DataScannerViewControllerDelegate has strategies which might be referred to as when DataScannerViewController begins to acknowledge or stops recognizing objects in its discipline of view. Come again right here later after getting the scanner working. For now, this extension should exist to forestall compiler errors. Subsequent, prolong DataScannerViewController with a perform that instantiates and configures it to your wants. Extending DataScannerViewController On this part, make a DataScannerViewController and set it as much as scan textual content and barcodes. Add this extension on the backside of ScannerViewController.swift: extension DataScannerViewController {
static func makeDatascanner(delegate: DataScannerViewControllerDelegate)
-> DataScannerViewController {
let scanner = DataScannerViewController(
recognizedDataTypes: [
// restrict the types here later
.text()
],
isGuidanceEnabled: true,
isHighlightingEnabled: true
)
scanner.delegate = delegate
return scanner
}
}
In makeDatascanner you instantiate DataScannerViewController. The primary argument to init, recognizedDataTypes is an array of RecognizedDataType objects. The array is empty for now — you’ll add objects you need to acknowledge quickly. The arguments isGuidanceEnabled and isHighlightingEnabled add additional UI to the view that can assist you find objects. Lastly, you make ScannerViewController the delegate of DataScannerViewController. This property project connects the DataScannerViewControllerDelegate strategies you added earlier than. Including the Scanner to the View You’re prepared so as to add the scanner to the view. On the high of ScannerViewController.swift find the category declaration for ScannerViewController and add the next inside the category physique: var datascanner: DataScannerViewController?
Preserve a reference to the scanner you create so you can begin and cease the scanner. Subsequent, add this technique to the category physique: func installDataScanner() {
// 1.
guard datascanner == nil else {
return
}
// add guard right here
// 2.
let scanner = DataScannerViewController.makeDatascanner(delegate: self)
datascanner = scanner
addChild(scanner)
view.pinToInside(scanner.view)
// 3.
addChild(scanner)
scanner.didMove(toParent: self)
// 4.
do {
strive scanner.beginScanning()
} catch {
print("** oh no (unable to start out scan) - (error)")
}
}
On this code you: Test for an current scanner, so don’t add one twice. Create a scanner utilizing makeDatascanner then pin the view of DataScannerViewController contained in the safeAreaLayoutGuide space of ScannerViewController. pinToInside is an Auto Structure helper included with the starter undertaking. Add your DataScannerViewController to ScannerViewController as a toddler view controller, then inform the scanner it moved to a mum or dad view controller. Begin the DataScannerViewController. The final step is name installDataScanner when the view seems. Add this code contained in the physique of ScannerViewController: override func viewDidAppear(_ animated: Bool) {
tremendous.viewDidAppear(animated)
installDataScanner()
}
You’re prepared to fireside up the app. Construct and run. You see the app instantly crash with a console message just like this:
[access] This app has crashed as a result of it tried to entry privacy-sensitive information with out a utilization description. The app's Information.plist should include an NSCameraUsageDescription key with a string worth explaining how the app makes use of this information.
When an app must entry the digital camera, it wants to clarify...
