helloworld-v9.6.40.md

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HelloWorld Sample

The iOS Helloworld sample illustrates how to create the simplest video streaming barcode reading app with Dynamsoft Barcode Reader (DBR) iOS SDK.

View the samples

• Objective-C HelloWorld
• Swift HelloWorld

How to Switch between One-off Scan & Continuous Scan

The default scan mode of the helloWorld sample is one-off scan. Here shows the sample code for you to switch the scan mode to continuous scan.

1. Add a result view to display the barcode result(s).

>- Objective-C >- Swift > >1. ```objc @property(nonatomic, strong) UITextView *resultView; - (void)viewDidLoad { ... [self addResultView]; } - (void)addResultView{ CGFloat viewHeight = 300; _resultView = [[UITextView alloc] initWithFrame:CGRectMake(0, UIScreen.mainScreen.bounds.size.height - viewHeight, self.view.frame.size.width, self.view.frame.size.height)]; _resultView.layer.borderColor = UIColor.whiteColor.CGColor; _resultView.layer.borderWidth = 1.0; _resultView.layer.cornerRadius = 12.0; _resultView.layer.backgroundColor = UIColor.clearColor.CGColor; _resultView.layoutManager.allowsNonContiguousLayout = false; _resultView.editable = false; _resultView.selectable = false; _resultView.textColor = UIColor.whiteColor; _resultView.textAlignment = NSTextAlignmentCenter; _resultView.hidden = false; [self.view addSubview:_resultView]; } ``` 2. ```swift class ViewController: UIViewController, DBRTextResultListener { var resultView:UITextView! ... // Add code to config the result view. func addResultView(){ let viewHeight:CGFloat = 300 resultView = UITextView(frame: CGRect(x: 0, y: mainHeight - SafeAreaBottomHeight - viewHeight , width: self.view.frame.width, height: viewHeight )) resultView.layer.borderColor = UIColor.white.cgColor resultView.layer.borderWidth = 1.0 resultView.layer.cornerRadius = 12.0 resultView.layer.backgroundColor = UIColor.clear.cgColor resultView.layoutManager.allowsNonContiguousLayout = false resultView.isEditable = false resultView.isSelectable = false resultView.font = UIFont.systemFont(ofSize: 16, weight: .medium) resultView.textColor = UIColor.white resultView.textAlignment = .center resultView.isHidden = true self.view.addSubview(resultView) } } ```

2. Modify textResultCallback. Replace the content of textResultCallback with the following code:

>- Objective-C >- Swift > >1. ```objc - (void)textResultCallback:(NSInteger)frameId imageData:(iImageData *)imageData results:(NSArray *)results{ if (results) { NSString *msgText = @""; for (NSInteger i = 0; i< [results count]; i++) { msgText = [msgText stringByAppendingString:[NSString stringWithFormat:@"\nFormat: %@\nText: %@\n", results[i].barcodeFormatString, results[i].barcodeText]]; } dispatch_async(dispatch_get_main_queue(), ^{ self.resultView.hidden = false; self.resultView.text = msgText; }); }else{ return; } } ``` 2. ```swift class ViewController: UIViewController, DBRTextResultListener { var resultView:UITextView! ... // Add code to config the result view. func textResultCallback(_ frameId: Int, imageData: iImageData, results: [iTextResult]?) { if (results != nil){ var viewText:String = "\("Total Result(s):") \(results?.count ?? 0)" for res in results! { viewText = viewText + "\n\("Format:") \(res.barcodeFormatString!) \n\("Text:") \(res.barcodeText ?? "None")\n" } DispatchQueue.main.async{ self.resultView.isHidden = false self.resultView.text = viewText } }else{ return } } } ```

Method textResultCallback is where you receive the barcode results when using video barcode decoding. It is triggered each time when an image is processed.

For more details about how to get started with Dynamsoft Barcode Reader, please view the [user guide]({{ site.oc }}user-guide.html).