How do I dismiss a UIView after scanning a barcode? - objective-c

Question

I have an iPad app that I want to add a barcode reader to... this is the code for the initialization of the barcoder code:
-(void) scanInitializationCode {
_highlightView = [[UIView alloc] init];
_highlightView.autoresizingMask = UIViewAutoresizingFlexibleTopMargin|UIViewAutoresizingFlexibleLeftMargin|UIViewAutoresizingFlexibleRightMargin|UIViewAutoresizingFlexibleBottomMargin;
_highlightView.layer.borderColor = [UIColor greenColor].CGColor;
_highlightView.layer.borderWidth = 3;
[self.view addSubview:_highlightView];
// define the label to display the results of the scan
_label = [[UILabel alloc] init];
_label.frame = CGRectMake(0, self.view.bounds.size.height - 40, self.view.bounds.size.width, 40);
_label.autoresizingMask = UIViewAutoresizingFlexibleTopMargin;
_label.backgroundColor = [UIColor colorWithWhite:0.15 alpha:0.65];
_label.textColor = [UIColor whiteColor];
_label.textAlignment = NSTextAlignmentCenter;
_label.text = #"(none)";
[self.view addSubview:_label];
// session initialization
_session = [[AVCaptureSession alloc] init];
_device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
NSError *error = nil;
// define the input device
_input = [AVCaptureDeviceInput deviceInputWithDevice:_device error:&error];
if (_input) {
[_session addInput:_input];
} else {
NSLog(#"Error: %#", error);
}
// and output device
_output = [[AVCaptureMetadataOutput alloc] init];
[_output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
[_session addOutput:_output];
_output.metadataObjectTypes = [_output availableMetadataObjectTypes];
// and preview layer
_prevLayer = [AVCaptureVideoPreviewLayer layerWithSession:_session];
_prevLayer.frame = self.view.bounds;
_prevLayer.videoGravity = AVLayerVideoGravityResizeAspectFill;
[self.view.layer addSublayer:_prevLayer];
}
This is the AVCaptureMetadataOutputObjectsDelegate code:
- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection {
CGRect highlightViewRect = CGRectZero;
AVMetadataMachineReadableCodeObject *barCodeObject;
NSString *detectionString = nil;
NSArray *barCodeTypes = #[AVMetadataObjectTypeEAN13Code];
for (AVMetadataObject *metadata in metadataObjects) {
for (NSString *type in barCodeTypes) {
if ([metadata.type isEqualToString:type])
{
barCodeObject = (AVMetadataMachineReadableCodeObject *)[_prevLayer transformedMetadataObjectForMetadataObject:(AVMetadataMachineReadableCodeObject *)metadata];
highlightViewRect = barCodeObject.bounds;
detectionString = [(AVMetadataMachineReadableCodeObject *)metadata stringValue];
break;
}
}
if (detectionString != nil) {
_label.text = detectionString;
oISBNField.text = detectionString; // move detectionString to ISBN textbox
[_session stopRunning];
[_highlightView removeFromSuperview];
break;
}
else
_label.text = #"(none)";
}
This is the code that starts the scanning process by having the user tap a UIButton:
- (IBAction)aReadBarcode:(UIButton *)sender {
[self scanInitializationCode];
[_session startRunning];
// display the activity
[self.view bringSubviewToFront:_highlightView];
[self.view bringSubviewToFront:_label];
oISBNField.text = scanResults;
}
The problem is that once the scan has found the barcode, it stays visible; what I want to do is have it return to the UIView that has the button that caused it to start scanning (in other words, I want the _highlightView to disappear). I have tried all kinds of "dismissal" methods, even putting it at the back of the z-order, but none of them work. How can I make the highlightView disappear from the screen?

Answer 1

The answer:
[_prevLayer removeFromSuperlayer]; after [_session stopRunning]