QR Reader for iPhone - iphone

Question

So i need to write a QR reader for an iphone application. Usually frameworks like ZXING and ZBAr allow you to download an application and then read the barcode. I want to integrate it within the application itself. So basically i want to be able to tap a button and have it reading the QR code. Is this possible? If so are there any proper documentation on this? I tried using ZXing but when i link binaries libZXingWidget.a is unavailable. Also the documentation is not enough to know how to integrate it within the application. So let me know.

Answer 1

Here's code to setup ZBar, make sure to add the SDK to your project and link your library.
-
(void)viewDidLoad
{
[ZBarReaderView class];
readerView.readerDelegate = self;
readerView.tracksSymbols = NO;
//CHOOSE CAMERA
if (some setting isEqual to CameraRear) {
readerView.device = [self backFacingCameraIfAvailable];
}
else {
readerView.device = [self frontFacingCameraIfAvailable];
}
[self relocateReaderPopover:[self interfaceOrientation]];
[readerView start];
}
-(AVCaptureDevice *)frontFacingCameraIfAvailable
{
NSArray *videoDevices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
AVCaptureDevice *captureDevice = nil;
for (AVCaptureDevice *device in videoDevices)
{
if (device.position == AVCaptureDevicePositionFront)
{
captureDevice = device;
break;
}
}
// couldn't find one on the front, so just get the default video device.
if ( ! captureDevice)
{
captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
}
return captureDevice;
}
-(AVCaptureDevice *)backFacingCameraIfAvailable
{
NSArray *videoDevices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
AVCaptureDevice *captureDevice = nil;
for (AVCaptureDevice *device in videoDevices)
{
if (device.position == AVCaptureDevicePositionBack)
{
captureDevice = device;
break;
}
}
// couldn't find one on the front, so just get the default video device.
if ( ! captureDevice)
{
captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
}
return captureDevice;
}
-(void)relocateReaderPopover:(UIInterfaceOrientation)toInterfaceOrientation{
if (toInterfaceOrientation == UIInterfaceOrientationLandscapeLeft) {
readerView.previewTransform = CGAffineTransformMakeRotation(M_PI_2);
} else if (toInterfaceOrientation == UIInterfaceOrientationLandscapeRight) {
readerView.previewTransform = CGAffineTransformMakeRotation(-M_PI_2);
} else if (toInterfaceOrientation== UIInterfaceOrientationPortraitUpsideDown) {
readerView.previewTransform = CGAffineTransformMakeRotation(M_PI);
} else {
readerView.previewTransform = CGAffineTransformIdentity;
}
}

Answer 2

This is a step-by-step tutorial on how to add an integrated QR code reader to your iphone app. Look at this example ZXing project if you need to know how to use it.

Answer 3

I have managed to integrate ZXING into my test project. I have done this a little time ago so I might not remember all the problems that I faced and solved.
Into my workspace folder I have copied ZXing-2.0 folder. Inside I have only left folders: cpp, docs and iphone. To my workspace (containing the test project) I have added ZXingWidget project from the folder ZXing-2.0. This allowed me to add to linking setting libZXingWidget.a.
When I build my test project, XCode detects dependency and builds the widget first and then builds the test project and links it against libZXingWidget.a.
Here's a simple view controller that I have implemented to display inside camera view able to detect QR code.
//
// MyVC.m
//
//
#import "MyVC.h"
#import "QRCodeReader.h"
#interface MyVC () {
ZXingWidgetController *_widController;
}
#end
#implementation MyVC
#synthesize labelResultString;
- (void)viewDidLoad {
[super viewDidLoad];
// Do any additional setup after loading the view from its nib.
_widController = [[ZXingWidgetController alloc] initWithDelegate:(id<ZXingDelegate>)self showCancel:YES OneDMode:NO];
QRCodeReader* qrcodeReader = [[QRCodeReader alloc] init];
NSSet *readers = [[NSSet alloc ] initWithObjects:qrcodeReader,nil];
//[qrcodeReader release];
_widController.readers = readers;
//[readers release];
//NSBundle *mainBundle = [NSBundle mainBundle];
//_widController.soundToPlay = [NSURL fileURLWithPath:[mainBundle pathForResource:#"beep-beep" ofType:#"aiff"] isDirectory:NO];
_widController.overlayView.displayedMessage = #"";
_widController.wantsFullScreenLayout = NO;
//[self presentModalViewController:_widController animated:NO];
_widController.view.frame = CGRectMake(10, 10, 300, 300);//self.view.frame;
_widController.view.autoresizingMask = UIViewAutoresizingNone;
_widController.overlayView.frame = CGRectMake(0, 0, 300, 300);
_widController.overlayView.cropRect = CGRectMake(20, 20, 260, 260);
[self.view addSubview:_widController.view];
//[_widController release];
}
- (void)viewDidUnload {
[super viewDidUnload];
self.labelResultString = nil;
}
- (void)dealloc {
self.labelResultString = nil;
}
- (void)viewWillAppear:(BOOL)animated {
[super viewWillAppear:animated];
[_widController viewWillAppear:animated];
}
- (void)viewDidAppear:(BOOL)animated {
[super viewDidAppear:animated];
[_widController viewDidAppear:animated];
[[UIApplication sharedApplication] setStatusBarHidden:NO];
}
- (void)viewWillDisappear:(BOOL)animated {
[super viewWillDisappear:animated];
[_widController viewWillDisappear:animated];
}
- (void)viewDidDisappear:(BOOL)animated {
[super viewDidDisappear:animated];
[_widController viewDidDisappear:animated];
}
#pragma mark - ZXingDelegateMethods
- (void)zxingController:(ZXingWidgetController*)controller didScanResult:(NSString *)result {
self.labelResultString.text = result;
}
- (void)zxingControllerDidCancel:(ZXingWidgetController *)controller {
[self dismissModalViewControllerAnimated:YES];
}
#end

Answer 4

Once you have ZXing set up correctly the code to get a QR reader is literally this easy:
Make sure to import these two guys for QR:
#import "ZXingWidgetController.h"
#import "QRCodeReader.h"
Then in your controller you will set up the code reader as follows:
ZXingWidgetController *widController = [[ZXingWidgetController alloc] initWithDelegate:self showCancel:YES OneDMode:NO];
QRCodeReader *qrcodeReader = [[QRCodeReader alloc] init];
NSSet *readers = [[NSSet alloc] initWithObjects:qrcodeReader,nil];
widController.readers = readers;
[self presentModalViewController:widController animated:YES];
You basically set up the controller that handles the code reading (ZXingWidgetController) and then give it a set of all the types of code readers you want (here I just used QRCodeReader.) Lastly, you just present it as a modal view controller.
Then you will need to implement the <ZXingDelegate> and the following delegate functions:
- (void)zxingController:(ZXingWidgetController*)controller didScanResult:(NSString *)result
{
[self dismissModalViewControllerAnimated:YES];
NSLog(#"%#",result); //Simple NSString result.
}
- (void)zxingControllerDidCancel:(ZXingWidgetController*)controller
{
[self dismissModalViewControllerAnimated:YES];
NSLog(#"Cancelled");
}
The hardest part is just setting it up. I found this tutorial to be the most helpful (Sorry that I am using a link): How to install ZXing in Xcode 4 The comments are also helpful if you have any problems.