iPhone QR Code Scanning iOS7

AMScanViewController.h

//
//  AMScanViewController.h
//  
//
//  Created by Alexander Mack on 11.10.13.
//  Copyright (c) 2013 ama-dev.com. All rights reserved.
//

#import <UIKit/UIKit.h>
#import <AVFoundation/AVFoundation.h>

@protocol AMScanViewControllerDelegate;

@interface AMScanViewController : UIViewController <AVCaptureMetadataOutputObjectsDelegate>

@property (nonatomic, weak) id<AMScanViewControllerDelegate> delegate;

@property (assign, nonatomic) BOOL touchToFocusEnabled;

- (BOOL) isCameraAvailable;
- (void) startScanning;
- (void) stopScanning;
- (void) setTorch:(BOOL) aStatus;

@end

@protocol AMScanViewControllerDelegate <NSObject>

@optional

- (void) scanViewController:(AMScanViewController *) aCtler didTapToFocusOnPoint:(CGPoint) aPoint;
- (void) scanViewController:(AMScanViewController *) aCtler didSuccessfullyScan:(NSString *) aScannedValue;

@end

AMScanViewController.m

//
//  AMScanViewController.m
//  
//
//  Created by Alexander Mack on 11.10.13.
//  Copyright (c) 2013 ama-dev.com. All rights reserved.
//

#import "AMScanViewController.h"

@interface AMScanViewController ()

@property (strong, nonatomic) AVCaptureDevice* device;
@property (strong, nonatomic) AVCaptureDeviceInput* input;
@property (strong, nonatomic) AVCaptureMetadataOutput* output;
@property (strong, nonatomic) AVCaptureSession* session;
@property (strong, nonatomic) AVCaptureVideoPreviewLayer* preview;

@end

@implementation AMScanViewController

- (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
{
    self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
    if (self) {
    }
    return self;
}

- (void)viewWillAppear:(BOOL)animated;
{
    [super viewWillAppear:animated];
    if(![self isCameraAvailable]) {
        [self setupNoCameraView];
    }
}

- (void) viewDidAppear:(BOOL)animated;
{
    [super viewDidAppear:animated];
}

- (void)viewDidLoad
{
    [super viewDidLoad];
    if([self isCameraAvailable]) {
        [self setupScanner];
    }
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
    // Dispose of any resources that can be recreated.
}

- (void)touchesBegan:(NSSet*)touches withEvent:(UIEvent*)evt
{
    if(self.touchToFocusEnabled) {
        UITouch *touch=[touches anyObject];
        CGPoint pt= [touch locationInView:self.view];
        [self focus:pt];
    }
}

#pragma mark -
#pragma mark NoCamAvailable

- (void) setupNoCameraView;
{
    UILabel *labelNoCam = [[UILabel alloc] init];
    labelNoCam.text = @"No Camera available";
    labelNoCam.textColor = [UIColor blackColor];
    [self.view addSubview:labelNoCam];
    [labelNoCam sizeToFit];
    labelNoCam.center = self.view.center;
}

- (NSUInteger)supportedInterfaceOrientations;
{
    return UIInterfaceOrientationMaskLandscape;
}

- (BOOL)shouldAutorotate;
{
    return (UIDeviceOrientationIsLandscape([[UIDevice currentDevice] orientation]));
}

- (void)didRotateFromInterfaceOrientation:(UIInterfaceOrientation)fromInterfaceOrientation;
{
    if([[UIDevice currentDevice] orientation] == UIDeviceOrientationLandscapeLeft) {
        AVCaptureConnection *con = self.preview.connection;
        con.videoOrientation = AVCaptureVideoOrientationLandscapeRight;
    } else {
        AVCaptureConnection *con = self.preview.connection;
        con.videoOrientation = AVCaptureVideoOrientationLandscapeLeft;
    }
}

#pragma mark -
#pragma mark AVFoundationSetup

- (void) setupScanner;
{
    self.device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    
    self.input = [AVCaptureDeviceInput deviceInputWithDevice:self.device error:nil];

    self.session = [[AVCaptureSession alloc] init];
    
    self.output = [[AVCaptureMetadataOutput alloc] init];
    [self.session addOutput:self.output];
    [self.session addInput:self.input];
    
    [self.output setMetadataObjectsDelegate:self queue:dispatch_get_main_queue()];
    self.output.metadataObjectTypes = @[AVMetadataObjectTypeQRCode];
    
    self.preview = [AVCaptureVideoPreviewLayer layerWithSession:self.session];
    self.preview.videoGravity = AVLayerVideoGravityResizeAspectFill;
    self.preview.frame = CGRectMake(0, 0, self.view.frame.size.width, self.view.frame.size.height);
    
    AVCaptureConnection *con = self.preview.connection;
    
    con.videoOrientation = AVCaptureVideoOrientationLandscapeLeft;
    
    [self.view.layer insertSublayer:self.preview atIndex:0];
}

#pragma mark -
#pragma mark Helper Methods

- (BOOL) isCameraAvailable;
{
    NSArray *videoDevices = [AVCaptureDevice devicesWithMediaType:AVMediaTypeVideo];
    return [videoDevices count] > 0;
}

- (void)startScanning;
{
    [self.session startRunning];

}

- (void) stopScanning;
{
    [self.session stopRunning];
}

- (void) setTorch:(BOOL) aStatus;
{
  	AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
		[device lockForConfiguration:nil];
		if ( [device hasTorch] ) {
			if ( aStatus ) {
				[device setTorchMode:AVCaptureTorchModeOn];
			} else {
				[device setTorchMode:AVCaptureTorchModeOff];
			}
		}
		[device unlockForConfiguration];
}

- (void) focus:(CGPoint) aPoint;
{
    AVCaptureDevice *device = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];
    if([device isFocusPointOfInterestSupported] &&
       [device isFocusModeSupported:AVCaptureFocusModeAutoFocus]) {
        CGRect screenRect = [[UIScreen mainScreen] bounds];
        double screenWidth = screenRect.size.width;
        double screenHeight = screenRect.size.height;
        double focus_x = aPoint.x/screenWidth;
        double focus_y = aPoint.y/screenHeight;
        if([device lockForConfiguration:nil]) {
            if([self.delegate respondsToSelector:@selector(scanViewController:didTapToFocusOnPoint:)]) {
                [self.delegate scanViewController:self didTapToFocusOnPoint:aPoint];
            }
            [device setFocusPointOfInterest:CGPointMake(focus_x,focus_y)];
            [device setFocusMode:AVCaptureFocusModeAutoFocus];
            if ([device isExposureModeSupported:AVCaptureExposureModeAutoExpose]){
                [device setExposureMode:AVCaptureExposureModeAutoExpose];
            }
            [device unlockForConfiguration];
        }
    }
}

#pragma mark -
#pragma mark AVCaptureMetadataOutputObjectsDelegate

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects
       fromConnection:(AVCaptureConnection *)connection
{
    for(AVMetadataObject *current in metadataObjects) {
        if([current isKindOfClass:[AVMetadataMachineReadableCodeObject class]]) {
            if([self.delegate respondsToSelector:@selector(scanViewController:didSuccessfullyScan:)]) {
                NSString *scannedValue = [((AVMetadataMachineReadableCodeObject *) current) stringValue];
                [self.delegate scanViewController:self didSuccessfullyScan:scannedValue];
            }
        }
    }
}

@end

And what about Barcode? Is there simple way how to implement bar codes scanning?

perhaps:
@Property (nonatomic, weak) id delegate;
should be: @Property (nonatomic, weak) id delegate;

I receive an error message as soon as I paste the code in XCode.

The error is related to EDScanViewControllerDelegate (.h, line 16): could you please tell me how to correct it? I have very little experience in iOS development.

I would also like to know how to fix the error @lordthistle has given.

The Error in line 16 is EDScanViewControllerDeligate should be AMScanViewControllerDelegate this should then work.
But even so you still need to call the start scan and stop scan as well as display the output. Good luck

Why are you writing ";" after declaration of methods? Looks like bad syntax.

Very useful. It saved me a lot of time.
Thanks!

@Jamonek & @lordthistle - I've fixed the issue, the delegate in the header was of wrong type

Is "setTourch" a typo? I was expecting it would be "setTorch".

Edit: Also, shouldn't "didTabToFocusOnPoint" be "didTapToFocusOnPoint"?

thx danomatika -> updated

Cool. Thanks again for this! Super useful on my current project.

Also, I replaced line 125 in AMScanViewController.m with the following:

if([[UIDevice currentDevice] orientation] == UIDeviceOrientationLandscapeLeft) {
    con.videoOrientation = AVCaptureVideoOrientationLandscapeLeft;
}
else {
    con.videoOrientation = AVCaptureVideoOrientationLandscapeRight;
}

This ensures the preview is in the correct orientation if the app starts in landscape right.

Have you tried to change the device orientation? If memory serves me right the video orientation might be wrong without adjusting ist properly

Hi, can you please tell my how the adjust the camera orientation? It's not properly displaying and I use UIInterfaceOrientationPortrait doesn't work.

Can it scan data matrix code type? I tried but it can not.

Hi, I am getting this error "No known instance method for selector 'respondsToSelector:'

what may be the cause and how to fix this. Thank you