Question

What I want to do is to be able to scan a QR code and then automatically load up the relevant webpage.
I’ve downloaded the Redlaser SDK and examined it as much as I can in the time I’ve had and one thing I don’t understand is where the actual methods of the SDK are. Before I move onto ZBar I’d really like to know how this simple task can be achieved.

This is the SDK.h file:

 /*******************************************************************************
    RedLaserSDK.h

    (c) 2009-2011 eBay Inc.

    This is the public API for the RedLaser SDK.
*/
#ifdef __cplusplus
extern "C" {
#endif

// Barcode Symbologies
#define kBarcodeTypeEAN13           0x1
#define kBarcodeTypeUPCE            0x2
#define kBarcodeTypeEAN8            0x4
#define kBarcodeTypeSTICKY          0x8
#define kBarcodeTypeQRCODE          0x10
#define kBarcodeTypeCODE128         0x20
#define kBarcodeTypeCODE39          0x40
#define kBarcodeTypeDATAMATRIX      0x80
#define kBarcodeTypeITF             0x100
#define kBarcodeTypeEAN5            0x200
#define kBarcodeTypeEAN2            0x400
#define kBarcodeTypeCodabar         0x800

typedef enum
{
    RLState_EvalModeReady = 1,
    RLState_LicensedModeReady = 2,

    RLState_MissingOSLibraries = -1,
    RLState_NoCamera = -2,
    RLState_BadLicense = -3,
    RLState_ScanLimitReached = -4,
} RedLaserStatus;

#if TARGET_OS_MAC

/*******************************************************************************
    RL_GetRedLaserSDKVersion()

    This function returns the version of the RedLaser SDK, as a NSString.
    The primary purpose of this function is checking which SDK version you're 
    linking against, to compare that version against the most recent version 
    on redlaser.com. 
*/
NSString *RL_GetRedLaserSDKVersion();

/*******************************************************************************
    RL_CheckReadyStatus()

    This function returns information about whether the SDK can be used. It 
    doesn't give dynamic state information about what the SDK is currently doing.

    Generally, positive values mean you can scan, negative values mean you 
    can't. The returned value *can* change from one call to the next. 

    If this function returns a negative value, it's usually best to design your
    app so that it won't attempt to scan at all. If this function returns
    MissingOSLibraries this is especially important, as the SDK will probably 
    crash if used. See the documentation. 
*/
RedLaserStatus RL_CheckReadyStatus();


#import <Foundation/Foundation.h>

@class BarcodePickerController;

/*******************************************************************************
    BarcodeResult

    The return type of the recognizer is a NSSet of Barcode objects.    
*/
@interface BarcodeResult : NSObject <NSCoding> { }

@property (readonly) int                    barcodeType;
@property (readonly, retain) NSString       *barcodeString;
@property (readonly, copy) NSString         *extendedBarcodeString;
@property (readonly) BarcodeResult          *associatedBarcode;

@property (readonly, retain) NSDate         *firstScanTime;
@property (readonly, retain) NSDate         *mostRecentScanTime;
@property (readonly, retain) NSMutableArray *barcodeLocation;
@end

/*******************************************************************************
    BarcodePickerControllerDelegate

    The delegate receives messages about the results of a scan. This method
    gets called when a scan session completes.  
*/
@protocol BarcodePickerControllerDelegate <NSObject>
@optional
- (void) barcodePickerController:(BarcodePickerController*)picker 
        returnResults:(NSSet *)results;
@end

#if TARGET_OS_IPHONE

/*******************************************************************************
    FindBarcodesInUIImage

    Searches the given image for barcodes, and returns information on all barcodes
    that it finds. This performs an exhaustive search, which can take several 
    seconds to perform. This method searches for all barcode types. The intent
    of this method is to allow for barcode searching in photos from the photo library.
*/
NSSet *FindBarcodesInUIImage(UIImage *inputImage);


/*******************************************************************************
    CameraOverlayViewController

    An optional overlay view that is placed on top of the camera view.
    This view controller receives status updates about the scanning state, and
    can update the user interface.  
*/
@interface CameraOverlayViewController : UIViewController { }

@property (readonly, assign) BarcodePickerController *parentPicker;

- (void)barcodePickerController:(BarcodePickerController*)picker 
        statusUpdated:(NSDictionary*)status;
@end


/*******************************************************************************
    BarcodePickerController

    This ViewController subclass runs the RedLaser scanner, detects barcodes, and
    notifies its delegate of what it found.
*/
@interface BarcodePickerController : UIViewController { }

- (void) pauseScanning;
- (void) resumeScanning;
- (void) prepareToScan;
- (void) clearResultsSet;
- (void) doneScanning;
- (BOOL) hasFlash;
- (void) turnFlash:(BOOL)value;
- (void) requestCameraSnapshot;

@property (nonatomic, retain) CameraOverlayViewController *overlay;
@property (nonatomic, assign) id <BarcodePickerControllerDelegate> delegate;
@property (nonatomic, assign) BOOL scanUPCE;
@property (nonatomic, assign) BOOL scanEAN8;
@property (nonatomic, assign) BOOL scanEAN13;
@property (nonatomic, assign) BOOL scanSTICKY;
@property (nonatomic, assign) BOOL scanQRCODE;
@property (nonatomic, assign) BOOL scanCODE128;
@property (nonatomic, assign) BOOL scanCODE39;
@property (nonatomic, assign) BOOL scanDATAMATRIX;
@property (nonatomic, assign) BOOL scanITF;
@property (nonatomic, assign) BOOL scanEAN5;
@property (nonatomic, assign) BOOL scanEAN2;
@property (nonatomic, assign) BOOL scanCODABAR;
@property (nonatomic, assign) CGRect activeRegion;
@property (nonatomic, assign) UIImageOrientation orientation;
@property (nonatomic, assign) BOOL torchState;
@property (readonly, assign)  BOOL isFocusing;
@property (nonatomic, assign) BOOL useFrontCamera;

@end

#endif
#endif

#ifdef __cplusplus
}
#endif

The method in question is the doneScanning method – where is the actual body of the method found? There’s no source file for the SDK from what I can tell and this is the method I’d need to edit in my own application.

Answer 1

The actual methods of the SDK are compiled into a static library. This library is in the SDK archive at “RedLaser SDK Files/libRedLaserSDK.a”. You need to include this library in your application. We do not ship sources to the RedLaser SDK. You should not ever need to edit doneScanning or any of the other SDK methods.

The Sample application included with the SDK has a good example of basic usage. In order to scan a QR Code and open a web page, all you have to do is write a CameraOverlayViewController class that overrides the statusUpdated: method. This method should look at scanned QR Codes passed in via the status dictionary, see if the QR code does in fact contain an URL as its text (Many QR Codes are URLs, but the spec doesn’t require it; they could be any text string), and call doneScanning() to exit the scan session when a valid code has been found. Presumably you’d then open a WebView with the URL.

The file “OverlayController.m” in the Sample app has a decent example of how to set this up.