no known instance method for selector - Obj-C - ios

Question

For some reason I am getting this error in my code and cannot figure it out. I am trying to have a QR Scanner in my app for a class project. Thanks in advance.
ScannerViewController.h:
#import "ViewController.h"
#import <AVFoundation/AVFoundation.h>
#protocol ScannerViewControllerDelegate;
#interface ScannerViewController : ViewController <AVCaptureMetadataOutputObjectsDelegate>
#property (nonatomic, weak) id<ScannerViewControllerDelegate> delegate;
#property (assign, nonatomic) BOOL touchToFocusEnabled;
- (BOOL) isCameraAvailable;
- (void) startScanning;
- (void) stopScanning;
- (void) setTorch:(BOOL) aStatus;
#end
#protocol AMScanViewControllerDelegate <NSObject>
#optional
- (void) scanViewController:(ScannerViewController *) aCtler didTapToFocusOnPoint:(CGPoint) aPoint;
- (void) scanViewController:(ScannerViewController *) aCtler didSuccessfullyScan:(NSString *) aScannedValue;
#end
ScannerViewController.m:
#import "ScannerViewController.h"
#interface ScannerViewController ()
#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 ScannerViewController
- (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]) {
// Error here ------------------------
if([self.delegate respondsToSelector:#selector(scanViewController:didTapToFocusOnPoint:)]) {
[self.delegate scanViewController:self didTapToFocusOnPoint:aPoint];
}
// ------------------- End
[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]]) {
//Error in this line here ---------------
if([self.delegate respondsToSelector:#selector(scanViewController:didSuccessfullyScan:)]) {
NSString *scannedValue = [((AVMetadataMachineReadableCodeObject *) current) stringValue];
[self.delegate scanViewController:self didSuccessfullyScan:scannedValue];
// ----------------------------End
}
}
}
}
#end
If anyone has a better tutorial than this one please feel free to provide one because they are hard to come by for some reason.
Referenced Tutorial:
http://www.ama-dev.com/iphone-qr-code-library-ios-7/

Answer 1

I'm missing where you tell the compiler that the delegate is an < AMScanViewControllerDelegate>.

Answer 2

Here:
`#protocol AMScanViewControllerDelegate <NSObject>`
Should have been:
`#protocol ScannerViewControllerDelegate <NSObject>`
Since everything else in my code hinted to that