出于某种原因，我在代码中收到此错误，无法弄明白。我正在尝试在我的应用程序中为一个类项目安装QR扫描仪。提前谢谢。
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
如果有人有比这个更好的教程，请随意提供一个因为某些原因很难得到的。
答案 0 :(得分：1)
我遗漏了你告诉编译器委托是＆lt; AMScanViewControllerDelegate取代。
答案 1 :(得分：0)
下面：
`@protocol AMScanViewControllerDelegate <NSObject>`
应该是：
`@protocol ScannerViewControllerDelegate <NSObject>`
因为我的代码中的其他所有内容都暗示了