Question

我正在使用zbarsdk来读取条形码。它运行正常，但我的问题是我已将覆盖视图添加到ZBarReaderViewController（我的代码中的阅读器）。所以现在我尝试添加点按以聚焦功能。但它正在崩溃。以下是我的代码。提前致谢。任何想法都会很感激。

-(IBAction)scanBarCode:(id)sender
{
    barcodeClicked = 1;

    NSLog(@"TBD: scan barcode here...");
    // ADD: present a barcode reader that scans from the camera feed
    reader = [ZBarReaderViewController new];
    reader.readerDelegate = self;
    reader.supportedOrientationsMask = ZBarOrientationMaskAll;

    ZBarImageScanner *scanner = reader.scanner;
    // TODO: (optional) additional reader configuration here

    // EXAMPLE: disable rarely used I2/5 to improve performance
    [scanner setSymbology: ZBAR_I25
                   config: ZBAR_CFG_ENABLE
                       to: 0];
    reader.showsZBarControls = NO;

    UIView *ovlView = [[UIView alloc] init];
    [ovlView setFrame:CGRectMake(0, 0, 320, 480)];
    [ovlView setBackgroundColor:[UIColor clearColor]];

    UIImageView *leftBracket = [[UIImageView alloc] init];
    [leftBracket setFrame:CGRectMake(21, 100, 278, 15)];
    [leftBracket setImage:[UIImage imageNamed:@"TopBracket.png"]];

    UIImageView *rightBracket = [[UIImageView alloc] init];
    [rightBracket setFrame:CGRectMake(21, 240, 278, 15)];
    [rightBracket setImage:[UIImage imageNamed:@"BottomBracket.png"]];

    UIToolbar *bottomBar = [[UIToolbar alloc] init];
    [bottomBar setBarStyle:UIBarStyleBlackOpaque];

    if(UI_USER_INTERFACE_IDIOM() == UIUserInterfaceIdiomPhone && [UIScreen mainScreen].bounds.size.height * [UIScreen mainScreen].scale >= 1136)
    {
        [bottomBar setFrame:CGRectMake(0, 524, 320, 44)];
    }
    else
        [bottomBar setFrame:CGRectMake(0, 436, 320, 44)];

    UIBarButtonItem *cancel = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemCancel target:self action:@selector(cancelCamera)];
    /*UIBarButtonItem *flexItem = [[UIBarButtonItem alloc] initWithBarButtonSystemItem:UIBarButtonSystemItemFlexibleSpace
                                                                              target:nil
                                                                              action:nil];*/
    //UIBarButtonItem *infoButton = [[UIBarButtonItem alloc] initWithTitle:@" Info " style:UIBarButtonItemStyleBordered target:self action:@selector(infoButton)];
    /*UIButton *info = [UIButton buttonWithType:UIButtonTypeInfoLight];
    [info addTarget:self action:@selector(infoButton) forControlEvents:UIControlEventTouchUpInside];
    UIBarButtonItem *infoButton = [[UIBarButtonItem alloc] initWithCustomView:info];

    [bottomBar setItems:[NSArray arrayWithObjects:cancel,flexItem,infoButton, nil]];*/

    [bottomBar setItems:[NSArray arrayWithObjects:cancel, nil]];

    [ovlView addSubview:leftBracket];
    [ovlView addSubview:rightBracket];
    [ovlView addSubview:bottomBar];

    reader.cameraOverlayView = ovlView;

    // present and release the controller
    [self presentModalViewController:reader
                            animated: YES];
    [reader release];
}

-(void)touchesBegan:(NSSet *)touches withEvent:(UIEvent *)event {
    UIView * previewView = [[[[[[[[[[
                                     reader.view // UILayoutContainerView
                                     subviews] objectAtIndex:0] // UINavigationTransitionView
                                   subviews] objectAtIndex:0] // UIViewControllerWrapperView
                                 subviews] objectAtIndex:0] // UIView
                               subviews] objectAtIndex:0] // PLCameraView
                             subviews] objectAtIndex:0]; // PLPreviewView
    [previewView touchesBegan:touches withEvent:event];
}

Answer 1

感谢MacN00b的回答！这指出了正确的方向去找我。我已经为zbarViewController实现了tap-focus。这是一个想法：

您可以通过为其cameraOverlayView指定自定义视图，将自定义视图添加到zbarViewController。然后将TapGestureRecagonizer添加到自定义视图以捕获点按。然后，获取触摸点并使相机对焦于触摸点。您可能希望在触摸点周围添加一个小矩形（这就是我所做的）。

这里是代码（将自定义视图分配给cameraOverlayView：

UIView *view = [[UIView alloc] init];
UITapGestureRecognizer* tapScanner = [[UITapGestureRecognizer alloc] initWithTarget:self action:@selector(focusAtPoint:)];
[view addGestureRecognizer:tapScanner];    
reader.cameraOverlayView = view;

然后在选择器 focusAtPoint ：

中

- (void)focusAtPoint:(id) sender{
    CGPoint touchPoint = [(UITapGestureRecognizer*)sender locationInView:_reader.cameraOverlayView];
    double focus_x = touchPoint.x/_reader.cameraOverlayView.frame.size.width;
    double focus_y = (touchPoint.y+66)/_reader.cameraOverlayView.frame.size.height;
    NSError *error;
    NSArray *devices = [AVCaptureDevice devices];
    for (AVCaptureDevice *device in devices){
        NSLog(@"Device name: %@", [device localizedName]);
        if ([device hasMediaType:AVMediaTypeVideo]) {
            if ([device position] == AVCaptureDevicePositionBack) {
                NSLog(@"Device position : back");
                CGPoint point = CGPointMake(focus_y, 1-focus_x);
                if ([device isFocusModeSupported:AVCaptureFocusModeContinuousAutoFocus] && [device lockForConfiguration:&error]){
                    [device setFocusPointOfInterest:point];
                    CGRect rect = CGRectMake(touchPoint.x-30, touchPoint.y-30, 60, 60);
                    UIView *focusRect = [[UIView alloc] initWithFrame:rect];
                    focusRect.layer.borderColor = [UIColor whiteColor].CGColor;
                    focusRect.layer.borderWidth = 2;
                    focusRect.tag = 99;
                    [_reader.cameraOverlayView addSubview:focusRect];
                    [NSTimer scheduledTimerWithTimeInterval: 1
                                target: self
                                selector: @selector(dismissFocusRect)
                                userInfo: nil
                                repeats: NO];
                    [device setFocusMode:AVCaptureFocusModeAutoFocus];
                    [device unlockForConfiguration];
                }
            }
        }
    }
}

我在触摸点周围添加了一个白色矩形，然后使用选择器dismissFocusRect来关闭此矩形。这是代码：

- (void) dismissFocusRect{
    for (UIView *subView in _reader.cameraOverlayView.subviews)
    {
        if (subView.tag == 99)
        {
            [subView removeFromSuperview];
        }
    }
}

我希望这可以提供帮助！

Answer 2

Apple在“焦点模式”部分中查看此文档：https://developer.apple.com/library/ios/#documentation/AudioVideo/Conceptual/AVFoundationPG/Articles/04_MediaCapture.html它讨论了如何实现tap以正确聚焦。我会尝试通过

来实现这一点

CGRect screenRect = [[UIScreen mainScreen] bounds];
    screenWidth = screenRect.size.width;
    screenHeight = screenRect.size.height;  
    double focus_x = thisFocusPoint.center.x/screenWidth;
    double focus_y = thisFocusPoint.center.y/screenHeight;

    [[self captureManager].videoDevice lockForConfiguration:&error];
    [[self captureManager].videoDevice setFocusPointOfInterest:CGPointMake(focus_x,focus_y)];

好吧，如果您正在使用该视图控制器，那么如何添加（void）应该可以在barcodeviewcontroller中实现。

- (void) focusAtPoint:(CGPoint)point

{

    AVCaptureDevice *device = [[self videoInput] device];

    if ([device isFocusPointOfInterestSupported] && [device isFocusModeSupported:AVCaptureFocusModeAutoFocus]) {

        NSError *error;

        if ([device lockForConfiguration:&error]) {

            [device setFocusPointOfInterest:point];

            [device setFocusMode:AVCaptureFocusModeAutoFocus];

            [device unlockForConfiguration];

        } else {

            id delegate = [self delegate];

            if ([delegate respondsToSelector:@selector(acquiringDeviceLockFailedWithError:)]) {

                [delegate acquiringDeviceLockFailedWithError:error];

            }

        }        

    }

}

添加tap以将功能集中到ZBarReaderViewController

2 个答案: