将ZBar阅读器集成到项目中：创建自定义ViewController

Question

我已将此代码添加到我的项目中。它可以正常工作，从当前视图创建并显示ZBarReaderViewController的实例。

但是我希望能够定义当前视图控制器的自定义区域，并在该区域内显示ZBarReaderViewController，同时仍显示我的“上一个/其他”视图。下面的代码以全屏模式显示视图控制器。

在界面构建器上，我只能在现有ViewController中添加UIView，因此无法将自定义视图区域与ZBarReaderViewController相关联。

我唯一能做的就是将其关联到ZBarReaderView实例，但是，由于ZBarReaderViewController是封闭源（我只能看到我正在使用的ZBar reader project上的头文件），因此无法修改行为。

我该如何解决？

(IBAction)startScanning:(id)sender {

    NSLog(@"Scanning..");
    resultTextView.text = @"Scanning..";

    ZBarReaderViewController *codeReader = [ZBarReaderViewController new];
    codeReader.readerDelegate=self;
    codeReader.supportedOrientationsMask = ZBarOrientationMaskAll;

    ZBarImageScanner *scanner = codeReader.scanner;
    [scanner setSymbology: ZBAR_I25 config: ZBAR_CFG_ENABLE to: 0];

    [self presentViewController:codeReader animated:YES completion:nil];
}

Answer 1

所以这是扫描仪视图控制器的示例。我使用情节提要创建视图，但您也可以以编程方式或使用常规笔尖进行操作。

首先，创建您的视图（在情节提要中说），然后在其中放置一个UIView，您希望在其中显示扫描仪。

现在，让我们看一下视图控制器（请查看其中的注释）：

#import <AVFoundation/AVFoundation.h>
#import "ScannerViewController.h"

@interface ScannerViewController () <AVCaptureMetadataOutputObjectsDelegate>

// UI
@property (weak, nonatomic) IBOutlet UIView *viewPreview; // Connect it to the view you created in the storyboard, for the scanner preview

// Video
@property (nonatomic, strong) AVCaptureSession *captureSession;
@property (nonatomic, strong) AVCaptureVideoPreviewLayer *videoPreviewLayer;
@property (nonatomic, strong) AVAudioPlayer *audioPlayer;
@property (nonatomic, strong) AVCaptureSession *flashLightSession;
@property (nonatomic) BOOL isReading;

@end

@implementation ScannerViewController

- (void)viewDidLoad
{
     [super viewDidLoad];

     // Initially make the captureSession object nil.
     _captureSession = nil;

    // Set the initial value of the flag to NO.
    _isReading = NO;
}

- (void)didReceiveMemoryWarning
{
    [super didReceiveMemoryWarning];
}

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

    [self startStopReading:nil];
}

- (IBAction)startStopReading:(id)sender
{
    if (!_isReading) {
        [self startReading];
    }
    else {
        // In this case the app is currently reading a QR code and it should stop doing so.
        [self stopReading];

    }

    // Set to the flag the exact opposite value of the one that currently has.
    _isReading = !_isReading;
}

#pragma mark - Private

- (BOOL)startReading
{
    NSError *error;

    // Get an instance of the AVCaptureDevice class to initialize a device object and provide the video
    // as the media type parameter.
    AVCaptureDevice *captureDevice = [AVCaptureDevice defaultDeviceWithMediaType:AVMediaTypeVideo];

    // Get an instance of the AVCaptureDeviceInput class using the previous device object.
    AVCaptureDeviceInput *input = [AVCaptureDeviceInput deviceInputWithDevice:captureDevice error:&error];

    if (!input) {
        // If any error occurs, simply log the description of it and don't continue any more.
        NSLog(@"%@", [error localizedDescription]);
        return NO;
    }

    // Initialize the captureSession object.
    _captureSession = [[AVCaptureSession alloc] init];
    // Set the input device on the capture session.
    [_captureSession addInput:input];

    // Initialize a AVCaptureMetadataOutput object and set it as the output device to the capture session.
    AVCaptureMetadataOutput *captureMetadataOutput = [[AVCaptureMetadataOutput alloc] init];
    [_captureSession addOutput:captureMetadataOutput];

    // Create a new serial dispatch queue.
    dispatch_queue_t dispatchQueue;
    dispatchQueue = dispatch_queue_create("myQueue", NULL);
    [captureMetadataOutput setMetadataObjectsDelegate:self queue:dispatchQueue];
    [captureMetadataOutput setMetadataObjectTypes:@[AVMetadataObjectTypeQRCode]]; // Add all the types you need, currently it is just QR code

    // Initialize the video preview layer and add it as a sublayer to the viewPreview view's layer.
    _videoPreviewLayer = [[AVCaptureVideoPreviewLayer alloc] initWithSession:_captureSession];
    [_videoPreviewLayer setVideoGravity:AVLayerVideoGravityResizeAspectFill];
    [_videoPreviewLayer setFrame:_viewPreview.layer.bounds];
    [_viewPreview.layer addSublayer:_videoPreviewLayer];

    // Start video capture.
    [_captureSession startRunning];

    return YES;
}

- (void)stopReading
{
    // Stop video capture and make the capture session object nil.
    [_captureSession stopRunning];
    _captureSession = nil;

    // Remove the video preview layer from the viewPreview view's layer.
    [_videoPreviewLayer removeFromSuperlayer];
}

#pragma mark - AVCaptureMetadataOutputObjectsDelegate

- (void)captureOutput:(AVCaptureOutput *)captureOutput didOutputMetadataObjects:(NSArray *)metadataObjects fromConnection:(AVCaptureConnection *)connection
{
   // Check if the metadataObjects array is not nil and it contains at least one object.
   if (metadataObjects != nil && [metadataObjects count] > 0) {

        [self performSelectorOnMainThread:@selector(stopReading) withObject:nil waitUntilDone:NO];

        _isReading = NO;

        // If the audio player is not nil, then play the sound effect.
        if (_audioPlayer) {
            [_audioPlayer play];
        }

        // This was my result, but you can search the metadataObjects array for what you need exactly
        NSString *code = [(AVMetadataMachineReadableCodeObject *)[metadataObjects objectAtIndex:0] stringValue];

    }

}