objective-c - 从 Objc 超类继承的 Swift 子类中未调用 viewDidLoad

Question

我对 Objc 与 Swift 中的 viewDidLoad 有疑问。我不熟悉 Swift，我第一次尝试将 Swift 代码嵌入到我们的应用程序中。

我试图嵌入的快速代码有两个以这种方式声明的继承类：

ViewController_A (swift) : ViewController_B (swift) : UIViewController

视图控制器 A 和 B 都有“覆盖”viewDidLoad方法。也就是说，它们被声明为override func viewDidLoad() {}. 如果我按原样保留上述关系，并且在 and 中设置断点和语句运行 ，我print确实看到for在 for之前执行 。这似乎完全有道理。两种各自的 方法都调用. 一切都很好。viewDidLoadViewController_AViewController_BviewDidLoadViewController_AviewDidLoadviewController_BviewDidLoadsuper.viewDidLoad

我试图通过在链中添加一个 Objective-C 类来更改上述层次结构的继承：

ViewContoller_A（斯威夫特）：（ViewController_B斯威夫特）：（ViewController_C目标-C）UIViewController：。

ViewController_C还有一个viewDidLoad方法也调用[super viewDidLoad].

如果我在所有三个视图控制器中的所有三个方法的开头设置断点和prints/运行，则仅for (Objective-C) 执行。控制器 A 和 B 中的断点永远不会出现。我不确定这是否会在主题中添加不必要的信息，但有趣的是我会收到一条警告消息：NSLogviewDidLoadviewDidLoadViewController_CprintviewDidLoad

尝试在视图不在窗口层次结构中的 ViewController_C 上呈现 ViewController_A！

这似乎是在告诉我一些关于ViewController_A试图加载视图的事情。所以为了确定，作为一个测试，我注释掉了所有与 UI 相关的代码ViewContoller_C viewDidLoad。然后我没有收到该警告消息，它不应该阻止ViewController_A viewDidLoad执行，但viewDidLoad方法ViewController_A仍然没有。

请注意，ViewController_C如果添加了任何相关信息，则由模态故事板 segue 提出。

很抱歉所有这些杂乱无章，但是有没有办法强制viewDidLoadSwift 子类视图控制器中的方法在我上面概述的类继承层次结构中执行，并将 Objective-C 视图控制器添加到混合中？

谢谢你的帮助，迈克

谢谢您的回复。我在下面添加了一些代码供您查看。如果我可以添加任何其他内容，请告诉我。也许简要概述会有所帮助。

我添加的应用程序代码集代表我们用来从样品瓶中读取条形码标签的条形码扫描控制器。该代码在 objc 中。客户现在希望在相同的操作环境中读取文本代码。因此，在短期内，我将削减条形码扫描控制器以开始工作。

对于这个项目，我引入了一个由 Apple 编写的示例应用程序，可从他们的 WWDC 会话中下载，用于读取/识别电话号码。那是用swift编写的代码。到目前为止，我对这段代码做了一些小的修改。

一旦克服了技术障碍，我将重写两者。

BarCodeScan .h 和 .m 文件的开头：

    #ifndef _BARCODESCANNERCONTROLLER_H_
    #define _BARCODESCANNERCONTROLLER_H_

    #import <UIKit/UIKit.h>
    #import "SystemHeader.h"
    #import "RunParameters.h"
    #import <RDPDFKit/RDPDFKit.h>
    #import "FormInfo.h"
    #import "PatientInfo.h"
    #import "GradientButton.h"
    #import "LogTextInfo.h"
    #import "FileIOSupport.h"
    #import "PadInfo.h"
    #import "XMLiPadAndDBSupport.h"
    #import "BarCodeScanSupport.h"
    #import "LogonInfo.h"
    #import "PadInfo.h" // ocr
    #import "TextScanPreviewView.h" // ocr
    
    
    #define YesIndex                              0
    
    //
    // With PDF coordintates, pixels are spot on so no shift
    // is needed. Keep these at 0 for now.
    //
    #define SCALE_Y_ADJUSTMENT_FACTOR             0
    #define SCALE_X_ADJUSTMENT_FACTOR             0
    
    #define XML_VERSION_STR                       "<?xml version=\"1.0\"?>"
    #define XML_HEADER_NAME                       "IFD"
    
    #define ResultCount                           "ResultCount"
    #define Result                                "Result"
    
    
    #define DoNotCheck                            @"DoNotCheck"
    #define DoNotValidate                         @"DoNotValidate"
    
    //
    // These enums are for determining the action needed when
    // an incorrect but valid bar code is scanned.
    //
    
    
    //
    // These enums are for determining the action needed when
    // an incorrect but valid bar code is scanned.
    //
    typedef enum IncorrectBarCodeStatusEnum
    {
        BCNotRecognized = 1,
        BCNotUsedButBelongsToAnotherForm,
        BCAlreadyUsedByAnotherForm,
        BCIsOK
        
    } IncorrectBarCodeStatusEnum;
    
    @interface ReturnResultBarCodeStatus : NSObject
    
    @property (strong, nonatomic) FormInfo * formWhereBarCodeFound;
    @property (assign, nonatomic) IncorrectBarCodeStatusEnum incorrectBarCodeStatus;
    
    @end
    
    @interface BarCodeScanController : UIViewController <UIAlertViewDelegate>  // Merck2
    {
        BOOL isScanModeOn;
        
        UIColor *borderColorDefault;
        UIColor *viewBackgroundColorDefault;
        
        CGPoint lineStartingPoint;
        CGPoint lineEndingPoint;
        
        int barCodeImageViewUpperYCoordinate;
        
        DecoderResult * decoder;
        
        // ocr
        NSString * textScanResult;
    }
    
    //
    // This contains this page's pixel values that are read
    // from the xml incoming DBToPad file.
    //
    @property (strong, nonatomic) Barcode * barCode;
    @property (strong, nonatomic) PatientInfo * patient;
    @property (strong, nonatomic) FormInfo * form;
    @property (strong, atomic)    PadInfo * pad;
    @property (strong, atomic)    LogonInfo * logon;
    @property (strong, nonatomic) RDPDFDocument * pdfDocument;
    @property (strong, nonatomic) RDPDFDocumentView *pdfDocumentView;
    
    @property (strong, nonatomic) IBOutlet UIImageView * barCodeImageView;
    @property (strong, nonatomic) IBOutlet TextScanPreviewView * previewView3;
    @property (strong, nonatomic) IBOutlet UIView * cutoutView;
    
    @property (weak, nonatomic) IBOutlet GradientButton *submitButton;
    - (IBAction)submitButtonAction:(GradientButton *)sender;
    
    @property (weak, nonatomic) IBOutlet GradientButton *cancelButton;
    - (IBAction)cancelButtonAction:(GradientButton *)sender;
    
    @property (weak, nonatomic) IBOutlet GradientButton *scanButton;
    - (IBAction)scanButtonAction:(GradientButton *)sender;
    
    @property (weak, nonatomic) IBOutlet UILabel *formLabel;
    
    @property (weak, nonatomic) IBOutlet UILabel *barCodeResultLabel;
    
    @property (strong, nonatomic) BarCodeScanSupport *barCodeScanner;
    
    @property (strong, nonatomic) NSMutableArray *uniqueBarCodes;
    
    - (void) writeBarCodeResultsToXMLDataFile : (BOOL) dataFlag;
    
    - (void) determineIncorrectBarCodeCase
        : (NSString *) barCodeResult
        : (ReturnResultBarCodeStatus *) returnStatus;
    
    - (void) continueDecodeResultNotification;
    
    @end
    
    #endif

``````   Controller "C"

    #import "BarCodeScanController.h"
    
    @implementation ReturnResultBarCodeStatus
    
    @synthesize formWhereBarCodeFound;
    @synthesize incorrectBarCodeStatus;
    
    @end
    
    @implementation BarCodeScanController : UIViewController
    
    @synthesize barCode;
    @synthesize form;
    @synthesize pad;
    @synthesize logon;
    
    @synthesize submitButton;
    @synthesize cancelButton;
    @synthesize scanButton;
    
    @synthesize barCodeImageView;
    @synthesize previewView3;
    @synthesize cutoutView;
    
    @synthesize pdfDocument;
    @synthesize pdfDocumentView;
    
    @synthesize barCodeScanner;
    @synthesize uniqueBarCodes;
    
    @synthesize barCodeResultLabel;
    @synthesize formLabel;
    
    //
    // This is temporary for the demo. Should read whats in the file
    // if we scanned on a page, srolled to another, and came back to
    // the scanned page. But for now, just .
    //
    static NSString * saveBarCodeResult;
    
    - (id)initWithNibName:(NSString *)nibNameOrNil bundle:(NSBundle *)nibBundleOrNil
    {
        self = [super initWithNibName:nibNameOrNil bundle:nibBundleOrNil];
        if (self) {
            // Custom initialization
        }
        return self;
    }
    
    - (void)viewDidLoad
    {
        [NSThread sleepForTimeInterval : 2.0];
        
        [super viewDidLoad];
        
        if (deviceIsIPad)
        {
            self.formLabel.text = [NSString stringWithFormat:
                                 @"%@",form.form];
        }
        else
        {
            self.formLabel.text = [NSString stringWithFormat:
                                   @"                %@",form.form];
        }
        
        [self.cancelButton useAlertStyle];
        [self.submitButton useAlertStyle];
        [self.scanButton useAlertStyle];
        
        if (self.form.displaySubmitButton == NO)
        {
            self.submitButton.hidden = YES;
        }
        else
        {
            self.submitButton.hidden = NO;
        }
    
        //
        // This creates an .ifd file with no data in it. The data base server requires
        // a file with valid data or null data for each vas page. So if the user
        // evenutally enters valid data, it will overwrite this. Creating the file here
        // is completely dependent on the user having to scroll to the end of the form
        // to do a submit. In doing so, every vas page must be passed along the way
        // which will initiate this call. If we ever go back to starting out with a
        // submit button on every page when the form is brought up, then we will have
        // to create a null .ifd file in the forms modal controller, which will mean
        // we will have to have duplicate functionality in both that controller and
        // this one. Note, later added code made sure file does not first exist. It
        // may already be there if there was a crash during the submit. In this case
        // don't write a null file, and set vsLineDrawn to YES.
        //
        //
        FileIOSupport * sandbox = [[FileIOSupport alloc] init];
        
        if (![sandbox checkIfFileExistsAtPath : self.barCode.bcPngPathNameData])
        {
            [self writeBarCodeResultsToXMLDataFile : NO];
        }
        
        [[NSNotificationCenter defaultCenter] addObserver: self selector:@selector(decodeResultNotification:) name: BarCodeResultNotification object: nil];
    
        // ocr x
        // Comment out for text reader.
        // barCodeScanner = [[BarCodeScanSupport alloc] init : barCodeImageView : self
         //                                                  : self.barCode.bcFormat];
        
        // ocr x
        // Comment out for text reader
        // self.barCodeImageView.image = [UIImage imageWithContentsOfFile :
        //                               barCode.bcPngPathNameImage];
        
        [scanButton setTitle:Retry_Str forState:UIControlStateNormal];
        
        //
        // Setting isScanModeOn works for both cases below. If we have a prior
        // result we don't start the scanner but put up the previous result and
        // image. If there is no prior result, we call the scanButtonAction code
        // to start the scanner.
        //
        isScanModeOn = NO;
        
        if (self.barCode.bcImageBuffer != nil)
        {        
            self.barCodeResultLabel.hidden = NO;
            self.barCodeResultLabel.text = barCode.bcSelectedResult;
            self.barCodeResultLabel.backgroundColor = [UIColor yellowColor];
        }
        else
        {
            self.barCodeResultLabel.hidden = YES;
            self.barCodeResultLabel.text = Blank;
            
            //
            // Start scanner
            //
    
            [self scanButtonAction : scanButton];
        }
        
        // ocr
        // This normally gets allocatd in bar code scanner support which we are not
        // using for ocr. So allocate it here. We're only using the text part of it
        // so as to not disturb alot of code.
        //
        decoder = [DecoderResult alloc];
        
        // ocr
        // Comment out for text reader
        // barCodeImageViewUpperYCoordinate = self.barCodeImageView.frame.origin.y;
        
        DISPATCH_TO_MAIN_THREAD
        // ocr x
        // Comment out for text reader
        // [self startScanning];
        // [self performSegueWithIdentifier:TextReaderModalSegue  sender:self];
        DISPATCH_OUT_OF_MAIN_THREAD
        
    }

                     .
                     .
                     .

Project-Bridging-Header.h 的内容

// ocr
#import "ObjectiveCTestWithSwift.h"
#import "BarCodeScanController.h"
#import "TextScanPreviewView.h"

Apple 的控制器之一 - 控制器“B”。请注意，我尝试使用“public”关键字和不使用 viewDidLoad。

import UIKit
import AVFoundation
import Vision

// ocr
// class TextReaderViewController: UIViewController {
class TextReaderViewController : BarCodeScanController {
    // MARK: - UI objects
    //
    // ocr
    // Comment these out. These outlets will be provided by barcodescancontroller.
    // @IBOutlet weak var cutoutView: UIView!
    // @IBOutlet weak var previewView: PreviewView!
    @IBOutlet weak var numberView: UILabel!
    var maskLayer = CAShapeLayer()
    // Device orientation. Updated whenever the orientation changes to a
    // different supported orientation.
    var currentOrientation = UIDeviceOrientation.portrait
    
    // MARK: - Capture related objects
    private let captureSession = AVCaptureSession()
    let captureSessionQueue = DispatchQueue(label: "com.example.apple-samplecode.CaptureSessionQueue")
    
    var captureDevice: AVCaptureDevice?
    
    var videoDataOutput = AVCaptureVideoDataOutput()
    let videoDataOutputQueue = DispatchQueue(label: "com.example.apple-samplecode.VideoDataOutputQueue")
    
    // MARK: - Region of interest (ROI) and text orientation
    // Region of video data output buffer that recognition should be run on.
    // Gets recalculated once the bounds of the preview layer are known.
    var regionOfInterest = CGRect(x: 0, y: 0, width: 1, height: 1)
    // Orientation of text to search for in the region of interest.
    var textOrientation = CGImagePropertyOrientation.up
    
    // MARK: - Coordinate transforms
    var bufferAspectRatio: Double!
    // Transform from UI orientation to buffer orientation.
    var uiRotationTransform = CGAffineTransform.identity
    // Transform bottom-left coordinates to top-left.
    var bottomToTopTransform = CGAffineTransform(scaleX: 1, y: -1).translatedBy(x: 0, y: -1)
    // Transform coordinates in ROI to global coordinates (still normalized).
    var roiToGlobalTransform = CGAffineTransform.identity
    
    // Vision -> AVF coordinate transform.
    var visionToAVFTransform = CGAffineTransform.identity
    
    // MARK: - View controller methods
    
    // ocr
    public override func viewDidLoad() {
    
        // ocr
        print("viewDidLoad TextReaderViewController")
        
        // ocr x
        super.viewDidLoad()
        

        // Set up preview view.
        previewView3.session = captureSession
        
        // Set up cutout view.
        cutoutView.backgroundColor = UIColor.gray.withAlphaComponent(0.5)
        maskLayer.backgroundColor = UIColor.clear.cgColor
        maskLayer.fillRule = .evenOdd
        cutoutView.layer.mask = maskLayer
        
        // Starting the capture session is a blocking call. Perform setup using
        // a dedicated serial dispatch queue to prevent blocking the main thread.
        captureSessionQueue.async {
            self.setupCamera()
            
            // Calculate region of interest now that the camera is setup.
            DispatchQueue.main.async {
                // Figure out initial ROI.
                self.calculateRegionOfInterest()
            }
        }
        // ocr
        // super.viewDidLoad()
    }
               .
               .
               .

2nd of Apples Controller "A". Note I tried viewDidLoad
with "public" keyword and without.

    import Foundation
    import UIKit
    import AVFoundation
    import Vision
    
    // ocr
    // class VisionViewController: ViewController {
    class VisionViewController: TextReaderViewController {
        var request: VNRecognizeTextRequest!
        // Temporal string tracker
        let numberTracker = StringTracker()
        
        public override func viewDidLoad() {
            // Set up vision request before letting ViewController set up the camera
            // so that it exists when the first buffer is received.
            
            // ocr
            print("viewDidLoad VisionViewController")
            
            request = VNRecognizeTextRequest(completionHandler: recognizeTextHandler)
    
            super.viewDidLoad()
        }
 
                    .
                    .
                    .
    
        

标签： objective-cswiftinheritancesubclassingviewdidload

Answer 1

在

@interface BarCodeScanController : UIViewController

// place a definition, so swift (Xcode) can see it.

-(void)viewDidLoad;    

@end